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The Significance of Renal Displacement
THE JOURNAL O:F' UROLOGY
Vol. 76, No. 5, November 1956 Printed in U.S.A.
THE SIGNIFICANCE OF RENAL DISPLACEMENT WILLIAM J. ENGEL From the Department of Urology, The Cleveland Clinic Foundation, and The The Frank E. Bunts Educational Instit1,te, Cleveland, Ohio
Displacement of the kidney, or the renal pelvis, from its normal position may be a finding of importance in arriving at a correct diagnosis. It is determined by roentgen examination and may be observed on the plain film or more frequently by means of intravenous or retrograde pyelography. This finding has not been accorded much attention in medical literature. Our experience is presented to indicate the diagnostic importance of this finding and to stimulate further observations. In this discussion we are concerned only with displacement of the kidney from its normal position and will not consider abnormal renal mobility as manifested by renal ptosis, or congenital malposition such as renal ectopia and congenital malrotation. Renal displacement not only should be noted during inspection of existing films, but should be sought for by roentgenograms specifically ordered for this purpose. It is advisable to do a urogram in all patients with unidentified abdominal masses since it is impossible to determine their exact nature and location by physical examination alone. Renal displacement is strong evidence of retroperitoneal tumor. Schulte and Emmett 1 reported renal displacement in 72 ..5 per cent of retroperitoneal tumors on urographic examination, and De Weerd 2 reported displacement of the kidney or ureter in 73 per cent of lipomatous retroperitoneal tumors studied by urographic means. It will be pointed out later than renal displacement is not pathognomonic of retroperitoneal tumor, a fact which should be noted in this connection. All cases of suspected adrenal tumor should likewise have the benefit of an intravenous urogram. Poutasse 3 recently reported on roentgen studies of patients with adrenal disease seen at our clinic. Thirteen nonhormonal adrenal tumors were demonstrated by intravenous urography and renal displacement was demonstrated by urography in three out of four cases of Cushing's syndrome found to be due to adrenal tumor. However, only one of five patients with proven pheochromocytoma showed any degree of renal displacement on the urogram. This is explained by the fact that many of these tumors are too small to cause renal displacement and some may be obscured by the renal shadow. Kaplan and Greene 4 studied the urogran1s on 72 patients with Huspected adrenal tumors. In 31 of these there was evidence of renal displacement and 29 of these were proved to have an adrenal tumor at subsequent smgical exploration. Read at annual meeting, American Urological Association, Boston, Yiass., May 28, 1956. 1 Schulte, T. L. aud Emmett, J. L.: Urography in differential diagnosis of retroperitoneal tumors. J. Urol., 42: 215-219, 1939. 2 De Weerd, J. H.: Lipomatous retroperitoneal tumors: nrographic findings. J. Urol., 71: 421-426, 1954. 3 Poutasse, E. F.: Value and limitation of roentgenographic diagnosis of adrenal di,ease. ,J. Urol., 73: 891-900, 1955. 1 Kaplan, ,J. H. and Greene, L. F.: Urographic findings in cases of tumor of ,rnprarenal gland. Surg. Clin. North Amer., 28: 1071-1078, 1948. 478
RIGNIFICANCE OF 1-tl
479
Displacement of the left kidney may be a helpful point in ,mspected tumor or eyst of the pancreac1. The urogram may also reveal displacement of the kidney or ureter in patients with obscure pelvic or abdominal pain due to retroperitoneal lymph node involvement. In cases of accidental injury, displacement of the kidney may help to identify retroperitoneal bleeding, and displacement with fixation of the kidney may be an aid in the diagnosis of perinephric abscess. Abnormal position of the kidney or the renal pelvis may be due to intrinsic or extrinsic causec1. Extrarenal lesions produce displacement of the entire renal mass. Intrinsic, lesions, notably large cysts and tumors, may also displace the entire kidney, especially if they are situated on the medial aspect of the kidney. It will be pointed out that certain intrinsic: lesions may displace only the renal pelvi8 while the renal mass remainc1 in its normal relationship to adjacent struc tures. '\Ve believe that a distinction should be made between abnormal position of the renal pelvic1 and true deformity though we admit that at times th;; distinction may he quite difficult . .\NATOMIC CONSIDERATIONS
The kidneys Jie one 011 each side of the Yertebral column in a deepened hollow and are supported by the perirenal fascia and the enclosed fatty covering. The only true attachment of the kidneys is by means of the vesc1cls of the renal pPdicle. Dic1placement 18 possible in any direction except posteriorly where they lie against the costal cage and the heavy muscle8 of the back. There is some resistance to direct medial movement because of the vertebral column and the p8mrn muscle. 1Vith the pedicle as a fixed pivotal point, outward displacement of the upper or lower pole will cause the kidney to rotate around the fixed central axic1 of the renal Yesc:elc1, which results in displacement of the long axis of the kidney. There is considerable normal variation in the position of the kidneys. are relati\·ely mobile, move with respiration, and varying degrees of matic ptofiis will occur. Thec1e facts must ahvays he considered when interprr'.ting abnormal position. 1Ye revie\Yed a series of normal urograms to obtain c1ome sort of a base line from which to judge abnormal pm,ition. We checked the relationship of the long axi;; of the renal mass to the midline of the spine and to the psoas shadow and also the long axis of the renal pelvis (from superior to inferior . With few exceptions the long axis of the kidney runs obliquely a,rny from the rnidlinc at about 20 degrees and ic1 generally parallel to the psoas shadmv (plus or minus fi degrees). Thr long axis of the pelvis is not always identical with that of the renal mass and c1hom, a some,1·hat greater variation in relatio11 to its angle ,Yith the midlinc. The long axifi of the kidney varies 11·ith the prominence of tlw p:-;oac1 muscle aud 1Yith itc1 position in relation to this muscle. The high lying kidneys become more ,·erhcal becalrne they are aboYe the psoas muscle and their po,,ition i:-< determined more by the vertebral column. 111 general, the two kidneys tend to be c1ymrnetriraL In the series of normal urog;rams ,d.udied there ,nm c1ome variation in the distance of the lmYer poh·
480
WILLIAM J. ENGEL
FIG. 1. A, example of obvious renal displacement by extrinsic mass. Generally speaking;, displacement of kidney indicates retroperitoneal lesion. B, photograph of primary unattached retroperitoneal tumor removed from this patient.
from the midline which is often exaggerated if a pressure bag over the lower abdomen is employed. It is significant however that in no normal case did we observe an instance in which the upper pole was displaced away from the midline. When this variation appears it should therefore be regarded as significant. Normally the right kidney is lower than the left, although the reverse may be true. In a recently published study McClellan 5 noted that the left kidney was lower than the right in 106 of 1500 urograms reviewed (7.1 per cent). Twentynine of these could be attributed to specific disease or anatomic abnormality leaving 77 cases unexplained. Thus in only 5.1 per cent of cases was the left kidney considered to be "normally" lower than the right. The incidence is therefore small enough that when the left kidney is lower, the fact should be noted as possibly significant. Renal displacement may be minimal; moderate (meaning that it is obvious by even casual inspection of a film); or it may be extreme. Moderate or obvious displacement has many causes with which most of us are familiar; therefore these cases deserve no detailed consideration here. Our experience in this group of cases justifies certain generalizations. 1) There is no typical displacement which can be regarded as diagnostic of a particular cause. 2) Displacement of the kidney denotes a retroperitoneal mass (fig. 1) with certain exceptions which will be noted later. 3) The direction of the displacement limits the number of probable causes and a careful clinical history further reduces the possibilities. 4) Consider5
McClellan, R. E.: A low lying left kidney. J. Ural., 75: 198-199, 1956.
SIGNIFICANCE OF RENAL DISPLACEMENT
481
Fm. 2. Extreme displacement of kidney. Left kidney overlies right kidney. Large retroperitoneal cystic fibroma was removed from this patient.
able displacement of the kidney may be present in the absence of a clearly palpable abdominal mass. Extreme displacement is a descriptive term we have reserved for those instances in which the kidney from one side has been displaced to such an extent that it comes to lie on the opposite side of the body (fig. 2). We have seen three examples of this and in each instance it was produced by an unattached retroperitoneal tumor which was benign in two cases (an epithelial cyst and a cystic fibroma) and a very low-grade fibrosarcoma in the third. This is in keeping with similar cases reported by Greene, 6 all three of which were benign retroperitoneal tumors. Two useful facts seem to emerge. 1) That extreme displacement indicates an essentially benign tumor as its cause; and 2) it indicates an operable rather than an inoperable tumor. In two of our cases studied by intravenous urography after operation, the kidney has spontaneously returned to its normal location. Greene reported the same experience. We are here chiefly concerned with the diagnostic significance of minimal displacement of the kidney or the renal pelvis. For want of a more satisfactory definition of this term we might describe it as that degree of displacement which might escape recognition or be disregarded. These are the cases which justify this presentation and there is one particular group of cases to which we wish to draw attention. We have pointed out that a distinction should be made between displacement of the kidney (the entire renal mass) and displacement, or perhaps more properly 6 Greene, L. F: Extreme renal displacement due to retroperitoneal tumors. J. Urol., 59: 174-178, 1948.
482
WILLIAM J. ENGEL
abnormal position, of the renal pelvis. Thus the renal pelvis, or its upper calyces, may assume an abnormal or atypical position even though the renal mass retains essentially normal relationships. This occurs with one of the anomalies and is in many cases sufficiently characteristic to be diagnostic. This anomaly is duplex kidney with complete iireteral dilplication associated with an ectopic iireteral or~fice to the ureter going to the upper pelvis. In this situation the upper pelvis is frequently hydronephrotic and infected and renal function of this portion of the kidney is so impaired that there is no excretion of the contrast medium administered for intravenous urography. The lower portion of the kidney, whose ureter empties normally into the bladder, retains normal function and visualizetl well. To the unwary this lower pelvis may present an apparently normal appearance (fig. :~) but viewed more critically one observes varying degrees of atypical displacement of the renal pelvis. In some only the upper calyx is deflected outward, sometimes ever so slightly (fig. 4). In more pronounced cases the lower pelvis will be displaced laterally from the midline but alwayH with a rather c:haracteriHtic: outward bending of the upper calyx (fig. 5). Commonly the lower pelvis will be smaller ·when compared with the opposite normal kidney (fig. 6). We have also observed as helpful signs some deviation of the normal ureter in its course from the lower pelvis to the bladder and in a few instances the dilated acceHsory ureter has produced a deformity of the bladder seen in the cystogram. If the shadow of the entire renal mass were always clearly visible the recognition of these rases would be easier, but frequently, especially in children, this
FrG. :3. A, right pyelogram and B, left pyelogram of 8-year-old girl whose complaint ,vas recurring fever and pyuri:1. Left pyelogram appears essentially normal but note displacement of uppercalycesawayfrom midlinewithslight outward bending. C, pyelogram obtained after catheterization of ectopic ureter found in urethra during second search. Patient entirely well 10 years after heminephrectomy.
Fm. 4. J, intrnvcnmrn urogrnm of Hl-year-olcl woman who complained of pcrsistfrnt, irritating vaginal disclrnrge present all her life. Note normal left kidnc,· pelvis. Uppc)I' on right is blunted and slight,]y displaced away from midline. B, ureterogram obt,ained ent.hetcrization of sm:dl ectopic ureteral orifice found in the vagina.
Fr<+. 5. cl, urogram of 3-,·ear-old girl whose comph1int, ,Ya.s recnrring fever and Right kidney normal. Note Lypic:tl outward displacement of left renal pelvis with bending of upper calyccs. Carnful search failed to disclose ectopic ureteral orifirr, lmt operation :u!vised on basis of "t 0·pical" pyelogrnm. B, gross specimen removed from t.hi, pat ieni" showed hydronephrotic ttpper pelvis and dilated ureter. 48:J
48--lc
WILLIAM J. E:"
FIG. 6. A, urogram of 32-year-old woman whose complaint was intermittent left lower quadrant pain and vaginal discharge.Note smaller left renal pelvis with very slight outward bending of upper calyces. B, ureteropyelogram obtained by catheterizing very small ectopic ureteral orifice found in vagina.
FIG. 7. A, urogram of 5-month-old female infant complaining of intermittent fever and pyuria. Note decided displacement of left renal pelvis outward and slightly downward. B, at time of cystoscopy an accidental ureteroscopy was accomplished. Roentgenogram shows cystoscope in ureter (which opened into urethra); hydroureter and hydronephrosis of upper pelvis clearly demonstrated.
SIGNIFICANCE OF RENAL DISPLACBMENT
185
FIG. 8. A, retrograde right pyelogram in 60-year-old man complaining of pain in right flank and subcostal region. Marked displacement of right renal pelvis thought to be dno to mass above kidney. B, photograph of gross specimen showing hydronephrosis of npper half of dl1plex kidney ·with hydroureter. Ectopic ureteral orifice later demonstrated in prostatic urethra.
is not the case. Furthermore there would be no problem in the diagnosis if the ectopic ureteral orifice could always be identified at cystoscopic or ntginal examination. I can testify, for myself at least, that this is not always pm,sible even with repeated meticulous examinations when one feels certain that such a condition exists. The condition occurs more commonly in children, girls especially, and ,\·ith one exception all children seen by us have been referred because of recurring bouts of fever and pyuria (fig. 7). The exception was the girl aged 19 ,vho rnmplained of a persistent, irritating vaginal discharge (fig. 4). The condition is not limited to children as we have seen it in adultc1, the oldest being 60 years of age (fig. 8). In two of the adults the diagnosis waci missed as we were not then aware of the diagnostic significance of this type of renal displacement. This roentgenographic sign of this anomaly should be familiar to all urologist:,; and roentgenologists alike as an important diagnostic finding. When typical, and in the presence of consistent clinical findings, surgical exploration is indicated.
486
WILLIAM J. ENGEL
Whenever possible the operation should be limited to the removal of the diseased upper part of the duplex kidney together with the dilated accessory ureter. Minimal displacement of the kidney may be observed due to other conditions. Small adrenal tumors may produce only minimal outward displacement of the upper pole or a minor degree of downward displacement. As mentioned previously a slight downward malposition of the left kidney should excite more suspicion because it is normally higher than the right. Other extrinsic lesions which should be considered in the presence of minor degrees of renal displacement are small, unattached retroperitoneal tumors, encysted retroperitoneal hematoma (if history of trauma is elicited), aortic aneurysm and, more rarely, a perinephric abscess. We have encountered patients with small renal cortical tumors and cysts producing no typical deformity of the renal pelvis but identified because they displaced the upper or lower pole of the kidney away from the midline. Early in my experience I had the impression that renal displacement was produced only by retroperitoneal masses. The error of this concept was soon established by the pyelogram shown in figure 9, in which surgical exploration proved the displacement to be due to pressure from a liver lobe. We have seen other examples of marked downward displacement of the right kidney by the liver and the left kidney by an enlarged spleen. Displacement of the kidney by the liver or spleen gives rise to a more or less typical "bent stem" or "lily of the
Fm. 9. Roentgenogram in anteroposterior and lateral oblique position showing typical "bent stem" displacement of kidney produced by liver lobe. Similar displacement has been seen on left side produced by splenomegaly.
SIGNlFIC,\ NCFJ OF HK'\ AL DTSPLc\C; l~MEN'J'
487
ntlley" appearance. There is no ddmmity of the calyces and strangely r~11ough which hydronephrosis wat> present. It t>hould be noted however that not all patients with c11largcmc11t of their liver or spleen will have renal displacement. Theoretieally one would not expect this to happen and one may suspeet that some adhesion mtist exist whieh attache:-i the kidney to the enlarging liver or spleen. Intra-abdominal tnmon-: do not wmally displace the kidney though we have seen a patient with a kiom,vosar<'oma of the stomach which displaced the left kidney.
,rn have 1-1een no case in
SUMMARY :\ND CONCLl:SIONS
Our observations indicate that there is some value in differentiating twtwccn displacement of the entire renal mass and displacement or abnormal position of only the renal pelvii-i. Cases arc cited to show that there is a fairly typical type of displacement of the renal pelvi1-1 which is associated with duplex kidney ·with hydronephrosis of the upper pelvis associated \Yith an ectopic ureteral orifi('e. The findings reported here naturally became more significant becau:-;e the patients were referred with ,;ymptoms of urinary tract diseases but the interpretation of auy roentgenogram is necessarily influenced by the clinical hi:-itory, physical examination and laboratory studies of the patient under observatiou. Renal displacement of and by itself is not diagnostic of any specific pathological entity but \Yhen present may be of great as8istance in aniving at a correct diagnosis. It may also influence the surgical management of the case. Displacement of the kidney generally denotes a rctroperitoncal mass as its eanse. Intraperitoneal tumorn rarely do so. Enlargement of the liYer or spleen rnay displace the kidney downward in a characteristic "bent stem" manner. The detection of abnormal position of the kidney or the renal peh'is is one of thoHe minor points in x-ray interpretation which may be an important clue to a correct diagnosi:s, which should always precede proper treatment.
Vol. 76, No. 5, November 1956 Printed in U.S.A.
THE SIGNIFICANCE OF RENAL DISPLACEMENT WILLIAM J. ENGEL From the Department of Urology, The Cleveland Clinic Foundation, and The The Frank E. Bunts Educational Instit1,te, Cleveland, Ohio
Displacement of the kidney, or the renal pelvis, from its normal position may be a finding of importance in arriving at a correct diagnosis. It is determined by roentgen examination and may be observed on the plain film or more frequently by means of intravenous or retrograde pyelography. This finding has not been accorded much attention in medical literature. Our experience is presented to indicate the diagnostic importance of this finding and to stimulate further observations. In this discussion we are concerned only with displacement of the kidney from its normal position and will not consider abnormal renal mobility as manifested by renal ptosis, or congenital malposition such as renal ectopia and congenital malrotation. Renal displacement not only should be noted during inspection of existing films, but should be sought for by roentgenograms specifically ordered for this purpose. It is advisable to do a urogram in all patients with unidentified abdominal masses since it is impossible to determine their exact nature and location by physical examination alone. Renal displacement is strong evidence of retroperitoneal tumor. Schulte and Emmett 1 reported renal displacement in 72 ..5 per cent of retroperitoneal tumors on urographic examination, and De Weerd 2 reported displacement of the kidney or ureter in 73 per cent of lipomatous retroperitoneal tumors studied by urographic means. It will be pointed out later than renal displacement is not pathognomonic of retroperitoneal tumor, a fact which should be noted in this connection. All cases of suspected adrenal tumor should likewise have the benefit of an intravenous urogram. Poutasse 3 recently reported on roentgen studies of patients with adrenal disease seen at our clinic. Thirteen nonhormonal adrenal tumors were demonstrated by intravenous urography and renal displacement was demonstrated by urography in three out of four cases of Cushing's syndrome found to be due to adrenal tumor. However, only one of five patients with proven pheochromocytoma showed any degree of renal displacement on the urogram. This is explained by the fact that many of these tumors are too small to cause renal displacement and some may be obscured by the renal shadow. Kaplan and Greene 4 studied the urogran1s on 72 patients with Huspected adrenal tumors. In 31 of these there was evidence of renal displacement and 29 of these were proved to have an adrenal tumor at subsequent smgical exploration. Read at annual meeting, American Urological Association, Boston, Yiass., May 28, 1956. 1 Schulte, T. L. aud Emmett, J. L.: Urography in differential diagnosis of retroperitoneal tumors. J. Urol., 42: 215-219, 1939. 2 De Weerd, J. H.: Lipomatous retroperitoneal tumors: nrographic findings. J. Urol., 71: 421-426, 1954. 3 Poutasse, E. F.: Value and limitation of roentgenographic diagnosis of adrenal di,ease. ,J. Urol., 73: 891-900, 1955. 1 Kaplan, ,J. H. and Greene, L. F.: Urographic findings in cases of tumor of ,rnprarenal gland. Surg. Clin. North Amer., 28: 1071-1078, 1948. 478
RIGNIFICANCE OF 1-tl
479
Displacement of the left kidney may be a helpful point in ,mspected tumor or eyst of the pancreac1. The urogram may also reveal displacement of the kidney or ureter in patients with obscure pelvic or abdominal pain due to retroperitoneal lymph node involvement. In cases of accidental injury, displacement of the kidney may help to identify retroperitoneal bleeding, and displacement with fixation of the kidney may be an aid in the diagnosis of perinephric abscess. Abnormal position of the kidney or the renal pelvis may be due to intrinsic or extrinsic causec1. Extrarenal lesions produce displacement of the entire renal mass. Intrinsic, lesions, notably large cysts and tumors, may also displace the entire kidney, especially if they are situated on the medial aspect of the kidney. It will be pointed out that certain intrinsic: lesions may displace only the renal pelvi8 while the renal mass remainc1 in its normal relationship to adjacent struc tures. '\Ve believe that a distinction should be made between abnormal position of the renal pelvic1 and true deformity though we admit that at times th;; distinction may he quite difficult . .\NATOMIC CONSIDERATIONS
The kidneys Jie one 011 each side of the Yertebral column in a deepened hollow and are supported by the perirenal fascia and the enclosed fatty covering. The only true attachment of the kidneys is by means of the vesc1cls of the renal pPdicle. Dic1placement 18 possible in any direction except posteriorly where they lie against the costal cage and the heavy muscle8 of the back. There is some resistance to direct medial movement because of the vertebral column and the p8mrn muscle. 1Vith the pedicle as a fixed pivotal point, outward displacement of the upper or lower pole will cause the kidney to rotate around the fixed central axic1 of the renal Yesc:elc1, which results in displacement of the long axis of the kidney. There is considerable normal variation in the position of the kidneys. are relati\·ely mobile, move with respiration, and varying degrees of matic ptofiis will occur. Thec1e facts must ahvays he considered when interprr'.ting abnormal position. 1Ye revie\Yed a series of normal urograms to obtain c1ome sort of a base line from which to judge abnormal pm,ition. We checked the relationship of the long axi;; of the renal mass to the midline of the spine and to the psoas shadow and also the long axis of the renal pelvis (from superior to inferior . With few exceptions the long axis of the kidney runs obliquely a,rny from the rnidlinc at about 20 degrees and ic1 generally parallel to the psoas shadmv (plus or minus fi degrees). Thr long axis of the pelvis is not always identical with that of the renal mass and c1hom, a some,1·hat greater variation in relatio11 to its angle ,Yith the midlinc. The long axifi of the kidney varies 11·ith the prominence of tlw p:-;oac1 muscle aud 1Yith itc1 position in relation to this muscle. The high lying kidneys become more ,·erhcal becalrne they are aboYe the psoas muscle and their po,,ition i:-< determined more by the vertebral column. 111 general, the two kidneys tend to be c1ymrnetriraL In the series of normal urog;rams ,d.udied there ,nm c1ome variation in the distance of the lmYer poh·
480
WILLIAM J. ENGEL
FIG. 1. A, example of obvious renal displacement by extrinsic mass. Generally speaking;, displacement of kidney indicates retroperitoneal lesion. B, photograph of primary unattached retroperitoneal tumor removed from this patient.
from the midline which is often exaggerated if a pressure bag over the lower abdomen is employed. It is significant however that in no normal case did we observe an instance in which the upper pole was displaced away from the midline. When this variation appears it should therefore be regarded as significant. Normally the right kidney is lower than the left, although the reverse may be true. In a recently published study McClellan 5 noted that the left kidney was lower than the right in 106 of 1500 urograms reviewed (7.1 per cent). Twentynine of these could be attributed to specific disease or anatomic abnormality leaving 77 cases unexplained. Thus in only 5.1 per cent of cases was the left kidney considered to be "normally" lower than the right. The incidence is therefore small enough that when the left kidney is lower, the fact should be noted as possibly significant. Renal displacement may be minimal; moderate (meaning that it is obvious by even casual inspection of a film); or it may be extreme. Moderate or obvious displacement has many causes with which most of us are familiar; therefore these cases deserve no detailed consideration here. Our experience in this group of cases justifies certain generalizations. 1) There is no typical displacement which can be regarded as diagnostic of a particular cause. 2) Displacement of the kidney denotes a retroperitoneal mass (fig. 1) with certain exceptions which will be noted later. 3) The direction of the displacement limits the number of probable causes and a careful clinical history further reduces the possibilities. 4) Consider5
McClellan, R. E.: A low lying left kidney. J. Ural., 75: 198-199, 1956.
SIGNIFICANCE OF RENAL DISPLACEMENT
481
Fm. 2. Extreme displacement of kidney. Left kidney overlies right kidney. Large retroperitoneal cystic fibroma was removed from this patient.
able displacement of the kidney may be present in the absence of a clearly palpable abdominal mass. Extreme displacement is a descriptive term we have reserved for those instances in which the kidney from one side has been displaced to such an extent that it comes to lie on the opposite side of the body (fig. 2). We have seen three examples of this and in each instance it was produced by an unattached retroperitoneal tumor which was benign in two cases (an epithelial cyst and a cystic fibroma) and a very low-grade fibrosarcoma in the third. This is in keeping with similar cases reported by Greene, 6 all three of which were benign retroperitoneal tumors. Two useful facts seem to emerge. 1) That extreme displacement indicates an essentially benign tumor as its cause; and 2) it indicates an operable rather than an inoperable tumor. In two of our cases studied by intravenous urography after operation, the kidney has spontaneously returned to its normal location. Greene reported the same experience. We are here chiefly concerned with the diagnostic significance of minimal displacement of the kidney or the renal pelvis. For want of a more satisfactory definition of this term we might describe it as that degree of displacement which might escape recognition or be disregarded. These are the cases which justify this presentation and there is one particular group of cases to which we wish to draw attention. We have pointed out that a distinction should be made between displacement of the kidney (the entire renal mass) and displacement, or perhaps more properly 6 Greene, L. F: Extreme renal displacement due to retroperitoneal tumors. J. Urol., 59: 174-178, 1948.
482
WILLIAM J. ENGEL
abnormal position, of the renal pelvis. Thus the renal pelvis, or its upper calyces, may assume an abnormal or atypical position even though the renal mass retains essentially normal relationships. This occurs with one of the anomalies and is in many cases sufficiently characteristic to be diagnostic. This anomaly is duplex kidney with complete iireteral dilplication associated with an ectopic iireteral or~fice to the ureter going to the upper pelvis. In this situation the upper pelvis is frequently hydronephrotic and infected and renal function of this portion of the kidney is so impaired that there is no excretion of the contrast medium administered for intravenous urography. The lower portion of the kidney, whose ureter empties normally into the bladder, retains normal function and visualizetl well. To the unwary this lower pelvis may present an apparently normal appearance (fig. :~) but viewed more critically one observes varying degrees of atypical displacement of the renal pelvis. In some only the upper calyx is deflected outward, sometimes ever so slightly (fig. 4). In more pronounced cases the lower pelvis will be displaced laterally from the midline but alwayH with a rather c:haracteriHtic: outward bending of the upper calyx (fig. 5). Commonly the lower pelvis will be smaller ·when compared with the opposite normal kidney (fig. 6). We have also observed as helpful signs some deviation of the normal ureter in its course from the lower pelvis to the bladder and in a few instances the dilated acceHsory ureter has produced a deformity of the bladder seen in the cystogram. If the shadow of the entire renal mass were always clearly visible the recognition of these rases would be easier, but frequently, especially in children, this
FrG. :3. A, right pyelogram and B, left pyelogram of 8-year-old girl whose complaint ,vas recurring fever and pyuri:1. Left pyelogram appears essentially normal but note displacement of uppercalycesawayfrom midlinewithslight outward bending. C, pyelogram obtained after catheterization of ectopic ureter found in urethra during second search. Patient entirely well 10 years after heminephrectomy.
Fm. 4. J, intrnvcnmrn urogrnm of Hl-year-olcl woman who complained of pcrsistfrnt, irritating vaginal disclrnrge present all her life. Note normal left kidnc,· pelvis. Uppc)I' on right is blunted and slight,]y displaced away from midline. B, ureterogram obt,ained ent.hetcrization of sm:dl ectopic ureteral orifice found in the vagina.
Fr<+. 5. cl, urogram of 3-,·ear-old girl whose comph1int, ,Ya.s recnrring fever and Right kidney normal. Note Lypic:tl outward displacement of left renal pelvis with bending of upper calyccs. Carnful search failed to disclose ectopic ureteral orifirr, lmt operation :u!vised on basis of "t 0·pical" pyelogrnm. B, gross specimen removed from t.hi, pat ieni" showed hydronephrotic ttpper pelvis and dilated ureter. 48:J
48--lc
WILLIAM J. E:"
FIG. 6. A, urogram of 32-year-old woman whose complaint was intermittent left lower quadrant pain and vaginal discharge.Note smaller left renal pelvis with very slight outward bending of upper calyces. B, ureteropyelogram obtained by catheterizing very small ectopic ureteral orifice found in vagina.
FIG. 7. A, urogram of 5-month-old female infant complaining of intermittent fever and pyuria. Note decided displacement of left renal pelvis outward and slightly downward. B, at time of cystoscopy an accidental ureteroscopy was accomplished. Roentgenogram shows cystoscope in ureter (which opened into urethra); hydroureter and hydronephrosis of upper pelvis clearly demonstrated.
SIGNIFICANCE OF RENAL DISPLACBMENT
185
FIG. 8. A, retrograde right pyelogram in 60-year-old man complaining of pain in right flank and subcostal region. Marked displacement of right renal pelvis thought to be dno to mass above kidney. B, photograph of gross specimen showing hydronephrosis of npper half of dl1plex kidney ·with hydroureter. Ectopic ureteral orifice later demonstrated in prostatic urethra.
is not the case. Furthermore there would be no problem in the diagnosis if the ectopic ureteral orifice could always be identified at cystoscopic or ntginal examination. I can testify, for myself at least, that this is not always pm,sible even with repeated meticulous examinations when one feels certain that such a condition exists. The condition occurs more commonly in children, girls especially, and ,\·ith one exception all children seen by us have been referred because of recurring bouts of fever and pyuria (fig. 7). The exception was the girl aged 19 ,vho rnmplained of a persistent, irritating vaginal discharge (fig. 4). The condition is not limited to children as we have seen it in adultc1, the oldest being 60 years of age (fig. 8). In two of the adults the diagnosis waci missed as we were not then aware of the diagnostic significance of this type of renal displacement. This roentgenographic sign of this anomaly should be familiar to all urologist:,; and roentgenologists alike as an important diagnostic finding. When typical, and in the presence of consistent clinical findings, surgical exploration is indicated.
486
WILLIAM J. ENGEL
Whenever possible the operation should be limited to the removal of the diseased upper part of the duplex kidney together with the dilated accessory ureter. Minimal displacement of the kidney may be observed due to other conditions. Small adrenal tumors may produce only minimal outward displacement of the upper pole or a minor degree of downward displacement. As mentioned previously a slight downward malposition of the left kidney should excite more suspicion because it is normally higher than the right. Other extrinsic lesions which should be considered in the presence of minor degrees of renal displacement are small, unattached retroperitoneal tumors, encysted retroperitoneal hematoma (if history of trauma is elicited), aortic aneurysm and, more rarely, a perinephric abscess. We have encountered patients with small renal cortical tumors and cysts producing no typical deformity of the renal pelvis but identified because they displaced the upper or lower pole of the kidney away from the midline. Early in my experience I had the impression that renal displacement was produced only by retroperitoneal masses. The error of this concept was soon established by the pyelogram shown in figure 9, in which surgical exploration proved the displacement to be due to pressure from a liver lobe. We have seen other examples of marked downward displacement of the right kidney by the liver and the left kidney by an enlarged spleen. Displacement of the kidney by the liver or spleen gives rise to a more or less typical "bent stem" or "lily of the
Fm. 9. Roentgenogram in anteroposterior and lateral oblique position showing typical "bent stem" displacement of kidney produced by liver lobe. Similar displacement has been seen on left side produced by splenomegaly.
SIGNlFIC,\ NCFJ OF HK'\ AL DTSPLc\C; l~MEN'J'
487
ntlley" appearance. There is no ddmmity of the calyces and strangely r~11ough which hydronephrosis wat> present. It t>hould be noted however that not all patients with c11largcmc11t of their liver or spleen will have renal displacement. Theoretieally one would not expect this to happen and one may suspeet that some adhesion mtist exist whieh attache:-i the kidney to the enlarging liver or spleen. Intra-abdominal tnmon-: do not wmally displace the kidney though we have seen a patient with a kiom,vosar<'oma of the stomach which displaced the left kidney.
,rn have 1-1een no case in
SUMMARY :\ND CONCLl:SIONS
Our observations indicate that there is some value in differentiating twtwccn displacement of the entire renal mass and displacement or abnormal position of only the renal pelvii-i. Cases arc cited to show that there is a fairly typical type of displacement of the renal pelvi1-1 which is associated with duplex kidney ·with hydronephrosis of the upper pelvis associated \Yith an ectopic ureteral orifi('e. The findings reported here naturally became more significant becau:-;e the patients were referred with ,;ymptoms of urinary tract diseases but the interpretation of auy roentgenogram is necessarily influenced by the clinical hi:-itory, physical examination and laboratory studies of the patient under observatiou. Renal displacement of and by itself is not diagnostic of any specific pathological entity but \Yhen present may be of great as8istance in aniving at a correct diagnosis. It may also influence the surgical management of the case. Displacement of the kidney generally denotes a rctroperitoncal mass as its eanse. Intraperitoneal tumorn rarely do so. Enlargement of the liYer or spleen rnay displace the kidney downward in a characteristic "bent stem" manner. The detection of abnormal position of the kidney or the renal peh'is is one of thoHe minor points in x-ray interpretation which may be an important clue to a correct diagnosi:s, which should always precede proper treatment.