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The Nonvisualizing Kidney: A Pathologic Study of 83 nephrectomy Specimens
THE JOURNAL OF UROLOGY
Vol. 85, No. 2 February 1961 Copyright© 1961 by The Williams & Wilkins Co. Printed in U.S.A.
THE NONVISUALIZING KIDNEY: A PATHOLOGIC STUDY OF 83 KEPHRECTOMY SPECIMENS HARLAN J. SPJUT
AND
CHARLES H. NICOLAI*
From the Department of Surgery, Division of Surgical Pathology and Section on Urology, Washington University School of Medicine, Barnes Hospital and Barnard Free Skin and Cancer Hospital, St. Louis, Mo.
i
Together with clinical and laboratory data, the intravenous urogram plays an important role in the diagnosis of renal disease. Our interest in morphologically defining a nonvisualizing kidney was aroused by the pathological examination of nephrectomy specimens. Several kidneys appeared to be nearly normal or to contain large portions of parenchyma which appeared capable of functioning. Thus the question: -V\That, from the pathological standpoint, constitutes a nonvisualizing kidney? A kidney is referred to as nonvisualizing when there is no renal collecting system outline on rither the immediate (up to 30 minutes) or delayed (up to 8 hours) films taken after the intravenous injection of the urographic contrast medium. If only a retrogr:1de pyelogram was performed, those cases in ·1vhich no indigo carmine was excreted after 20 minutes were included in the category of nonvisualizing. The term nonvisualizing is not correctly interchangeable with the term nonfunctioning. Strictly speaking, arteriography is necessary to properly designate a kidney as nonfunctioning. However, in a clinical sense, a kidney which does not excrete enough contrast medium to permit visualization or enough indigo carmine for observation cystoscopically is considered nonfunctioning. Kidneys which are known to be nonvisualizing for periods of up to several months because of obstruction to the urinary outflow will return to near normal if the obstruction is removed. Also, kidneys considered nonfunctioning by arteriography because of vascular emboli may regain function following vascular recanalization. 1 Innumerable papers have been published regarding the clinical application of urography.
Little has been written concerning histopathological correlation with the clinical and urographic information. Strnndness 2 reviewed 70 cases of unilateral nonfunctioning kidney, Twenty ultimately had a nephrectomy; of these, the majority had renal lithiasis, carcinoma of the kidney or a congenital anomaly. Emmett and associates 3 studied 183 cases having atrophic kidneys but without an obvious etiological agent. Seventynine of these underwent nephrectomy, 51 of which were diagnosed as chronic atrophic pyelonephritis. The remainder were diagnosed a5 aplasia, hypoplasia and hypoplasia with chronic atrophic pyelonephritis. During the 5 year period of 1953-1957 inclusive, 255 nephrectomies were performed at Barnes Hospital. Of these, 83 (32.5 per cent) were urographically nonvisualizing kidneys. This number is not all inclusive as 17 other patients had nephrectomies ·without preceding "function" studies being performed; these are not included among the 83. Twelve of tbe 83 patients had a retrograde urogram without preceding intravenous urogram, but function studies were clone by employing indigo carmine dye administered intravenously. Kidneys failing to show function are included in the group of non visualizing kidneys. Fourteen cases with poor or longdelayed visualization of the removed kidney are not included. For purposes of this study, all available roentgenograms from the 255 cases and all of the histological reports and sections from the 83 nonvisualizing cases were reviewed. A minimum of 3 histologic sections were studied from each kidney. From the histologic material and the gross description of the resected nonvisualizing kidneys a crude estimate of function was made.
Accepted for publication April 11, 1960. * Present address: 607 N. Grand Blvd., St. Louis 3,Mo. 1 Hartman, G.: Die Bedentnng der Angiographie fi.ir Diagnostik und Therapie der sogenannten functionlosen Niere. :vinench. med. Wochnschr.,
2 Strandness, D. E, Jr.: The unilateral nonfunctioning kidney. Arch. Int. Med., 101: 611-619, 3 Emmett, J, L., Alvarez-Ierena, J. J. and McDonald, J. R.: Atrophic pyelonephritis versus congenital renal hypoplasia. J.A.M.A., 148: 1470-
101: 1264-1265, 19,59.
1477, 1952. 115
1958.
116
H. J. SPJUT AND C. H. NICOLAI TABLE
1. Major diagnostic groups
TABLE
2. Histologic diagnoses of nonvisualizing
kidneys
I
Pyelonephritis
Cancer
Other Diseases
'
Non visualizing kidney (83) ... 54 (65%) 7 (8.5%) 22 (26.5%) Visualizing kidney (172). 71 (41%) 62 (36%) 39 (23%) All kidneys (255) . 125 (49%) 69 (27%) 61 (24%)
This was based upon the amount of histologically or grossly normal appearing tissue in relation to diseased renal parenchyma. Except for a history of hypertension, known urinary tract obstruction, or history of trauma to the urinary tract, the historical data, physical examination, and clinical laboratory tests of the patient with a, nonvisualizing kidney gave no information that would categorically separate this patient from one with a visualizing kidney. Among the 83 patients there were 39 males and 44 females. Thirteen of the patients were children under the age of 15 years. The average age of the entire group was 45 years. The average age of the children was 3.3 years with an age range of 3 days to 14 years. The average age of the adults was 52 years with an age span of 17 to 77 years. From the pathological standpoint, pyelonephritis either in its acute or chronic form. was the most common histological lesion among the 255 nephrectomies (125 or 49 per cent). There were 69 (27 per cent) malignant tumors. Pyelonephritis was found in 65 per cent (54 cases) of the nonvisualizing kidneys, but there were only 7 (8.5 per cent) nonvisualizing kidneys with malignant tumors (table 1). The remammg pathologic diagnoses included dysplasia, renal artery aneurysm, infarction, arteriolonephrosclerosis, tuberculosis, trauma, and cysts of various sizes and numbers. The observations on pathologic entities do not pertain to the 13 children, admittedly a small group (table 2). Five of the nephrectomies for a nonvisualizing kidney were done in children for a dysplastic kidney,4 these usually being manifest as an intra-abdominal mass. Four of the 13 children had pyelonephritis. One of the four pyelonephritic kidneys exhibited focal dysplasia. In 4 Ericsson, N. 0. and Ivemark, B. I.: Renal dysplasia and pyelonephritis in infants and children. Arch. Path., 66: 2,55-263, 1958.
Histologic Diagnoses
Adults
Children
--------~~~1~---- -----
Pyelonephritis. Renal cell carcinoma. JVIetastatic carcinoma. Carcinoma of renal pelvis. Wilms tumor . Renal dysplasia. Granulom.atous diseases .. Trauma. Infarction . Arteriolonephrosclerosis ..
50 (71%) 4 4 (6%) 1 (1. 5%) 1 (1.5%) 1 3 (4.5%) 5 1 4 (6%) 1 (1.5%) 1 1 (i (9%)
(30.8%)
(7. 7%) (38.5%) (7. 7%) (7. 7%) (7. 7%)
addition, the kidney slwwing thrombosis of hilar vessels and extensive parenchymal infarction contained focal dysplastic areas. Thus, seven of the children's nephrectomy specimens revealed dysplasia,. In the total group of 255 ncphrectomies there were seven vVilms' tumors, but only one of these was nonvisualizing. Obstruction to the outflow of urine from the kidney prevents excretion of the contrast medium. 5 Venous and arterial obstruction is also an important factor. Of the 83 nonvisualizing kidneys, 62 had evidence of urinary drainage obstruction as shown by pyelocalicctasis or presence of a potentially obstructing lesion, such as a renal stone. Three of those 62 had major venous or arterial occlusion. Not all specimens with renal stones or other potentially obstructing lesions exhibited calyceal and pelvic dilatation. Eleven kidneys showed dilatation of the pelvis or calyces without clinical (or pathological) evidence of an obstructing lesion. Of the 83 nonvisualizing kidneys, 26 contained renal stones or had recently undergone nephrolithotomy; 22 others were associated with obstruction such as carcinoma of the bladder, advanced carcinoma of the uterine cervix, previous pelvic surgery, or inflammatory stenosis of the ureter at the ureteropelvic junction. The 8 kidneys diagnosed as renal dysplasia were not included in the obstructed group. An estimate of the function of an organ or part of an organ from the histological viewpoint cannot always be accurate. Slight deviations in the physiological or biochemical functions may not be reflected as altered histological findings. Thus our estimate of the function of a kidney from 5 Idbohrn, H.: Delayed excretion in urography and its significance. Acta radiol., 42: 1-10, 1954.
117
THE KONVISUALIZING KIDKEY
the histological and gross alterations is at best crude. This part of the study was done because, as had been previously stated, a number of nonvisualizing kidneys appeared to have a considerable amount of functionally intact parenchyma as determined from gross and histological considerations. Using the pathological features there were 5 (6 per cent) adult kidneys estimated to have 75 per cent or more functional parcnchyma. Four of these weighed within the normal range of 105 gm. to 195 gm. One weighed 380 gm. and had marked dilatation of the calyces and pelvis secondary to ureteral stenosis. Four of the 5 kidneys exhibited some degree of pelvic dilatation, although histologieally retaining a great deal of "functional" parenchyma. One kidney without dilatation of the pelvis or c:ilyces had a solitary abscess in the upper pole; the remainder of the kidney appeared normal. Twelve kidneys were estimated to have at least 50 per cent functional parenchyma. Three of the 12 (14.4 per cent) kidneys weighed less than 100 gm. The others were in the normal weight range for a single kidney except for one which contained a renal cell carcinoma. Six of the 12 kidneys displayed dilatation of the calyces and pd vis; six did not. The remaining 66 (79.6 per cent) kidneys had less than 25 per cent "functional" parenchyma. Forty had ealyceal and pelvic dilatation. Seventeen weighed less than 100 gm. The kidneys in this group ranged in weight from 8 gm. to 1550 gm. The latter was a severe chronic pyelonephritis with extensive xanthogranulomatous change. Thus it is evident that very few nonvisualizing kidneys are entirely normal. Even though a substantial amount of "functional" parenchyma may be present, obstruction to urinary outflow is often evident. This probably indicates that obstruction is an important basic factor in the pathogenesis of the nonvisualizing kidney. However, if a kidney is within the range of normal size by roentgen examination, the suggestion might be made that a moderate amount of "functional" parenchyma may be present and a more conservative management might be considered. (See Comments.) Stones were found in 26 of the nonvisualizing kidneys; none of the ncphrectomy specimens from children contained stones. Eleven of the stones were of the staghorn type. Eight stones were in the ureter or impacted in the ureteropelvic junction. Each of the 26 kidneys exhibited
pyelonephritis; one had a renal cell carcinoma and pyelonephritis. Of the 26 kidneys, 20 had less than 25 per cent "functional" parcnchyma, 5 had 50 per cent "functional" parem:hyma and one had 75 per cent. Among the 83 patients with nonvisualizing kidneys, there were 19 who had cxtrarenal conclitions which ultimately led to nephrectomy. The most frequent extrarenal cause for nephrectomy was carcinoma of the uterine cervix. Nine of these 19 patients had undergone therapy for this condition between a few weeks to 11 years earlier. In one patient recurrent carcinoma of the cervix was associated with metastases to the kidney. Another patient had a ureter severed during hysterectomy for carcinoma of the cervix. One had a retroperitoneal abscess complicating a 1Vertheim hysterectomy. The next most common extrarenal lesion contributing to poor kidney function was carcinoma of the urinary bladder. There were four such patients. One patient who had recurrent papillary carcinoma of the bladder underwent cystectomy and ilea! conduit diversion 6 years prior to nephrcctomy. Subsequently, urograms demonstrated a nonvisualizing kidney that proved by retrograde pyelography to contain an infiltrating transitional cell carcinoma of the pe1vis; severe acute and chronic pyelonephritis was noted on histological examination. The other 6 patirnts each had one of the following conditions which contributed to their renal disease: abdominoperineal resection of the sigmoid colon for carcinoma, transurethral and suprapubic prostatectomies (same patient), quadriplegia, pregnancy, traumatic renal laceration, and tuberculosis. Seven patients, other than the 19 just discussed, underwent nephrectomy following an evaluation which pointed to a renal etiology of their hypertension. Two of these had arteriolonephrosderosis, two had renal infarcts prrcccled by trauma to the kidney, one had thrombosis of the renal artery, one had chronic atrophic pyelonephritis and one had acute pyclonephritis. COMMENTS
Our study indicates that obstruction to urinary outflow is the most common (62 of 83 kidneys) basic pathogenic factor of the urographica.lly nonvisualizing kidney. This only serves to confirm the urographic observation that obstruction to
118
H. J. SPJUT AND C. H. NICOLAI
outflow of urine results in delayed or absent excretion of contrast medium. 5 Pyelonephritis in its acute and chronic form is the most common finding in nonvisualizing kidneys (54, or 65 per cent). In addition, pyclonephritis was associated with the dominant disease in 10 other nephrectomy specimens, e.g. in the four renal cell carcinomas and the carcinoma of the renal pelvis. Neoplasms accounted for less than 10 per cent of the nonvisualizing kidneys. A statistical comparison between the groups of visualizing and nonvisualizing kidneys demonstrated a statistical significance to the preponderance of pyelonephritis over neoplastic disease (x 2 = 22.6, P = 0.001). Since our group of children was small, no pertinent statements about the pathological findings could be made. However, only one of the 13 kidneys contained a neoplasm whereas nine of the kidneys were either dysplasia or pyelonephritis. Thus the trend is maintained. No entirely normal kidney was found among the nonvisualizing group. Twenty per cent of the 83 kidneys did have an abundant amount of normal appearing parenchyma. Most of these kidneys had dilatation of the ureter and pelvis indicating some obstruction to account for nonvisualization. Since one-fifth of the kidneys had a significant amount of normal parenchyma remaining, evaluation of the entire urinary tract should be performed prior to nephrectomy so
that renal tissue may be preserved by removing obstruction. Kidneys have a remarkable recuperative capacity following the removal of obstruction to the outflow of urine. 5 • 6 SUMMARY
A pathological and roentgenological review of 83 nonvisualizing kidneys was made in an attempt to define such a kidney. Obstruction to urinary outflow was present in 75 per cent of the kidneys and probably represents the basic factor accounting for nonvisualization. Fifty-four (65 per c.;ent) of the nonvisuarizing kidneys were pyelonephritic. Only 8.5 per cent of the kidneys contained a neoplasm. In children, pyelonephritis and dysplasia were the commonest causes of a nonvisualizing kidney. One-fifth of the nonvisualizing kidneys had an appreciable amount of normal appearing parenchyma. Other diseases among the nonvisualizing kidneys included arteriolonephrosclerosis, injury due to eirternal trauma, infarction, and granulomatous processes.
Surgical Pathology, Barnes IIosp., St. Louis 10, Mo. (H.J. S.) 6 Rolleston, G. L. and Reay, E. R.: The pelviureteric junction. Brit. J. Radio!., 30: 617-625, 1957.
Vol. 85, No. 2 February 1961 Copyright© 1961 by The Williams & Wilkins Co. Printed in U.S.A.
THE NONVISUALIZING KIDNEY: A PATHOLOGIC STUDY OF 83 KEPHRECTOMY SPECIMENS HARLAN J. SPJUT
AND
CHARLES H. NICOLAI*
From the Department of Surgery, Division of Surgical Pathology and Section on Urology, Washington University School of Medicine, Barnes Hospital and Barnard Free Skin and Cancer Hospital, St. Louis, Mo.
i
Together with clinical and laboratory data, the intravenous urogram plays an important role in the diagnosis of renal disease. Our interest in morphologically defining a nonvisualizing kidney was aroused by the pathological examination of nephrectomy specimens. Several kidneys appeared to be nearly normal or to contain large portions of parenchyma which appeared capable of functioning. Thus the question: -V\That, from the pathological standpoint, constitutes a nonvisualizing kidney? A kidney is referred to as nonvisualizing when there is no renal collecting system outline on rither the immediate (up to 30 minutes) or delayed (up to 8 hours) films taken after the intravenous injection of the urographic contrast medium. If only a retrogr:1de pyelogram was performed, those cases in ·1vhich no indigo carmine was excreted after 20 minutes were included in the category of nonvisualizing. The term nonvisualizing is not correctly interchangeable with the term nonfunctioning. Strictly speaking, arteriography is necessary to properly designate a kidney as nonfunctioning. However, in a clinical sense, a kidney which does not excrete enough contrast medium to permit visualization or enough indigo carmine for observation cystoscopically is considered nonfunctioning. Kidneys which are known to be nonvisualizing for periods of up to several months because of obstruction to the urinary outflow will return to near normal if the obstruction is removed. Also, kidneys considered nonfunctioning by arteriography because of vascular emboli may regain function following vascular recanalization. 1 Innumerable papers have been published regarding the clinical application of urography.
Little has been written concerning histopathological correlation with the clinical and urographic information. Strnndness 2 reviewed 70 cases of unilateral nonfunctioning kidney, Twenty ultimately had a nephrectomy; of these, the majority had renal lithiasis, carcinoma of the kidney or a congenital anomaly. Emmett and associates 3 studied 183 cases having atrophic kidneys but without an obvious etiological agent. Seventynine of these underwent nephrectomy, 51 of which were diagnosed as chronic atrophic pyelonephritis. The remainder were diagnosed a5 aplasia, hypoplasia and hypoplasia with chronic atrophic pyelonephritis. During the 5 year period of 1953-1957 inclusive, 255 nephrectomies were performed at Barnes Hospital. Of these, 83 (32.5 per cent) were urographically nonvisualizing kidneys. This number is not all inclusive as 17 other patients had nephrectomies ·without preceding "function" studies being performed; these are not included among the 83. Twelve of tbe 83 patients had a retrograde urogram without preceding intravenous urogram, but function studies were clone by employing indigo carmine dye administered intravenously. Kidneys failing to show function are included in the group of non visualizing kidneys. Fourteen cases with poor or longdelayed visualization of the removed kidney are not included. For purposes of this study, all available roentgenograms from the 255 cases and all of the histological reports and sections from the 83 nonvisualizing cases were reviewed. A minimum of 3 histologic sections were studied from each kidney. From the histologic material and the gross description of the resected nonvisualizing kidneys a crude estimate of function was made.
Accepted for publication April 11, 1960. * Present address: 607 N. Grand Blvd., St. Louis 3,Mo. 1 Hartman, G.: Die Bedentnng der Angiographie fi.ir Diagnostik und Therapie der sogenannten functionlosen Niere. :vinench. med. Wochnschr.,
2 Strandness, D. E, Jr.: The unilateral nonfunctioning kidney. Arch. Int. Med., 101: 611-619, 3 Emmett, J, L., Alvarez-Ierena, J. J. and McDonald, J. R.: Atrophic pyelonephritis versus congenital renal hypoplasia. J.A.M.A., 148: 1470-
101: 1264-1265, 19,59.
1477, 1952. 115
1958.
116
H. J. SPJUT AND C. H. NICOLAI TABLE
1. Major diagnostic groups
TABLE
2. Histologic diagnoses of nonvisualizing
kidneys
I
Pyelonephritis
Cancer
Other Diseases
'
Non visualizing kidney (83) ... 54 (65%) 7 (8.5%) 22 (26.5%) Visualizing kidney (172). 71 (41%) 62 (36%) 39 (23%) All kidneys (255) . 125 (49%) 69 (27%) 61 (24%)
This was based upon the amount of histologically or grossly normal appearing tissue in relation to diseased renal parenchyma. Except for a history of hypertension, known urinary tract obstruction, or history of trauma to the urinary tract, the historical data, physical examination, and clinical laboratory tests of the patient with a, nonvisualizing kidney gave no information that would categorically separate this patient from one with a visualizing kidney. Among the 83 patients there were 39 males and 44 females. Thirteen of the patients were children under the age of 15 years. The average age of the entire group was 45 years. The average age of the children was 3.3 years with an age range of 3 days to 14 years. The average age of the adults was 52 years with an age span of 17 to 77 years. From the pathological standpoint, pyelonephritis either in its acute or chronic form. was the most common histological lesion among the 255 nephrectomies (125 or 49 per cent). There were 69 (27 per cent) malignant tumors. Pyelonephritis was found in 65 per cent (54 cases) of the nonvisualizing kidneys, but there were only 7 (8.5 per cent) nonvisualizing kidneys with malignant tumors (table 1). The remammg pathologic diagnoses included dysplasia, renal artery aneurysm, infarction, arteriolonephrosclerosis, tuberculosis, trauma, and cysts of various sizes and numbers. The observations on pathologic entities do not pertain to the 13 children, admittedly a small group (table 2). Five of the nephrectomies for a nonvisualizing kidney were done in children for a dysplastic kidney,4 these usually being manifest as an intra-abdominal mass. Four of the 13 children had pyelonephritis. One of the four pyelonephritic kidneys exhibited focal dysplasia. In 4 Ericsson, N. 0. and Ivemark, B. I.: Renal dysplasia and pyelonephritis in infants and children. Arch. Path., 66: 2,55-263, 1958.
Histologic Diagnoses
Adults
Children
--------~~~1~---- -----
Pyelonephritis. Renal cell carcinoma. JVIetastatic carcinoma. Carcinoma of renal pelvis. Wilms tumor . Renal dysplasia. Granulom.atous diseases .. Trauma. Infarction . Arteriolonephrosclerosis ..
50 (71%) 4 4 (6%) 1 (1. 5%) 1 (1.5%) 1 3 (4.5%) 5 1 4 (6%) 1 (1.5%) 1 1 (i (9%)
(30.8%)
(7. 7%) (38.5%) (7. 7%) (7. 7%) (7. 7%)
addition, the kidney slwwing thrombosis of hilar vessels and extensive parenchymal infarction contained focal dysplastic areas. Thus, seven of the children's nephrectomy specimens revealed dysplasia,. In the total group of 255 ncphrectomies there were seven vVilms' tumors, but only one of these was nonvisualizing. Obstruction to the outflow of urine from the kidney prevents excretion of the contrast medium. 5 Venous and arterial obstruction is also an important factor. Of the 83 nonvisualizing kidneys, 62 had evidence of urinary drainage obstruction as shown by pyelocalicctasis or presence of a potentially obstructing lesion, such as a renal stone. Three of those 62 had major venous or arterial occlusion. Not all specimens with renal stones or other potentially obstructing lesions exhibited calyceal and pelvic dilatation. Eleven kidneys showed dilatation of the pelvis or calyces without clinical (or pathological) evidence of an obstructing lesion. Of the 83 nonvisualizing kidneys, 26 contained renal stones or had recently undergone nephrolithotomy; 22 others were associated with obstruction such as carcinoma of the bladder, advanced carcinoma of the uterine cervix, previous pelvic surgery, or inflammatory stenosis of the ureter at the ureteropelvic junction. The 8 kidneys diagnosed as renal dysplasia were not included in the obstructed group. An estimate of the function of an organ or part of an organ from the histological viewpoint cannot always be accurate. Slight deviations in the physiological or biochemical functions may not be reflected as altered histological findings. Thus our estimate of the function of a kidney from 5 Idbohrn, H.: Delayed excretion in urography and its significance. Acta radiol., 42: 1-10, 1954.
117
THE KONVISUALIZING KIDKEY
the histological and gross alterations is at best crude. This part of the study was done because, as had been previously stated, a number of nonvisualizing kidneys appeared to have a considerable amount of functionally intact parenchyma as determined from gross and histological considerations. Using the pathological features there were 5 (6 per cent) adult kidneys estimated to have 75 per cent or more functional parcnchyma. Four of these weighed within the normal range of 105 gm. to 195 gm. One weighed 380 gm. and had marked dilatation of the calyces and pelvis secondary to ureteral stenosis. Four of the 5 kidneys exhibited some degree of pelvic dilatation, although histologieally retaining a great deal of "functional" parenchyma. One kidney without dilatation of the pelvis or c:ilyces had a solitary abscess in the upper pole; the remainder of the kidney appeared normal. Twelve kidneys were estimated to have at least 50 per cent functional parenchyma. Three of the 12 (14.4 per cent) kidneys weighed less than 100 gm. The others were in the normal weight range for a single kidney except for one which contained a renal cell carcinoma. Six of the 12 kidneys displayed dilatation of the calyces and pd vis; six did not. The remaining 66 (79.6 per cent) kidneys had less than 25 per cent "functional" parenchyma. Forty had ealyceal and pelvic dilatation. Seventeen weighed less than 100 gm. The kidneys in this group ranged in weight from 8 gm. to 1550 gm. The latter was a severe chronic pyelonephritis with extensive xanthogranulomatous change. Thus it is evident that very few nonvisualizing kidneys are entirely normal. Even though a substantial amount of "functional" parenchyma may be present, obstruction to urinary outflow is often evident. This probably indicates that obstruction is an important basic factor in the pathogenesis of the nonvisualizing kidney. However, if a kidney is within the range of normal size by roentgen examination, the suggestion might be made that a moderate amount of "functional" parenchyma may be present and a more conservative management might be considered. (See Comments.) Stones were found in 26 of the nonvisualizing kidneys; none of the ncphrectomy specimens from children contained stones. Eleven of the stones were of the staghorn type. Eight stones were in the ureter or impacted in the ureteropelvic junction. Each of the 26 kidneys exhibited
pyelonephritis; one had a renal cell carcinoma and pyelonephritis. Of the 26 kidneys, 20 had less than 25 per cent "functional" parcnchyma, 5 had 50 per cent "functional" parem:hyma and one had 75 per cent. Among the 83 patients with nonvisualizing kidneys, there were 19 who had cxtrarenal conclitions which ultimately led to nephrectomy. The most frequent extrarenal cause for nephrectomy was carcinoma of the uterine cervix. Nine of these 19 patients had undergone therapy for this condition between a few weeks to 11 years earlier. In one patient recurrent carcinoma of the cervix was associated with metastases to the kidney. Another patient had a ureter severed during hysterectomy for carcinoma of the cervix. One had a retroperitoneal abscess complicating a 1Vertheim hysterectomy. The next most common extrarenal lesion contributing to poor kidney function was carcinoma of the urinary bladder. There were four such patients. One patient who had recurrent papillary carcinoma of the bladder underwent cystectomy and ilea! conduit diversion 6 years prior to nephrcctomy. Subsequently, urograms demonstrated a nonvisualizing kidney that proved by retrograde pyelography to contain an infiltrating transitional cell carcinoma of the pe1vis; severe acute and chronic pyelonephritis was noted on histological examination. The other 6 patirnts each had one of the following conditions which contributed to their renal disease: abdominoperineal resection of the sigmoid colon for carcinoma, transurethral and suprapubic prostatectomies (same patient), quadriplegia, pregnancy, traumatic renal laceration, and tuberculosis. Seven patients, other than the 19 just discussed, underwent nephrectomy following an evaluation which pointed to a renal etiology of their hypertension. Two of these had arteriolonephrosderosis, two had renal infarcts prrcccled by trauma to the kidney, one had thrombosis of the renal artery, one had chronic atrophic pyelonephritis and one had acute pyclonephritis. COMMENTS
Our study indicates that obstruction to urinary outflow is the most common (62 of 83 kidneys) basic pathogenic factor of the urographica.lly nonvisualizing kidney. This only serves to confirm the urographic observation that obstruction to
118
H. J. SPJUT AND C. H. NICOLAI
outflow of urine results in delayed or absent excretion of contrast medium. 5 Pyelonephritis in its acute and chronic form is the most common finding in nonvisualizing kidneys (54, or 65 per cent). In addition, pyclonephritis was associated with the dominant disease in 10 other nephrectomy specimens, e.g. in the four renal cell carcinomas and the carcinoma of the renal pelvis. Neoplasms accounted for less than 10 per cent of the nonvisualizing kidneys. A statistical comparison between the groups of visualizing and nonvisualizing kidneys demonstrated a statistical significance to the preponderance of pyelonephritis over neoplastic disease (x 2 = 22.6, P = 0.001). Since our group of children was small, no pertinent statements about the pathological findings could be made. However, only one of the 13 kidneys contained a neoplasm whereas nine of the kidneys were either dysplasia or pyelonephritis. Thus the trend is maintained. No entirely normal kidney was found among the nonvisualizing group. Twenty per cent of the 83 kidneys did have an abundant amount of normal appearing parenchyma. Most of these kidneys had dilatation of the ureter and pelvis indicating some obstruction to account for nonvisualization. Since one-fifth of the kidneys had a significant amount of normal parenchyma remaining, evaluation of the entire urinary tract should be performed prior to nephrectomy so
that renal tissue may be preserved by removing obstruction. Kidneys have a remarkable recuperative capacity following the removal of obstruction to the outflow of urine. 5 • 6 SUMMARY
A pathological and roentgenological review of 83 nonvisualizing kidneys was made in an attempt to define such a kidney. Obstruction to urinary outflow was present in 75 per cent of the kidneys and probably represents the basic factor accounting for nonvisualization. Fifty-four (65 per c.;ent) of the nonvisuarizing kidneys were pyelonephritic. Only 8.5 per cent of the kidneys contained a neoplasm. In children, pyelonephritis and dysplasia were the commonest causes of a nonvisualizing kidney. One-fifth of the nonvisualizing kidneys had an appreciable amount of normal appearing parenchyma. Other diseases among the nonvisualizing kidneys included arteriolonephrosclerosis, injury due to eirternal trauma, infarction, and granulomatous processes.
Surgical Pathology, Barnes IIosp., St. Louis 10, Mo. (H.J. S.) 6 Rolleston, G. L. and Reay, E. R.: The pelviureteric junction. Brit. J. Radio!., 30: 617-625, 1957.