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Solitary Renal Cysts; Their Symptoms When Situated at the Upper Pole of the Right Kidney1
SOLITARY RENAL CYSTS; THEIR SYMPTOMS WHEN SITUATED AT THE UPPER POLE OF THE RIGHT KIDNEY1 WILLIAM C. QUINBY
AND
ERNEST F. BRIGHT
From the Urological Clinic of the Peter Bent Brigham Hospital, Boston, Mass.
The term "solitary cyst of the kidney" or "large serous cyst of the kidney" is used today to separate these cystic formations from the multiple small retention cysts frequent in cases of chronic nephritis, and also from the condition of polycystic disease of the kidneys which is a progressive condition affecting the entire kidney, and usually bilateral. Of these large single cysts there seem to be at least three varieties: first the simple thin-walled cyst containing a serous fluid, which though doubtless formed at the expense of the parenchyma of the kidney, bears no anatomical causal relation either to the pelvis or to a calyx. Secondly those cysts which though they compress and push aside the secretory tissue of the kidney in the same way as does the first group have a deeper origin and communicate with some portion of the renal pelvis by a minute channel. These form the "pyelogenic" group of some writers. A third group includes cysts which lie outside the kidney proper communicating with the pelvis but not representing a true dilatation of it as does the pyelectasis associated with hydronephrosis. Such form the so-called "parapelvic" variety. There is also described a fourth form, the hemorrhagic solitary cyst, the name being derived from its contents. In most instances this group of cysts is an accompaniment of a benign adenoma, a definite neoplastic growth, or occasionally the hemorrhage may be due to trauma to a cyst previously of the plain serous variety. Large serous cysts of the kidney until recent years have been thought to be very rare, but there now exist in the medical literature several very comprehensive reviews each succeeding one dealing with an increasing number of cases. The most recent report, that of Simkow, deals with 315 cases, stating at the same time that the collection does not pretend to be absolutely complete. The method of formation of these large thin-walled renal cysts has been disC11ssed in numerous reports. It would seem that those cysts of the second and third group, the pyelogenic and parapelvic, must arise 1 Presented before the annual meeting of the American Urological Association, Atlantic City, N . J., May 22-2(_ 1934.
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through an aberration of development of the pelvis during embryonic life, for each is in communication with this cavity, or at any event may be assumed to have communicated with it at some period preceding its discovery. It is harder to explain the origin of the first group, more numerous than the other three, in which the cyst is situated in the cortex of the parenchyma, leaving after its removal only a shallow cup-shaped depression remote from any of the collecting structures of the organ. Of this variety of cyst the explanation afforded by the experimental work of Hepler is perhaps the best. Having obstructed by fulguration the collecting tubules of a papilla in the rabbit's kidney, while at the same time the area drained by these tubules was made avascular by arterial ligation, he was able to see the development of a cyst of considerable size quite analogous to those found in human beings. Intratubular pressure in the presence of anemia is considered to bring this about. He points out that endarteritis plus peritubular sclerosis are common in the human kidney, and that though in the kidney of nephritis this process is a diffuse one resulting in numerous cysts of no great size, if such a lesion were single as in infarct, and properly situated in the vascular bed, a large single cyst could easily be supposed to result. That these solitary cysts are not a continuation of the cyst of chronic interstitial nephritis to a larger size than usual is definitely shown by the fact that in about 65 per cent of the cases reported the parenchyma is described as normal. The commonest site of these cysts is the lower pole of the kidney; occasionally they are at the upper pole or on its equator. Often but little deformity of the kidney itself is caused; the cyst being sessile on the renal substance which forms a circular rim, triangular on section, about the beginning of the cyst wall. In gross this wall is thin, semitranslucent or opaque, and the interior of the cavity is smooth and glistening. The pale slightly yellowish fluid simulates closely on analysis, blood serum or lymph. It is not urine. Microscopically the wall of the cyst is seen to be composed of dense fibrous tissue bearing numerous capillaries. Frequently one sees areas which presumably represent occluded arterioles. In several of the sections of our own material numerous collecting tubules appear in the cyst wall. Such tubules bear a definitely flattened epithelium. No sclerosed glomeruli can be made out. In one case smooth muscle fibers are present in the wall of the cyst. Such fibers might have origin either in a portion of the pelvis or in the spiral muscle of the papilla. Such observations suggest the renal medulla as the site of origin of the cyst rather than the cortex.
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The cyst walls are lined by flattened epithelial cells, often poorly preserved, and occasionally showing infiltration by lymphocytes and plasma cells. In such a section the adjacent renal parenchyma is distorted by a chronic inflammatory process accompanied by considerable fibrosis. The glomerular tufts also are fibroid and occasionally hyaline. Sections of tissue taken a bit further from the cyst wall, however, show normal kidney. As a rule the large serous cyst of the kidney causes no especial symptoms, at least in its earlier existence while still small. It is most often discovered during palpation of the abdomen on physical examination, or as an incidental finding on abdominal section for some other lesion. In some instances the patient notes that the abdomen is increasing slowly in size, and though there is no pain, consults a physician for its explanation. On other occasions the patient notes only a sense of weight or discomfort in the loin. Such localizing symptoms as may occasionally be present are often due to interference by pressure of the cyst on the intestinal tract, stomach, or biliary passages. Frequently also the signs and symptoms of an acute or subacute pyelitis and cystitis cause the patient to seek medical advice. That secondary infection of a kidney bearing a large cyst should be common is to be assumed because of the ease with which such a formation may interfere with normal renal drainage by causing ptosis by its weight or by locally distorting the normal arrangement of pelvis or calices. As noted above the most common site for these cysts is at or near the lower pole of the kidney. Occasionally, however, they are found at the upper pole on the right side between kidney and the under surface of the liver. Because of this location their diagnosis may be quite obscure and their symptoms unusual. Of the 7 instances of solitary renal cyst which have come to operation in this hospital 4 have happened to be situated at the upper pole of the right kidney. Since the symptoms in these cases have been strikingly different from those usually ascribed to solitary cysts in general they will be discussed in detail. Case 1. A married woman 41 years old, a school teacher, entered the Brigham Hospital on October 6, 1927, complaining of a dull aching pain just below the right costal margin, which had been present intermittently for two years. During this time she had had three attacks of chills and fever, frequency of urination and pyuria. Though rest in bed relieved these attacks, the pain in the back persisted. On physical examination the lower pole of
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each kidney was palpable and there was tenderness on pressure anteriorly just under the right costal margin. Pyelograms showed normal well-filled pelves; cholecystograms were also normal. X-ray examination of the gastrointestinal tract, of the chest, and of the spine found nothing pathological. The urine contained only a few pus cells. An orthopedic consultant did not consider the pain due to bone or joint disease. She was discharged with a diagnosis of possible nephroptosis of the right kidney and slight urinary infection. On three subsequent hospital admissions for the same symptoms as above the same physical findings were present. Pelvic lavage was carried out without avail. On the fourth entrance to hospital a fitted corset and exercises were prescribed. An acute exacerbation of pain and chills togetb.er with frequency of urination caused her fifth admission. There was now found tenderness throughout the right flank most marked at the right costal margin and costo-vertebral angle. The right kidney was explored on April 21, 1928. A solitary cyst the size of a large hen's egg was found at the upper pole of the organ, slightly adherent to the under surface of the liver. The cyst was excised leaving a cone-shaped depression about 3 cm. in diameter in the parenchyma. There was no communication between the cyst and any portion of the renal pelvis. The edges of the wound in the kidney were approximated as closely as possible by interrupted sutures of fine catgut, the kidney replaced, and the wound closed. After operation, with the cessation of the cystitis in about 2 months, the patient was well and has remained so during the ensuing 4½ years. Case 2. A man 33 years old was referred to the hospital on the 30th of April, 1928, by Dr. Frederick W. Rice of Brighton. For several years he had had recurring attacks of pain in the right upper quadrant of the abdomen. There had been no urinary symptoms. These attacks had come on at intervals of about 3 months and usually had prevented work for about 2 days after which he had felt as well as ever. On the day of entrance the seizure began with severe frontal headache, malaise and slight abdominal discomfort. He was then awakened from sleep at 1 a.m. by severe non-radiating pain just below the margin of the ribs on the right, had a severe chill and subsequent fever. Examination showed fulness in the right abdomen, spasm of the right rectus muscle and a mass the size of two fists filling the upper part of the right abdomen. There was no costo-vertebral tenderness. He was immediately sent to hospital as an acute emergency and with a preoperative diagnosis of acute inflammation of the gall bladder with perforation was explored by Dr. Homans. A large retroperitoneal cystic tumor of the upper portion of the kidney was found which was punctured and drained through a second incision in the flank. After subsidence of the acute situation the cystic cavity as well as the renal pelvis was investigated by X-ray. The films demonstrated a large cyst 12 x 21 cm. above and internal to the pelvis which was seen dislocated and flattened. At a second operation on May 22, 1928, the large
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solitary cyst was excised. It had caused some torsion of the vascular pedicle and was found to communicate with the pelvis proper through an opening about 0.5 cm. in diameter. This opening was closed by a purse string suture and the parenchyma approximated by mattress sutures. Convalescence was
FIG. 1 FIG. 2 FIG. 1. Case 2. X-ray taken after injection of the cyst with sodium iodide solution. FIG. 2. Pyelogram of Case 2 showing outline of the solitary cyst and dilatation of the renal pelvis.
FIG. 3. Case 2. Photomicrograph (X75, reduced ½) of section of cyst wall sho,,-ing numerous collecting tubules.
uneventful, the infection remaining in the urinary tract on the right side responding readily to the usual measures. He has remained well during the subsequent 4 years. Microscopic report. Two sections representing a portion of the cyst wall show it to be composed of a fibrous tissue in which are found a number of
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tubules lined by a cuboidal type of cell. The cyst itself is lined by a flat cuboidal epithelium. Throughout this fibrous tissue there is a considerable infiltration of lymphocytes and plasma cells. In one section a portion of kidney substance is present which shows some of the chronic inflammatory process present in the walls. Many of the glomeruli in this portion show some hyaline change of the tufts and a slight thickening of Bowman's capsule. A few are fibrosed. They all are more or less distorted by the cyst wall.
FIG. 4. Case 2. Photomicrograph (X86, reduced½) of section of cyst wall showing chronic inflammatory process and occasional bundles of smooth muscle fibers.
FIG. 5. Case 2. Photomicrograph (X250, reduced½) of section of cyst wall showing compressed collecting tubules and chronic inflammation.
Case 3. A man of forty came to the hospital on December 12, 1932, complaining of chills, fever, dysuria, frequency of urination, and hematuria during the previous 16 days. Examination showed tenderness in the right flank and below the right costal margin anteriorly. The kidney could not be felt. The urine contained a little pus. Pyelography showed the renal pelvis deformed and pushed downward by a mass in the upper polar region of the kidney. A preoperative diagnosis of renal neoplasm was made but at operation the tumor
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was found to consist of a thin-walled cyst attached to the kidney at its upper pole. The cyst, about 5 cm. in diameter, was excised. No communication with the renal pelvis was present. Convalescence was normal and the patient was discharged 10 days later. Seen 11 months later he was well and had gained 30 pounds in weight. Pyelograms taken at this time showed that the pelvic outline, previously deformed, had resumed its normal configuration. Case 4. This 60-year-old man was seen on June 22, 1933, complaining of hematuria. He stated that about a year before, his urine had been bloody for 2 days. Following this he noted considerable shortening of the intervals of urination both day and night. A month before entrance he had had another attack of bleeding. Fhysical examination showed a man in excellent physical condition except for a slight cardiac enlargement and some increase in the
FIG.6 FIG. 7 FrG. 6. Case 3. Pyelogram before operation showing marked deformity of the upper portion of the pelvis. FIG. 7. Case 3. Pyelogram taken 10 months after operation showing normal outline of the renal pelvis.
size of the prostate. The urine was normal. Pyelography, however, discovered a cyst 7 cm. in diameter which was filled by the opaque medium casting a rounded shadow in the upper region of the pelvic outline. At operation the upper outer aspect of the kidney was found occupied by a cyst containing nearly 1500 cc. It was so closely incorporated with the parenchyma and dipped so deeply down into it that its excision was impossible; accordingly the kidney was removed. The patient was well when seen 4 months later. Gross description. Specimen consists of a kidney which weighs 150 grams. Projecting upon the middle of the convexity, a little toward the upper pole and slightly anterior of a mid-coronal section, there is a cyst 6.5 cm. in diameter. The wall is thin, opaque, membranous and pinkish-yellow. The remainder of the kidney surface appears normal. The capsule is thin and membranous. Coronal section shows an essentially negative kidney except for the deformity
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produced by the cyst. The inner wall of the cyst dips into the parenchyma as far as the level of the papillae in a sweeping hemi-spherical groove. The cyst communicates with one of the minor calices through a canal 1 mm. m
FIG.
FIG.
9. Case 4.
8. Case 4.
Pyelogram showing outline of the solitary cyst
Kidney removed at operation showing the solitary cyst in the upper
portion.
diameter and 5 mm. in length. The pelvis for the most part is pale white but there are numerous petechial hemorrhages within the mucosa in several areas. There is no infection. There is no appreciable increase in fat. The
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cortex is uniformly 7 mm. in thickness. The glomeruli can be seen but are not unusually prominent. The capsule strips with ease. The surface is smooth after stripping. There is no evidence of infection in the kidney substance. The cortical rays are well preserved. The medullary tissue is not remarkable except for the marked distortion produced by the cyst. The ureter is not remarkable. Microscopic rfport. The cyst of the kidney is lined by an imperfectly preserved, thin layer of epithelium. Immediately beneath the lining there is
FIG.10 FIG.11 FIG. 10. Case 4. Pyotomicrograph (X80, reduced ½) of section of cyst wall adjacent to kidney showing slight chronic inflammation in the cyst wall and the underlying normal renal parenchyma. FIG. 11. Case 4. Photomicrograph (X80, reduced ½) of communicating tract between cyst cavity and that of pelvis. (The partially denuded epithelium is an artefact.)
a zone of inflammation characterized by marked vascularity and chronic inflammatory cell infiltration. The renal parenchyma is not remarkable. The tubules contain hyaline and granular casts and much granular precipitate. The tubular epithelium shows only the usual post-operative degeneration. The glomeruli are not remarkable. None show arteriolar-sclerosis, capsular adhesions or capsular proliferation. There are no foci of round cells. The renal pelvis contains areas of hemorrhage and round cell infiltration. Serial sections through the small tract leading from the cyst to the calyx show at least one continuous passage, and possibly two, which is lined with transitional epithelium, and which is certainly preformed.
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An analysis of the symptoms of these cysts of the upper pole of the right kidney has been made from 32 cases found in the literature together with the 4 instances here reported. It is interesting to note a distinct tendency toward similarity. Over half these cases had pain in the right upper quadrant of the abdomen under the costal margin. This pain usually did not radiate. A few patients complained only of discomfort in this area. In a quarter of the cases the complaint was of pain in the right side of the back. In a few of these the pain radiated anteriorly, and in a few also, down the course of the ureter. In a third of the cases there were symptoms of cystitis and in a third also chills and fever were reported. Seven instances of gross hematuria are noted. In two-thirds of the group neither the kidney nor any tumor mass could be felt. When palpable it usually was so abdominally; not bimanually. Very few patients complained of tenderness on palpation. In about two-thirds of the cases, therefore, the physical examination was entirely negative. Laboratory examination showed that the urine was normal in about two-thirds of the cases reported. Pyelography in the 8 cases where it was performed gave the most accurate information, showing a deformity or displacement of the upper calices in 75 per cent of the cases. In reviewing a large number of solitary cysts of the kidney situated at other sites than the upper pole of the right kidney, we have found that in 41 cases where pyelography is recorded, 34 cases, or 83 per cent, showed abnormal pyelograms. Braasch and Carman and Herbst and Vynalek have reviewed the changes found by pyelography in cases of solitary cysts of the kidney. The most constant changes are shortening of the calices adjacent to the cyst, flattening of the portion of the true pelvis nearest to the cyst, filling defect, actual outline of the cyst, and changes in the axis of the kidney caused by the weight of a cyst situated at either pole. Accurate preoperative diagnosis of cysts of the upper pole of the right kidney has rarely been made. Only 1 of our 4 and 5 of 30 reported cases were diagnosed correctly. A diagnosis of cholecystitis was made in 9 cases. In 1 of these a ruptured gall bladder was suspected, and in 2 others jaundice due to obstruction of the common bile duct from pressure of the cyst was present. In the cases where pyelograms were made
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the diagnosis was usually tumor of the kidney; the benign cyst being found at operation. In 1 of the cases a renal stone was suspected. The above symptoms found in the cases of solitary cysts of the upper pole of the right kidney are quite in contrast to the lack of symptoms usually caused by this condition, for the cyst of the lower pole of the kidney rarely produces outstanding symptoms. As noted above, the patient with a cyst in this location usually complains of a painless palpable tumor mass or the abdominal tumor is found on physical examination. Although a solitary cyst of the upper pole of the right kidney is a rare occurrence, one must consider it in the differential diagnosis of the cause of pain in the right upper quadrant, especially in those cases where the gall bladder has been found to be normal by cholecystographic studies. Pyelography is the most accurate means of diagnosis of a solitary cyst of the kidney. REFERENCES (1) ABEL, I.: Solitary cyst of the kidney. Report of a case with review of the literature. Urol. and Cutan. Rev., 1916, xx, 617-621. (2) ALBERT: quoted by W. CALHOUN STIRLING: Large solitary hemorrhagic renal cyst with review of the literature. Report of a case. Jour. Urol., 1931, xxv, 213-222. (3) BREWER, G. E.: Simple cyst of the kidney. J our. Amer. Med. Assoc., 1908, 1, 718. (4) CUNNINGHAM, J. H.: Large solitary and multiple cysts of the kidney. Surg., Gynec. and Obstet., 1916, xxiii, 688-696. (5) DAMM, E.: Solitarcysten der Niere. Ztschr. f. urol. Chir., 1932, xxxv, 102-113. (6) DELKESKAMP, G.: Beitrage zur Nierenchirurgie. Beitr. z. klin. Chir., 1904, xliv, 1-139. (Case report on p. 58.) (7) DODSON, A. I.: Cysts of the kidney. South. Med. Jour., 1933, xxvi, 223-231. (8) D6zsA, E.: Klinische Beitrage zu den grossen serosen Cysten der Niere. Ztschr. f. urol. Chir., 1927, xxii, 70-80. (9) FULLERTON, A.: Solitary cysts of the kidney. Brit. Jour. Surg., 1927, xiv, 629-633. (10) HARPSTER, C. M., BROWN, T. H. AND DELCHER, A.: Solitary unilateral large serous cysts of the kidney with report of two cases and review of the literature. Jour. Urol., 1924, xi, 157-175. (11) HERBST, R. H. AND VYNALEK, W. J.: Solitary serous cysts with study of the X-ray observations. Jour. Amer. Med. Assoc., 1931, xcvi, 597-602. (12) HIGGINS, C. C.: Solitary cysts of the kidney. Ann. Surg., 1931, xciii, 868-879. (13) HOFER, 0.: Choledochusverschluss und Anurie
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(18) MrnET, M . H.: Kyste hematique perirenal et hydronephrose. Jour. d'urol. Med. et chir., 1921, xi, 581-585. (19) PETTINARI, V.: Contributo alla conoscenza delle cisti solitarie del rene. Arch. ital. di urol., 1929, v, 305-348. (20) PUGH, W. S.: Resection of kidney for solitary cyst. Surg. Clin. No. Amer., 1932, xii, 373-376. (21) RECAMIER: Kyste sereux du rein. Extirpation de la portion libre de la poche. Guerison. Ann. d . rnal. gen. d. org. genito-urin., 1893, xi, 185-187. (22) SECRETAN, M.: Grands kystes du rein. Jour. d'Urol., 1929, xxvii, 5-10. (23) SrMONCELLI, G.: Contributo clinico allo studio delle grandi cisti sierose del rene. Policlin. sez. chir., 1924, xxxi, 105-113. (24) SMITH, L. D.: Solitary serous renal cysts. Illinois Med. Jour., 1927, lii, 291-295. (25) SouLIGoux AND GouGET: Contribution a l'etude des grands kystes hematique simples du rein. Arch. gen. de med., Avril 4, 1905. (26) SWEETSER, H.B.: Large infected solitary cyst of the kidney. Minnesota Med., 1929, xii, 786-788. (27) THOMAS, B. A.: Enormous solitary cyst of the kidney associated with pyonephrosis. Case report. Jour. Urol., 1927, xviii, 528-530. (28) TuFFIER, M.: De l'ablation par dissection des grands kystes sereux du rein. Arch. gen. de med., 1891, ii, 5-13. (29) VrETHEN, H.: Ein Fall von Solitarcyste bei Hufeisenniere. Zentralbl. f. Chir., 1926, liii, 2655-2657. (30) VOGEL: Beitrage zur Nierenchirurgie. Zwei Falle von Nierencyste. Zentralbl. f. Chir., 1912, xxxix; 1540-1544. (31) WULFF, 0 .: Uber Solitare, von Hamaturie begleitete Blutcysten in den Nieren. Arch. f. klin. Chir., 1915, cvi, 689-698. Other References (32) BRAASCH, W. F. AND CARMAN, R. D .: The pyelographic and roentgenologic diagnosis of renal tumors. Collected papers of the. Mayo Clinic and the Mayo Foundation, 1924, xvi, 327-339. (33) BRANCH, C. F. : Some observations on solitary cysts of the kidney. Jour. Urol., 1929, xxi, 451-453. (34) BRIN, M. H.: Des kystes non hydatiques du rein. W. Rapport et Inform. Assn. Franc. d'Urol., 1911, xv, 33- 234. (35) CARSON, W. J.: Solitary cysts of the kidney. Ann. Surg., 1928, lxxxvii, 250-256. (36) COLSTON, J. A. C.: Solitary cyst and papillary cystadenoma occurring simultaneously in one kidney. Jour. Urol., 1928, xix, 285-290. (37) GRUBER, G. B.: Morphologie der Missbildungen der Menschen und der Tiere. Schwalbe- Jena, 1927, iii Teil, xii Lief. S. 193. (38) HEPLER, A. B.: Solitary cysts of the kidney. A report of seven cases and observations on the pathogenesis of these cysts. Surg., Gynec. and Obstet., 1930, 1, 668- 687. (39) KAMPMEIER, 0. F.: A hitherto unrecognized mode of origin of congenital renal cysts. Surg., Gynec. and Obstet., 1923, xxxvi, 208-216. (40) LATTER!, S.: Le cisti solitarie sierose del rene. Studio clinico, anatomopatologicco e sperimentale. Arch. ital. di. urol., 1930, vi, 113-157. (41) McKIM, G. F. AND SMITH, P . G.: Solitaryserouscystsofthekidney. Jour. Urol., 1924, xii, 635-
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(43) REINECKE: Solitare vielkammerige Cyste der Niere. Virchow's Arch. f. path. Anat., 1925, ccliv, 425-438. (44) SrMKow, A.: Les grands kystes sereux der rein. (Etude clinique et chriurgicale) These de Paris. Jouve et Cie., 1932, no. 362, 87. (45) VoNACHER, J. R. AND SPRENGLER, A.: Solitary cysts of the kidney. Report of case. Illinois Med. Jour., 1927, li, 413-415.
DISCUSSION DR. W. F. BRAASCH (Rochester, Minn.): Drs. Quinby and Bright have called our attention to a very interesting symptom complex occurring with solitary cysts of the kidney. Although this condition is usually symptomless, occasionally the cyst increases in size to such an extent that it causes distress or obstructs renal drainage. Secondary infection of the cyst is occasionally observed, with resulting fever and pain. Hematuria is sometimes observed but it is usually of no serious significance. The cyst may occasionally increase rapidly in size and cause pressure atrophy of the adjacent renal tissue. Such atrophy, however, rarely is so extensive as to seriously damage renal function. Surgical interference may be necessary with these complications, but in most cases the uncomplicated cyst needs no treatment. However, the difficulty of clinical differentiation between a simple cyst and neoplasm is the usual cause for surgical exploration, and in fact makes such exploration necessary in almost every case of renal cyst. Although there are definite clinical and urographic data which differentiate simple renal cyst from renal neoplasm, nevertheless the data are often quite similar and clinical differentiation may be impossible without surgical exploration. In attempting clinical differentiation it may be stated that simple renal cysts usually exist many years without the patient being aware of them. In fact, they are often observed by the patient and known to have remained stationary for years. Unfortunately, the same data may occur with tumor of the kidney. This is also true with regard to the rate of growth, since both simple cyst and neoplasm occasionally increase rapidly in size. It is not possible to differentiate between them by palpation alone. It will be possible to differentiate simple cyst from neoplasm by means of urography in most cases, but not in all. The following urographic data are usually observed with simple cyst: (1) abbreviation of the adjacent calices; (2) compression and :flattening of the adjacent portion of the renal pelvis; and (3) change in position and axis of the kidney as the result of tumor in one pole. The outline of a simple cyst may be visible adjacent to that of the renal pelvis and its relation to the pelvic deformity may be of value in its identification.
AND
ERNEST F. BRIGHT
From the Urological Clinic of the Peter Bent Brigham Hospital, Boston, Mass.
The term "solitary cyst of the kidney" or "large serous cyst of the kidney" is used today to separate these cystic formations from the multiple small retention cysts frequent in cases of chronic nephritis, and also from the condition of polycystic disease of the kidneys which is a progressive condition affecting the entire kidney, and usually bilateral. Of these large single cysts there seem to be at least three varieties: first the simple thin-walled cyst containing a serous fluid, which though doubtless formed at the expense of the parenchyma of the kidney, bears no anatomical causal relation either to the pelvis or to a calyx. Secondly those cysts which though they compress and push aside the secretory tissue of the kidney in the same way as does the first group have a deeper origin and communicate with some portion of the renal pelvis by a minute channel. These form the "pyelogenic" group of some writers. A third group includes cysts which lie outside the kidney proper communicating with the pelvis but not representing a true dilatation of it as does the pyelectasis associated with hydronephrosis. Such form the so-called "parapelvic" variety. There is also described a fourth form, the hemorrhagic solitary cyst, the name being derived from its contents. In most instances this group of cysts is an accompaniment of a benign adenoma, a definite neoplastic growth, or occasionally the hemorrhage may be due to trauma to a cyst previously of the plain serous variety. Large serous cysts of the kidney until recent years have been thought to be very rare, but there now exist in the medical literature several very comprehensive reviews each succeeding one dealing with an increasing number of cases. The most recent report, that of Simkow, deals with 315 cases, stating at the same time that the collection does not pretend to be absolutely complete. The method of formation of these large thin-walled renal cysts has been disC11ssed in numerous reports. It would seem that those cysts of the second and third group, the pyelogenic and parapelvic, must arise 1 Presented before the annual meeting of the American Urological Association, Atlantic City, N . J., May 22-2(_ 1934.
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through an aberration of development of the pelvis during embryonic life, for each is in communication with this cavity, or at any event may be assumed to have communicated with it at some period preceding its discovery. It is harder to explain the origin of the first group, more numerous than the other three, in which the cyst is situated in the cortex of the parenchyma, leaving after its removal only a shallow cup-shaped depression remote from any of the collecting structures of the organ. Of this variety of cyst the explanation afforded by the experimental work of Hepler is perhaps the best. Having obstructed by fulguration the collecting tubules of a papilla in the rabbit's kidney, while at the same time the area drained by these tubules was made avascular by arterial ligation, he was able to see the development of a cyst of considerable size quite analogous to those found in human beings. Intratubular pressure in the presence of anemia is considered to bring this about. He points out that endarteritis plus peritubular sclerosis are common in the human kidney, and that though in the kidney of nephritis this process is a diffuse one resulting in numerous cysts of no great size, if such a lesion were single as in infarct, and properly situated in the vascular bed, a large single cyst could easily be supposed to result. That these solitary cysts are not a continuation of the cyst of chronic interstitial nephritis to a larger size than usual is definitely shown by the fact that in about 65 per cent of the cases reported the parenchyma is described as normal. The commonest site of these cysts is the lower pole of the kidney; occasionally they are at the upper pole or on its equator. Often but little deformity of the kidney itself is caused; the cyst being sessile on the renal substance which forms a circular rim, triangular on section, about the beginning of the cyst wall. In gross this wall is thin, semitranslucent or opaque, and the interior of the cavity is smooth and glistening. The pale slightly yellowish fluid simulates closely on analysis, blood serum or lymph. It is not urine. Microscopically the wall of the cyst is seen to be composed of dense fibrous tissue bearing numerous capillaries. Frequently one sees areas which presumably represent occluded arterioles. In several of the sections of our own material numerous collecting tubules appear in the cyst wall. Such tubules bear a definitely flattened epithelium. No sclerosed glomeruli can be made out. In one case smooth muscle fibers are present in the wall of the cyst. Such fibers might have origin either in a portion of the pelvis or in the spiral muscle of the papilla. Such observations suggest the renal medulla as the site of origin of the cyst rather than the cortex.
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The cyst walls are lined by flattened epithelial cells, often poorly preserved, and occasionally showing infiltration by lymphocytes and plasma cells. In such a section the adjacent renal parenchyma is distorted by a chronic inflammatory process accompanied by considerable fibrosis. The glomerular tufts also are fibroid and occasionally hyaline. Sections of tissue taken a bit further from the cyst wall, however, show normal kidney. As a rule the large serous cyst of the kidney causes no especial symptoms, at least in its earlier existence while still small. It is most often discovered during palpation of the abdomen on physical examination, or as an incidental finding on abdominal section for some other lesion. In some instances the patient notes that the abdomen is increasing slowly in size, and though there is no pain, consults a physician for its explanation. On other occasions the patient notes only a sense of weight or discomfort in the loin. Such localizing symptoms as may occasionally be present are often due to interference by pressure of the cyst on the intestinal tract, stomach, or biliary passages. Frequently also the signs and symptoms of an acute or subacute pyelitis and cystitis cause the patient to seek medical advice. That secondary infection of a kidney bearing a large cyst should be common is to be assumed because of the ease with which such a formation may interfere with normal renal drainage by causing ptosis by its weight or by locally distorting the normal arrangement of pelvis or calices. As noted above the most common site for these cysts is at or near the lower pole of the kidney. Occasionally, however, they are found at the upper pole on the right side between kidney and the under surface of the liver. Because of this location their diagnosis may be quite obscure and their symptoms unusual. Of the 7 instances of solitary renal cyst which have come to operation in this hospital 4 have happened to be situated at the upper pole of the right kidney. Since the symptoms in these cases have been strikingly different from those usually ascribed to solitary cysts in general they will be discussed in detail. Case 1. A married woman 41 years old, a school teacher, entered the Brigham Hospital on October 6, 1927, complaining of a dull aching pain just below the right costal margin, which had been present intermittently for two years. During this time she had had three attacks of chills and fever, frequency of urination and pyuria. Though rest in bed relieved these attacks, the pain in the back persisted. On physical examination the lower pole of
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each kidney was palpable and there was tenderness on pressure anteriorly just under the right costal margin. Pyelograms showed normal well-filled pelves; cholecystograms were also normal. X-ray examination of the gastrointestinal tract, of the chest, and of the spine found nothing pathological. The urine contained only a few pus cells. An orthopedic consultant did not consider the pain due to bone or joint disease. She was discharged with a diagnosis of possible nephroptosis of the right kidney and slight urinary infection. On three subsequent hospital admissions for the same symptoms as above the same physical findings were present. Pelvic lavage was carried out without avail. On the fourth entrance to hospital a fitted corset and exercises were prescribed. An acute exacerbation of pain and chills togetb.er with frequency of urination caused her fifth admission. There was now found tenderness throughout the right flank most marked at the right costal margin and costo-vertebral angle. The right kidney was explored on April 21, 1928. A solitary cyst the size of a large hen's egg was found at the upper pole of the organ, slightly adherent to the under surface of the liver. The cyst was excised leaving a cone-shaped depression about 3 cm. in diameter in the parenchyma. There was no communication between the cyst and any portion of the renal pelvis. The edges of the wound in the kidney were approximated as closely as possible by interrupted sutures of fine catgut, the kidney replaced, and the wound closed. After operation, with the cessation of the cystitis in about 2 months, the patient was well and has remained so during the ensuing 4½ years. Case 2. A man 33 years old was referred to the hospital on the 30th of April, 1928, by Dr. Frederick W. Rice of Brighton. For several years he had had recurring attacks of pain in the right upper quadrant of the abdomen. There had been no urinary symptoms. These attacks had come on at intervals of about 3 months and usually had prevented work for about 2 days after which he had felt as well as ever. On the day of entrance the seizure began with severe frontal headache, malaise and slight abdominal discomfort. He was then awakened from sleep at 1 a.m. by severe non-radiating pain just below the margin of the ribs on the right, had a severe chill and subsequent fever. Examination showed fulness in the right abdomen, spasm of the right rectus muscle and a mass the size of two fists filling the upper part of the right abdomen. There was no costo-vertebral tenderness. He was immediately sent to hospital as an acute emergency and with a preoperative diagnosis of acute inflammation of the gall bladder with perforation was explored by Dr. Homans. A large retroperitoneal cystic tumor of the upper portion of the kidney was found which was punctured and drained through a second incision in the flank. After subsidence of the acute situation the cystic cavity as well as the renal pelvis was investigated by X-ray. The films demonstrated a large cyst 12 x 21 cm. above and internal to the pelvis which was seen dislocated and flattened. At a second operation on May 22, 1928, the large
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solitary cyst was excised. It had caused some torsion of the vascular pedicle and was found to communicate with the pelvis proper through an opening about 0.5 cm. in diameter. This opening was closed by a purse string suture and the parenchyma approximated by mattress sutures. Convalescence was
FIG. 1 FIG. 2 FIG. 1. Case 2. X-ray taken after injection of the cyst with sodium iodide solution. FIG. 2. Pyelogram of Case 2 showing outline of the solitary cyst and dilatation of the renal pelvis.
FIG. 3. Case 2. Photomicrograph (X75, reduced ½) of section of cyst wall sho,,-ing numerous collecting tubules.
uneventful, the infection remaining in the urinary tract on the right side responding readily to the usual measures. He has remained well during the subsequent 4 years. Microscopic report. Two sections representing a portion of the cyst wall show it to be composed of a fibrous tissue in which are found a number of
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tubules lined by a cuboidal type of cell. The cyst itself is lined by a flat cuboidal epithelium. Throughout this fibrous tissue there is a considerable infiltration of lymphocytes and plasma cells. In one section a portion of kidney substance is present which shows some of the chronic inflammatory process present in the walls. Many of the glomeruli in this portion show some hyaline change of the tufts and a slight thickening of Bowman's capsule. A few are fibrosed. They all are more or less distorted by the cyst wall.
FIG. 4. Case 2. Photomicrograph (X86, reduced½) of section of cyst wall showing chronic inflammatory process and occasional bundles of smooth muscle fibers.
FIG. 5. Case 2. Photomicrograph (X250, reduced½) of section of cyst wall showing compressed collecting tubules and chronic inflammation.
Case 3. A man of forty came to the hospital on December 12, 1932, complaining of chills, fever, dysuria, frequency of urination, and hematuria during the previous 16 days. Examination showed tenderness in the right flank and below the right costal margin anteriorly. The kidney could not be felt. The urine contained a little pus. Pyelography showed the renal pelvis deformed and pushed downward by a mass in the upper polar region of the kidney. A preoperative diagnosis of renal neoplasm was made but at operation the tumor
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was found to consist of a thin-walled cyst attached to the kidney at its upper pole. The cyst, about 5 cm. in diameter, was excised. No communication with the renal pelvis was present. Convalescence was normal and the patient was discharged 10 days later. Seen 11 months later he was well and had gained 30 pounds in weight. Pyelograms taken at this time showed that the pelvic outline, previously deformed, had resumed its normal configuration. Case 4. This 60-year-old man was seen on June 22, 1933, complaining of hematuria. He stated that about a year before, his urine had been bloody for 2 days. Following this he noted considerable shortening of the intervals of urination both day and night. A month before entrance he had had another attack of bleeding. Fhysical examination showed a man in excellent physical condition except for a slight cardiac enlargement and some increase in the
FIG.6 FIG. 7 FrG. 6. Case 3. Pyelogram before operation showing marked deformity of the upper portion of the pelvis. FIG. 7. Case 3. Pyelogram taken 10 months after operation showing normal outline of the renal pelvis.
size of the prostate. The urine was normal. Pyelography, however, discovered a cyst 7 cm. in diameter which was filled by the opaque medium casting a rounded shadow in the upper region of the pelvic outline. At operation the upper outer aspect of the kidney was found occupied by a cyst containing nearly 1500 cc. It was so closely incorporated with the parenchyma and dipped so deeply down into it that its excision was impossible; accordingly the kidney was removed. The patient was well when seen 4 months later. Gross description. Specimen consists of a kidney which weighs 150 grams. Projecting upon the middle of the convexity, a little toward the upper pole and slightly anterior of a mid-coronal section, there is a cyst 6.5 cm. in diameter. The wall is thin, opaque, membranous and pinkish-yellow. The remainder of the kidney surface appears normal. The capsule is thin and membranous. Coronal section shows an essentially negative kidney except for the deformity
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produced by the cyst. The inner wall of the cyst dips into the parenchyma as far as the level of the papillae in a sweeping hemi-spherical groove. The cyst communicates with one of the minor calices through a canal 1 mm. m
FIG.
FIG.
9. Case 4.
8. Case 4.
Pyelogram showing outline of the solitary cyst
Kidney removed at operation showing the solitary cyst in the upper
portion.
diameter and 5 mm. in length. The pelvis for the most part is pale white but there are numerous petechial hemorrhages within the mucosa in several areas. There is no infection. There is no appreciable increase in fat. The
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cortex is uniformly 7 mm. in thickness. The glomeruli can be seen but are not unusually prominent. The capsule strips with ease. The surface is smooth after stripping. There is no evidence of infection in the kidney substance. The cortical rays are well preserved. The medullary tissue is not remarkable except for the marked distortion produced by the cyst. The ureter is not remarkable. Microscopic rfport. The cyst of the kidney is lined by an imperfectly preserved, thin layer of epithelium. Immediately beneath the lining there is
FIG.10 FIG.11 FIG. 10. Case 4. Pyotomicrograph (X80, reduced ½) of section of cyst wall adjacent to kidney showing slight chronic inflammation in the cyst wall and the underlying normal renal parenchyma. FIG. 11. Case 4. Photomicrograph (X80, reduced ½) of communicating tract between cyst cavity and that of pelvis. (The partially denuded epithelium is an artefact.)
a zone of inflammation characterized by marked vascularity and chronic inflammatory cell infiltration. The renal parenchyma is not remarkable. The tubules contain hyaline and granular casts and much granular precipitate. The tubular epithelium shows only the usual post-operative degeneration. The glomeruli are not remarkable. None show arteriolar-sclerosis, capsular adhesions or capsular proliferation. There are no foci of round cells. The renal pelvis contains areas of hemorrhage and round cell infiltration. Serial sections through the small tract leading from the cyst to the calyx show at least one continuous passage, and possibly two, which is lined with transitional epithelium, and which is certainly preformed.
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An analysis of the symptoms of these cysts of the upper pole of the right kidney has been made from 32 cases found in the literature together with the 4 instances here reported. It is interesting to note a distinct tendency toward similarity. Over half these cases had pain in the right upper quadrant of the abdomen under the costal margin. This pain usually did not radiate. A few patients complained only of discomfort in this area. In a quarter of the cases the complaint was of pain in the right side of the back. In a few of these the pain radiated anteriorly, and in a few also, down the course of the ureter. In a third of the cases there were symptoms of cystitis and in a third also chills and fever were reported. Seven instances of gross hematuria are noted. In two-thirds of the group neither the kidney nor any tumor mass could be felt. When palpable it usually was so abdominally; not bimanually. Very few patients complained of tenderness on palpation. In about two-thirds of the cases, therefore, the physical examination was entirely negative. Laboratory examination showed that the urine was normal in about two-thirds of the cases reported. Pyelography in the 8 cases where it was performed gave the most accurate information, showing a deformity or displacement of the upper calices in 75 per cent of the cases. In reviewing a large number of solitary cysts of the kidney situated at other sites than the upper pole of the right kidney, we have found that in 41 cases where pyelography is recorded, 34 cases, or 83 per cent, showed abnormal pyelograms. Braasch and Carman and Herbst and Vynalek have reviewed the changes found by pyelography in cases of solitary cysts of the kidney. The most constant changes are shortening of the calices adjacent to the cyst, flattening of the portion of the true pelvis nearest to the cyst, filling defect, actual outline of the cyst, and changes in the axis of the kidney caused by the weight of a cyst situated at either pole. Accurate preoperative diagnosis of cysts of the upper pole of the right kidney has rarely been made. Only 1 of our 4 and 5 of 30 reported cases were diagnosed correctly. A diagnosis of cholecystitis was made in 9 cases. In 1 of these a ruptured gall bladder was suspected, and in 2 others jaundice due to obstruction of the common bile duct from pressure of the cyst was present. In the cases where pyelograms were made
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the diagnosis was usually tumor of the kidney; the benign cyst being found at operation. In 1 of the cases a renal stone was suspected. The above symptoms found in the cases of solitary cysts of the upper pole of the right kidney are quite in contrast to the lack of symptoms usually caused by this condition, for the cyst of the lower pole of the kidney rarely produces outstanding symptoms. As noted above, the patient with a cyst in this location usually complains of a painless palpable tumor mass or the abdominal tumor is found on physical examination. Although a solitary cyst of the upper pole of the right kidney is a rare occurrence, one must consider it in the differential diagnosis of the cause of pain in the right upper quadrant, especially in those cases where the gall bladder has been found to be normal by cholecystographic studies. Pyelography is the most accurate means of diagnosis of a solitary cyst of the kidney. REFERENCES (1) ABEL, I.: Solitary cyst of the kidney. Report of a case with review of the literature. Urol. and Cutan. Rev., 1916, xx, 617-621. (2) ALBERT: quoted by W. CALHOUN STIRLING: Large solitary hemorrhagic renal cyst with review of the literature. Report of a case. Jour. Urol., 1931, xxv, 213-222. (3) BREWER, G. E.: Simple cyst of the kidney. J our. Amer. Med. Assoc., 1908, 1, 718. (4) CUNNINGHAM, J. H.: Large solitary and multiple cysts of the kidney. Surg., Gynec. and Obstet., 1916, xxiii, 688-696. (5) DAMM, E.: Solitarcysten der Niere. Ztschr. f. urol. Chir., 1932, xxxv, 102-113. (6) DELKESKAMP, G.: Beitrage zur Nierenchirurgie. Beitr. z. klin. Chir., 1904, xliv, 1-139. (Case report on p. 58.) (7) DODSON, A. I.: Cysts of the kidney. South. Med. Jour., 1933, xxvi, 223-231. (8) D6zsA, E.: Klinische Beitrage zu den grossen serosen Cysten der Niere. Ztschr. f. urol. Chir., 1927, xxii, 70-80. (9) FULLERTON, A.: Solitary cysts of the kidney. Brit. Jour. Surg., 1927, xiv, 629-633. (10) HARPSTER, C. M., BROWN, T. H. AND DELCHER, A.: Solitary unilateral large serous cysts of the kidney with report of two cases and review of the literature. Jour. Urol., 1924, xi, 157-175. (11) HERBST, R. H. AND VYNALEK, W. J.: Solitary serous cysts with study of the X-ray observations. Jour. Amer. Med. Assoc., 1931, xcvi, 597-602. (12) HIGGINS, C. C.: Solitary cysts of the kidney. Ann. Surg., 1931, xciii, 868-879. (13) HOFER, 0.: Choledochusverschluss und Anurie
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(18) MrnET, M . H.: Kyste hematique perirenal et hydronephrose. Jour. d'urol. Med. et chir., 1921, xi, 581-585. (19) PETTINARI, V.: Contributo alla conoscenza delle cisti solitarie del rene. Arch. ital. di urol., 1929, v, 305-348. (20) PUGH, W. S.: Resection of kidney for solitary cyst. Surg. Clin. No. Amer., 1932, xii, 373-376. (21) RECAMIER: Kyste sereux du rein. Extirpation de la portion libre de la poche. Guerison. Ann. d . rnal. gen. d. org. genito-urin., 1893, xi, 185-187. (22) SECRETAN, M.: Grands kystes du rein. Jour. d'Urol., 1929, xxvii, 5-10. (23) SrMONCELLI, G.: Contributo clinico allo studio delle grandi cisti sierose del rene. Policlin. sez. chir., 1924, xxxi, 105-113. (24) SMITH, L. D.: Solitary serous renal cysts. Illinois Med. Jour., 1927, lii, 291-295. (25) SouLIGoux AND GouGET: Contribution a l'etude des grands kystes hematique simples du rein. Arch. gen. de med., Avril 4, 1905. (26) SWEETSER, H.B.: Large infected solitary cyst of the kidney. Minnesota Med., 1929, xii, 786-788. (27) THOMAS, B. A.: Enormous solitary cyst of the kidney associated with pyonephrosis. Case report. Jour. Urol., 1927, xviii, 528-530. (28) TuFFIER, M.: De l'ablation par dissection des grands kystes sereux du rein. Arch. gen. de med., 1891, ii, 5-13. (29) VrETHEN, H.: Ein Fall von Solitarcyste bei Hufeisenniere. Zentralbl. f. Chir., 1926, liii, 2655-2657. (30) VOGEL: Beitrage zur Nierenchirurgie. Zwei Falle von Nierencyste. Zentralbl. f. Chir., 1912, xxxix; 1540-1544. (31) WULFF, 0 .: Uber Solitare, von Hamaturie begleitete Blutcysten in den Nieren. Arch. f. klin. Chir., 1915, cvi, 689-698. Other References (32) BRAASCH, W. F. AND CARMAN, R. D .: The pyelographic and roentgenologic diagnosis of renal tumors. Collected papers of the. Mayo Clinic and the Mayo Foundation, 1924, xvi, 327-339. (33) BRANCH, C. F. : Some observations on solitary cysts of the kidney. Jour. Urol., 1929, xxi, 451-453. (34) BRIN, M. H.: Des kystes non hydatiques du rein. W. Rapport et Inform. Assn. Franc. d'Urol., 1911, xv, 33- 234. (35) CARSON, W. J.: Solitary cysts of the kidney. Ann. Surg., 1928, lxxxvii, 250-256. (36) COLSTON, J. A. C.: Solitary cyst and papillary cystadenoma occurring simultaneously in one kidney. Jour. Urol., 1928, xix, 285-290. (37) GRUBER, G. B.: Morphologie der Missbildungen der Menschen und der Tiere. Schwalbe- Jena, 1927, iii Teil, xii Lief. S. 193. (38) HEPLER, A. B.: Solitary cysts of the kidney. A report of seven cases and observations on the pathogenesis of these cysts. Surg., Gynec. and Obstet., 1930, 1, 668- 687. (39) KAMPMEIER, 0. F.: A hitherto unrecognized mode of origin of congenital renal cysts. Surg., Gynec. and Obstet., 1923, xxxvi, 208-216. (40) LATTER!, S.: Le cisti solitarie sierose del rene. Studio clinico, anatomopatologicco e sperimentale. Arch. ital. di. urol., 1930, vi, 113-157. (41) McKIM, G. F. AND SMITH, P . G.: Solitaryserouscystsofthekidney. Jour. Urol., 1924, xii, 635-
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(43) REINECKE: Solitare vielkammerige Cyste der Niere. Virchow's Arch. f. path. Anat., 1925, ccliv, 425-438. (44) SrMKow, A.: Les grands kystes sereux der rein. (Etude clinique et chriurgicale) These de Paris. Jouve et Cie., 1932, no. 362, 87. (45) VoNACHER, J. R. AND SPRENGLER, A.: Solitary cysts of the kidney. Report of case. Illinois Med. Jour., 1927, li, 413-415.
DISCUSSION DR. W. F. BRAASCH (Rochester, Minn.): Drs. Quinby and Bright have called our attention to a very interesting symptom complex occurring with solitary cysts of the kidney. Although this condition is usually symptomless, occasionally the cyst increases in size to such an extent that it causes distress or obstructs renal drainage. Secondary infection of the cyst is occasionally observed, with resulting fever and pain. Hematuria is sometimes observed but it is usually of no serious significance. The cyst may occasionally increase rapidly in size and cause pressure atrophy of the adjacent renal tissue. Such atrophy, however, rarely is so extensive as to seriously damage renal function. Surgical interference may be necessary with these complications, but in most cases the uncomplicated cyst needs no treatment. However, the difficulty of clinical differentiation between a simple cyst and neoplasm is the usual cause for surgical exploration, and in fact makes such exploration necessary in almost every case of renal cyst. Although there are definite clinical and urographic data which differentiate simple renal cyst from renal neoplasm, nevertheless the data are often quite similar and clinical differentiation may be impossible without surgical exploration. In attempting clinical differentiation it may be stated that simple renal cysts usually exist many years without the patient being aware of them. In fact, they are often observed by the patient and known to have remained stationary for years. Unfortunately, the same data may occur with tumor of the kidney. This is also true with regard to the rate of growth, since both simple cyst and neoplasm occasionally increase rapidly in size. It is not possible to differentiate between them by palpation alone. It will be possible to differentiate simple cyst from neoplasm by means of urography in most cases, but not in all. The following urographic data are usually observed with simple cyst: (1) abbreviation of the adjacent calices; (2) compression and :flattening of the adjacent portion of the renal pelvis; and (3) change in position and axis of the kidney as the result of tumor in one pole. The outline of a simple cyst may be visible adjacent to that of the renal pelvis and its relation to the pelvic deformity may be of value in its identification.