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Unsuspected Renal Tumors Associated with Renal Cysts
Vol. 117, June Printed in U.S.A.
THE JOURNAL OF UROLOGY
Copyright © 1977 by The Williams & Wilkins Co.
UNSUSPECTED RENAL TUMORS ASSOCIATED WITH RENAL CYSTS SAMUELS. AMBROSE,* ERNEST L. LEWIS, DAVID P. O'BRIEN, III, KENNETH N. WALTON AND J. RUSSELL ROSS From the Department of Surgery, Section of Urology, Emory University School of Medicine, Atlanta, Georgia
ABSTRACT
A series of renal tumors associated with renal cysts is presented. Prior to surgical exploration appropriate diagnostic studies failed to indicate evidence of the presence of neoplastic lesions. The importance of surgical exploration of avascular "benign" renal masses is emphasized. The reported high confidence level in distinguishing benign renal cyst from renal neoplasm by the sequential use of nephrotornography, sonography, renal arteriography and cyst puncture is disturbing. 1 Various authors have reported diagnostic confidence or accuracy levels of 87 to 96 per cent but to date they have not reported adequate supporting histological confirmation of their diagnostic accuracy nor have they presented long-term followup adequate to prove their non-histological presumption of benignancy of the non-operated benign cyst. 1--4 There seems to be a clear and increasing danger of overconfident interpretation of our available diagnostic modalities, with the consequent risk to patient and doctor of unwarranted assurance that an avascular renal mass lesion has no related neoplastic process. The possibility of the simultaneous occurrence of a benign renal cyst and a renal neoplasm is reported variously to be from 2.3 to 7 per cent. 5• 6 Reviews of arteriographic findings in malignant renal neoplasms consistently indicate a small percentage ofturnors without abnormal vessels. 7 • 8 Nephrotornography is reported to have a 5 to 10 per cent margin of error in renal mass differentiation. 2 • !H 1 Masses smaller than 3 crn. are not demonstrated reliably by ultrasound. 12- 14 The vascularity of some renal tumors is not sufficient for detection by currently available isotope renal scanning. 15 Lang has reported that cytological examination of fluid aspirated from avascular mass lesions was positive in 5 of 5 aspirates from cyst associated with turnor. 16 Those who advocate acceptance of the results of planned sequential, non-surgical diagnostic procedures as the final answer in differentiating benign renal cyst from renal neoplasms do so with full knowledge of an error rate of 4 to 13 per cent. The most compelling argument to support their position has been that the 4 to 13 per cent chance of missing a renal neoplasm is offset by the mortality rate for surgical exploration of the kidney. 4 • 17 Their conclusion is that the patient would be safer taking his chances with the possible diagnostic error rather than with the possible mortality ofrenal exploration. Lang, in opposing surgical exploration of a presumed renal cyst, supports his position by reporting a confidence level of 96 per cent for a planned sequential diagnostic test and an expected mortality rate for surgical exploration of the kidney of 10 per cent for the 65-year age group and 25 per cent for the SO-year age group. 16 In the same report Lang quotes the work of Plaine and Hinman but overlooks their reported mortality rate of 2.3 per cent in renal exploration for presumed cyst. 18 Gonzalez-Serva and associates report a 1.35 per cent mortality rate in their series of renal explorations. rn Other than providing the most accurate determination of the nature of a renal mass available, histological confirmation, there at times are other compelling reasons for surgical Accepted for publication August 27, 1976. *Requests for reprints: 1365 Clifton Rd., N. E., Atlanta, Georgia 30322.
exploration of presumed renal cyst. The cyst may produce pain and/or parenchyrnal destruction requiring surgical intervention. Obstruction by the cyst of the urinary drainage system, bleeding, hypertension, infection or cyst rupture also may require surgical intervention. We have cuntinued our policy of exploration of avascular renal masses if the patient was a reasonable surgical risk, had a reasonable life expectancy and agreed after explanation of the risk of diagnostic error versus the risk of an operation. We report the results of this policy from January 1970 to January 1976, a period when a full range of radiological diagnostic facilities were available, appreciated and used. At Emory University Hospital 55 patients were explored for a presumed renal cyst. During the same period 38 patients had nephrectorny for renal neoplasm. In the group of presumed renal cyst 5 patients were found by surgical exploration and histological examination to have previously unsuspected and undetected renal neoplasms. Two other patients were explored for presumed renal cyst at Piedmont Hospital during this same period and were found to have unsuspected renal tumors and are included in our 7 case reports. CASE REPORTS
Case 1. A 53-year-old white man, EUH 207-974, had a 3rnonth history of left flank pain. There was no history of gross hernaturia, trauma, urinary tract infection, dysuria or urinary calculi. Physical examination was essentially normal except for moderate obesity, blood pressure 180/100 and left upper quadrant abdominal tenderness. Laboratory studies were within normal range. An excretory urograrn (IVP) revealed a calcific density overlying the lower pole of the left kidney and an apparent mass in the mid portion of the left kidney with compression of the lower pole calices and obstruction of the infundibulurn of the superior main calix. Aortography and selective left renal arteriography revealed an avascular left peripelvic mass without evidence of neovascularity or other changes suggestive of tumor. Exploration of the left kidney revealed a left peripelvic cyst and a previously undetected multiloculated cyst Df the upper pole. Cyst fluid obtained from both lesions was clear, strawcolored and negative for evidence ofturnor cells. Biopsy of both cyst walls revealed a simple, benign peripelvic cyst and a cystic clear cell carcinoma producing the rnultiloculated lesion. A left modified radical nephrectorny was done and the patient was well 8 months postoperatively. Case 2. A 54-year-old white woman, EUH 205-029, had had abdominal pain on the right side for 2 weeks, vomiting, fever and gross hematuria. Physical examination revealed a blood pressure of 150/84, temperature 99.4 and a tender mass in the right upper quadrant. Laboratory studies revealed grossly bloody urine and a serum lactic dehydrogenase of 448 rnu. per rnl. An IVP and retrograde pyelography revealed an enlarged right kidney with caliceal blunting and poor drainage with
704
of the lumbar ""''"'w,,n:h" and selective renal
Case 3. A
man, EUH 190-683, had a 3vague abdominal pain but was otherwise asymptomatic. Physical examination revealed a blood pressure of 160/100 but was otherwise unremarkable. Laboratory studies were within normal range but an IVP revealed a mass in the mid portion of the left kidney. An abdominal aortogram and selective renal arteriogram revealed an avascular left mid renal mass characteristic of a benign renal cyst. Exploration of the left kidney revealed a unilocular cyst and aspiration of the cyst revealed straw-colored clear fluid that was negative for tumor cells. When the cyst was opened in preparation for partial resection it was immediately obvious that there was a renal tumor involving the cyst wall and adjacent parenchyma. A simple left nephrectomy was performed and the pathologic report was clear cell carcinoma within a renal cyst. The patient was well without known metastases 3 years 3 months postoperatively.
vrhite man, EUF.£ 181-213, had a 1rnonth flank pain and a of calculi. findings were iimited to a non-tender left upper abdominal mass. studies were within normal range. IVPs revealed a mass lesion involving the of the left kidney suggestive of a unilocular cyst .•• ,"c.'!,';~'"r.'~.':"l.'.l. aortography and selective renal arteriography revealed an avascular mass involving the upper pole of the left kidney without evidence of neovascularity. Exploration of the left kidney :revealed what grossly appeared to be a benign renal cyst. Aspiration of the cyst revealed clear, strawcolored fluid that was negative for tumor cells. When the cyst was opened for exploration a renal tumor was found involving the cyst wall and adjacent parenchyma. A radical left nephrecOperative experience with renal mass lesions (cystic or neoplastic) during a 6-year period at Emory University Hospital, January 1970 to January 1976 No. Exploration for renal tumor Exploration for presumed benig11 renal cyst Renal tumor found at exploration for cyst Presumed benign cyst with renal tumor Operative mortality rate in 93 consecutive patients explored for renal mass lesion
(%)
38 55 5
9.1 0.0
Case 7. A, plain x-ray reveals large left renal shadow and calcific density in area of lower pole. B, IVP reveals mass lesion in hilar area with compression and obstruction of pelvis and caliceal system. C, retrograde pyelogram confirms intrahilar obstruction of drainage system. D, selective arteriogram of superior 2 left renal arteries reveals compression oflower branch and no neovascularity. E, selective arteriogram of inferior 2 left renal arteries reveals medial compression and no neovascularity in area of mass.
706
AMBROSE AND ASSOCIATES
tomy was done and the patient was well without known metastases 4 years 10 months postoperatively. Case 5. A 64-year-old white man, EUH 072-958, had gross, total, painless hematuria. Positive findings on physical examination were blood pressure 140/100, temperature 100.2F and right upper quadrant tenderness. Laboratory studies were within normal limits except for grossly bloody urine. IVPs revealed a mass involving the mid portion of the right kidney, and abdominal aortography and selective renal arteriography revealed an avascular right renal mass compatible with a cyst but no evidence ofneovascularity. Percutaneous cyst puncture was performed, clear straw-colored fluid was negative for tumor cells, and a chemical assay revealed low fat content and normal protein and lactic dehydrogenase content. Cystography was negative for any evidence of tumor. Subsequent exploration of the right kidney revealed multiple right renal cysts involving the mid portion of the kidney and an adjacent solid tumor involving the upper pole of the right kidney that had been undetected previously. A right nephrectomy was done and the pathological report revealed multiple simple renal cysts with clear cell carcinoma involving the upper pole of the kidney. The patient was well without evident metastases 9 months postoperatively. Case 6. A 50-year-old white man, PH 390-728, was referred because of a left renal mass found during evaluation for hypertensive vascular disease. He had been asymptomatic previously. Physical examination was within normal limits except for blood pressure of 142/104. Laboratory studies were within normal limits except for uric acid of 11.6 mg. per cent. IVPs revealed a mass involving the upper pole of the left kidney consistent with unilocular cyst. Nephrotomograms confirmed the presence of the mass and again were consistent with unilocular cyst. Abdominal aortography and selective renal arteriography revealed an avascular renal mass involving the superior pole of the left kidney consistent with benign cyst. Subsequent exploration of the left kidney revealed a unilocular cyst lesion over the upper pole of the kidney and aspiration revealed cloudy fluid that subsequently was proved to be negative for tumor cells. When the cyst was opened for exploration 2 (2 to 3 cm.) plaque-like lesions were noted on the cyst wall, involving the adjacent parenchyma. A left nephrectomy was done and the pathological report was renal cyst with 2 foci of clear cell carcinoma involving the cyst wall. The patient died 4 years postoperatively of myocardial infarction without known recurrence of the neoplastic disease. Case 7. A 67-year-old white man, PH 395-729, had symptoms of prostatism and hypertensive vascular disease. Physical examination revealed a blood pressure of 150/100 and benign prostatic hypertrophy. Laboratory studies were within normal limits except for pyuria. An IVP revealed lateral displacement of the upper calix of the left kidney by a mass arising in the medial aspect of the upper pole of the kidney. Nephrotomography revealed a 6.5 cm. mass in the upper portion of the left kidney, which was believed to be consistent with unilocular renal cyst. Abdominal aortography and renal arteriography revealed an avascular mass in the superior and medial aspect of the left kidney without evidence of neovascularity, and was interpreted as consistent with benign cyst. Exploration of the left kidney revealed a unilocular cyst involving the medial aspect of the upper pole of the left kidney and aspiration of the cyst revealed clear, straw-colored fluid that contained no evident tumor cells. Exploration of the cyst revealed a tumor involving the lining of the cyst and the adjacent parenchyma. The tumor was approximately 2.5 cm. in diameter. A partial nephrectomy included the cyst and tumor. The pathological report was clear cell carcinoma in a renal cyst. The patient was well without evident metastases 4½ years postoperatively (see figure).
mass lesions (see table). Of our 55 patients 9.1 per cent with avascular renal masses were found to have previously undetected renal neoplasms. Review of the gross pathological material indicates that sonography may have aided in the detection of the neoplasm in 2 cases. 12 Cyst fluid was obtained in 4 of our cases and was cytologically negative for tumor cells in each. Cyst puncture and renal cystography in 1 patient failed to detect the neoplasm. One of the 7 patients with unsuspected renal neoplasm died 4 years postoperatively without known metastatic disease. Six of the patients are living for 8 to 58 months without known metastatic disease. Until the high confidence level in planned sequential studies ofrenal masses is supported by histological confirmation of the diagnostic accuracy of these sequential studies, we are obligated to offer the patient with an avascular renal mass the opportunity for precise histological definition of the nature of the mass if the patient is not at significant increased surgical risk. REFERENCES
1. Pollack, H. M., Goldberg, B. B., Morales, J. 0. and Bogash, M.: A systematized approach to the differential diagnosis of renal masses. Radiology, 113: 653, 1974. 2. Lang, E. K., Johnson, B., Chance, H. L., Enright, J. R., Fontenot, R., Trichel, B. E., Wood, M., Brown, R. and St. Martin, E. C.: Assessment of avascular renal mass lesions: the use of nephrotomography, arteriography, cyst puncture, double contrast study and histochemical and histopathologic examination of the aspirate. South. Med. J., 65: 1, 1972. 3. Raskin, M. M., Poole, D. 0., Roen, S. A. and Viamonte, M., Jr.: Percutaneous management of renal cysts: results of a fouryear study. Radiology, 115: 551, 1975. 4. Viamonte, M., Jr., Roen, S., Raskin, M. M., LePage, J., Russell, E. and Viamonte, M.: Why every renal mass is not always a surgical lesion. The need for an orderly, logical, diagnostic approach. J. Urol., 114: 190, 1975. 5. Levine, S. R., Emmett, J. L. and Woolner, L.B.: Cyst and tumor occurring in the same kidney. J. Urol., 91: 8, 1964. 6. Rehm, R. A., Taylor, W. N. and Taylor, J. N.: Renal cyst associated with carcinoma. J. Urol., 86: 307, 1961. 7. Leitner, W. A., Anderson, E. E., Weber, C. H., Grimes, J. H. and Johnsrude, I. S.: Limitations of arteriography in renal mass evaluation. Arch. Intern. Med., 130: 868, 1972. 8. Meaney, T. F.: Errors in angiographic diagnosis of renal masses. Radiology, 93: 361, 1969. 9. Chynn, K. Y. and Evans, J. A.: Nephrotomography in the differentiation of renal cyst from neoplasm: a review of 500 cases. J. Urol., 83: 21, 1960. 10. Kaiser, T. F., Hodson, J.M., Seibel, R. E., Albee, R. D., Farrow, F. C. and McMahon, J. J.: Evaluation of asymptomatic renal masses by selective renal angiography and percutaneous needle puncture: a preliminary report. J. Urol., 98: 436, 1967. 11. Pfister, R. C. and Shea, T. E.: Nephrotomography. Performance and interpretation. Radiol. Clin. N. Amer., 9: 41, 1971. 12. Bloom, J. N., Mattey, W. E., Arevalo, F. L. and DelGuercio, L. R. M.: B-mode ultrasound scanning in the diagnosis of renal lesions. Amer. J. Surg., 129: 636, 1975. 13. Pollack, H. M. and Goldberg, B. B.: Differentiating renal masses with ultrasound. In: Urology-73. New York: McGraw-Hill Book Co., pp. 31-32, 1973. 14. Smith, E. H. and Bennett, A.H.: The usefulness of ultrasound in the evaluation of renal masses in adults. J. Urol., 113: 525, 1975. 15. Morales, J. 0.: Space-occupying lesions of the kidney. Semin. Nucl. Med., 4: 133, 1974. 16. Lang, E. K.: Roentgenographic assessment of asymptomatic renal lesions. Radiology, 109: 157, 1973. 17. Kropp, K. A., Grayhack, J. T., Wendel, R. M. and Dahl, D.S.: Morbidity and mortality of renal exploration for cyst. Surg., Gynec. & Obst., 125: 803, 1967. 18. Plaine, L. I. and Hinman, F., Jr.: Malignancy in asymptomatic renal masses. J. Urol., 94: 342, 1965. 19. Gonzalez-Serva, L., Weinerth, J. L. and Glenn, J. F.: The minimal mortality of renal surgery. Personal communications.
DISCUSSION
COMMENT
There were no operative or postoperative deaths in this series of 93 patients undergoing surgical exploration for renal
The authors present a significant counterpoint to the trend toward maximizing non-surgical techniques in establishing the benignity of
THE JOURNAL OF UROLOGY
Copyright © 1977 by The Williams & Wilkins Co.
UNSUSPECTED RENAL TUMORS ASSOCIATED WITH RENAL CYSTS SAMUELS. AMBROSE,* ERNEST L. LEWIS, DAVID P. O'BRIEN, III, KENNETH N. WALTON AND J. RUSSELL ROSS From the Department of Surgery, Section of Urology, Emory University School of Medicine, Atlanta, Georgia
ABSTRACT
A series of renal tumors associated with renal cysts is presented. Prior to surgical exploration appropriate diagnostic studies failed to indicate evidence of the presence of neoplastic lesions. The importance of surgical exploration of avascular "benign" renal masses is emphasized. The reported high confidence level in distinguishing benign renal cyst from renal neoplasm by the sequential use of nephrotornography, sonography, renal arteriography and cyst puncture is disturbing. 1 Various authors have reported diagnostic confidence or accuracy levels of 87 to 96 per cent but to date they have not reported adequate supporting histological confirmation of their diagnostic accuracy nor have they presented long-term followup adequate to prove their non-histological presumption of benignancy of the non-operated benign cyst. 1--4 There seems to be a clear and increasing danger of overconfident interpretation of our available diagnostic modalities, with the consequent risk to patient and doctor of unwarranted assurance that an avascular renal mass lesion has no related neoplastic process. The possibility of the simultaneous occurrence of a benign renal cyst and a renal neoplasm is reported variously to be from 2.3 to 7 per cent. 5• 6 Reviews of arteriographic findings in malignant renal neoplasms consistently indicate a small percentage ofturnors without abnormal vessels. 7 • 8 Nephrotornography is reported to have a 5 to 10 per cent margin of error in renal mass differentiation. 2 • !H 1 Masses smaller than 3 crn. are not demonstrated reliably by ultrasound. 12- 14 The vascularity of some renal tumors is not sufficient for detection by currently available isotope renal scanning. 15 Lang has reported that cytological examination of fluid aspirated from avascular mass lesions was positive in 5 of 5 aspirates from cyst associated with turnor. 16 Those who advocate acceptance of the results of planned sequential, non-surgical diagnostic procedures as the final answer in differentiating benign renal cyst from renal neoplasms do so with full knowledge of an error rate of 4 to 13 per cent. The most compelling argument to support their position has been that the 4 to 13 per cent chance of missing a renal neoplasm is offset by the mortality rate for surgical exploration of the kidney. 4 • 17 Their conclusion is that the patient would be safer taking his chances with the possible diagnostic error rather than with the possible mortality ofrenal exploration. Lang, in opposing surgical exploration of a presumed renal cyst, supports his position by reporting a confidence level of 96 per cent for a planned sequential diagnostic test and an expected mortality rate for surgical exploration of the kidney of 10 per cent for the 65-year age group and 25 per cent for the SO-year age group. 16 In the same report Lang quotes the work of Plaine and Hinman but overlooks their reported mortality rate of 2.3 per cent in renal exploration for presumed cyst. 18 Gonzalez-Serva and associates report a 1.35 per cent mortality rate in their series of renal explorations. rn Other than providing the most accurate determination of the nature of a renal mass available, histological confirmation, there at times are other compelling reasons for surgical Accepted for publication August 27, 1976. *Requests for reprints: 1365 Clifton Rd., N. E., Atlanta, Georgia 30322.
exploration of presumed renal cyst. The cyst may produce pain and/or parenchyrnal destruction requiring surgical intervention. Obstruction by the cyst of the urinary drainage system, bleeding, hypertension, infection or cyst rupture also may require surgical intervention. We have cuntinued our policy of exploration of avascular renal masses if the patient was a reasonable surgical risk, had a reasonable life expectancy and agreed after explanation of the risk of diagnostic error versus the risk of an operation. We report the results of this policy from January 1970 to January 1976, a period when a full range of radiological diagnostic facilities were available, appreciated and used. At Emory University Hospital 55 patients were explored for a presumed renal cyst. During the same period 38 patients had nephrectorny for renal neoplasm. In the group of presumed renal cyst 5 patients were found by surgical exploration and histological examination to have previously unsuspected and undetected renal neoplasms. Two other patients were explored for presumed renal cyst at Piedmont Hospital during this same period and were found to have unsuspected renal tumors and are included in our 7 case reports. CASE REPORTS
Case 1. A 53-year-old white man, EUH 207-974, had a 3rnonth history of left flank pain. There was no history of gross hernaturia, trauma, urinary tract infection, dysuria or urinary calculi. Physical examination was essentially normal except for moderate obesity, blood pressure 180/100 and left upper quadrant abdominal tenderness. Laboratory studies were within normal range. An excretory urograrn (IVP) revealed a calcific density overlying the lower pole of the left kidney and an apparent mass in the mid portion of the left kidney with compression of the lower pole calices and obstruction of the infundibulurn of the superior main calix. Aortography and selective left renal arteriography revealed an avascular left peripelvic mass without evidence of neovascularity or other changes suggestive of tumor. Exploration of the left kidney revealed a left peripelvic cyst and a previously undetected multiloculated cyst Df the upper pole. Cyst fluid obtained from both lesions was clear, strawcolored and negative for evidence ofturnor cells. Biopsy of both cyst walls revealed a simple, benign peripelvic cyst and a cystic clear cell carcinoma producing the rnultiloculated lesion. A left modified radical nephrectorny was done and the patient was well 8 months postoperatively. Case 2. A 54-year-old white woman, EUH 205-029, had had abdominal pain on the right side for 2 weeks, vomiting, fever and gross hematuria. Physical examination revealed a blood pressure of 150/84, temperature 99.4 and a tender mass in the right upper quadrant. Laboratory studies revealed grossly bloody urine and a serum lactic dehydrogenase of 448 rnu. per rnl. An IVP and retrograde pyelography revealed an enlarged right kidney with caliceal blunting and poor drainage with
704
of the lumbar ""''"'w,,n:h" and selective renal
Case 3. A
man, EUH 190-683, had a 3vague abdominal pain but was otherwise asymptomatic. Physical examination revealed a blood pressure of 160/100 but was otherwise unremarkable. Laboratory studies were within normal range but an IVP revealed a mass in the mid portion of the left kidney. An abdominal aortogram and selective renal arteriogram revealed an avascular left mid renal mass characteristic of a benign renal cyst. Exploration of the left kidney revealed a unilocular cyst and aspiration of the cyst revealed straw-colored clear fluid that was negative for tumor cells. When the cyst was opened in preparation for partial resection it was immediately obvious that there was a renal tumor involving the cyst wall and adjacent parenchyma. A simple left nephrectomy was performed and the pathologic report was clear cell carcinoma within a renal cyst. The patient was well without known metastases 3 years 3 months postoperatively.
vrhite man, EUF.£ 181-213, had a 1rnonth flank pain and a of calculi. findings were iimited to a non-tender left upper abdominal mass. studies were within normal range. IVPs revealed a mass lesion involving the of the left kidney suggestive of a unilocular cyst .•• ,"c.'!,';~'"r.'~.':"l.'.l. aortography and selective renal arteriography revealed an avascular mass involving the upper pole of the left kidney without evidence of neovascularity. Exploration of the left kidney :revealed what grossly appeared to be a benign renal cyst. Aspiration of the cyst revealed clear, strawcolored fluid that was negative for tumor cells. When the cyst was opened for exploration a renal tumor was found involving the cyst wall and adjacent parenchyma. A radical left nephrecOperative experience with renal mass lesions (cystic or neoplastic) during a 6-year period at Emory University Hospital, January 1970 to January 1976 No. Exploration for renal tumor Exploration for presumed benig11 renal cyst Renal tumor found at exploration for cyst Presumed benign cyst with renal tumor Operative mortality rate in 93 consecutive patients explored for renal mass lesion
(%)
38 55 5
9.1 0.0
Case 7. A, plain x-ray reveals large left renal shadow and calcific density in area of lower pole. B, IVP reveals mass lesion in hilar area with compression and obstruction of pelvis and caliceal system. C, retrograde pyelogram confirms intrahilar obstruction of drainage system. D, selective arteriogram of superior 2 left renal arteries reveals compression oflower branch and no neovascularity. E, selective arteriogram of inferior 2 left renal arteries reveals medial compression and no neovascularity in area of mass.
706
AMBROSE AND ASSOCIATES
tomy was done and the patient was well without known metastases 4 years 10 months postoperatively. Case 5. A 64-year-old white man, EUH 072-958, had gross, total, painless hematuria. Positive findings on physical examination were blood pressure 140/100, temperature 100.2F and right upper quadrant tenderness. Laboratory studies were within normal limits except for grossly bloody urine. IVPs revealed a mass involving the mid portion of the right kidney, and abdominal aortography and selective renal arteriography revealed an avascular right renal mass compatible with a cyst but no evidence ofneovascularity. Percutaneous cyst puncture was performed, clear straw-colored fluid was negative for tumor cells, and a chemical assay revealed low fat content and normal protein and lactic dehydrogenase content. Cystography was negative for any evidence of tumor. Subsequent exploration of the right kidney revealed multiple right renal cysts involving the mid portion of the kidney and an adjacent solid tumor involving the upper pole of the right kidney that had been undetected previously. A right nephrectomy was done and the pathological report revealed multiple simple renal cysts with clear cell carcinoma involving the upper pole of the kidney. The patient was well without evident metastases 9 months postoperatively. Case 6. A 50-year-old white man, PH 390-728, was referred because of a left renal mass found during evaluation for hypertensive vascular disease. He had been asymptomatic previously. Physical examination was within normal limits except for blood pressure of 142/104. Laboratory studies were within normal limits except for uric acid of 11.6 mg. per cent. IVPs revealed a mass involving the upper pole of the left kidney consistent with unilocular cyst. Nephrotomograms confirmed the presence of the mass and again were consistent with unilocular cyst. Abdominal aortography and selective renal arteriography revealed an avascular renal mass involving the superior pole of the left kidney consistent with benign cyst. Subsequent exploration of the left kidney revealed a unilocular cyst lesion over the upper pole of the kidney and aspiration revealed cloudy fluid that subsequently was proved to be negative for tumor cells. When the cyst was opened for exploration 2 (2 to 3 cm.) plaque-like lesions were noted on the cyst wall, involving the adjacent parenchyma. A left nephrectomy was done and the pathological report was renal cyst with 2 foci of clear cell carcinoma involving the cyst wall. The patient died 4 years postoperatively of myocardial infarction without known recurrence of the neoplastic disease. Case 7. A 67-year-old white man, PH 395-729, had symptoms of prostatism and hypertensive vascular disease. Physical examination revealed a blood pressure of 150/100 and benign prostatic hypertrophy. Laboratory studies were within normal limits except for pyuria. An IVP revealed lateral displacement of the upper calix of the left kidney by a mass arising in the medial aspect of the upper pole of the kidney. Nephrotomography revealed a 6.5 cm. mass in the upper portion of the left kidney, which was believed to be consistent with unilocular renal cyst. Abdominal aortography and renal arteriography revealed an avascular mass in the superior and medial aspect of the left kidney without evidence of neovascularity, and was interpreted as consistent with benign cyst. Exploration of the left kidney revealed a unilocular cyst involving the medial aspect of the upper pole of the left kidney and aspiration of the cyst revealed clear, straw-colored fluid that contained no evident tumor cells. Exploration of the cyst revealed a tumor involving the lining of the cyst and the adjacent parenchyma. The tumor was approximately 2.5 cm. in diameter. A partial nephrectomy included the cyst and tumor. The pathological report was clear cell carcinoma in a renal cyst. The patient was well without evident metastases 4½ years postoperatively (see figure).
mass lesions (see table). Of our 55 patients 9.1 per cent with avascular renal masses were found to have previously undetected renal neoplasms. Review of the gross pathological material indicates that sonography may have aided in the detection of the neoplasm in 2 cases. 12 Cyst fluid was obtained in 4 of our cases and was cytologically negative for tumor cells in each. Cyst puncture and renal cystography in 1 patient failed to detect the neoplasm. One of the 7 patients with unsuspected renal neoplasm died 4 years postoperatively without known metastatic disease. Six of the patients are living for 8 to 58 months without known metastatic disease. Until the high confidence level in planned sequential studies ofrenal masses is supported by histological confirmation of the diagnostic accuracy of these sequential studies, we are obligated to offer the patient with an avascular renal mass the opportunity for precise histological definition of the nature of the mass if the patient is not at significant increased surgical risk. REFERENCES
1. Pollack, H. M., Goldberg, B. B., Morales, J. 0. and Bogash, M.: A systematized approach to the differential diagnosis of renal masses. Radiology, 113: 653, 1974. 2. Lang, E. K., Johnson, B., Chance, H. L., Enright, J. R., Fontenot, R., Trichel, B. E., Wood, M., Brown, R. and St. Martin, E. C.: Assessment of avascular renal mass lesions: the use of nephrotomography, arteriography, cyst puncture, double contrast study and histochemical and histopathologic examination of the aspirate. South. Med. J., 65: 1, 1972. 3. Raskin, M. M., Poole, D. 0., Roen, S. A. and Viamonte, M., Jr.: Percutaneous management of renal cysts: results of a fouryear study. Radiology, 115: 551, 1975. 4. Viamonte, M., Jr., Roen, S., Raskin, M. M., LePage, J., Russell, E. and Viamonte, M.: Why every renal mass is not always a surgical lesion. The need for an orderly, logical, diagnostic approach. J. Urol., 114: 190, 1975. 5. Levine, S. R., Emmett, J. L. and Woolner, L.B.: Cyst and tumor occurring in the same kidney. J. Urol., 91: 8, 1964. 6. Rehm, R. A., Taylor, W. N. and Taylor, J. N.: Renal cyst associated with carcinoma. J. Urol., 86: 307, 1961. 7. Leitner, W. A., Anderson, E. E., Weber, C. H., Grimes, J. H. and Johnsrude, I. S.: Limitations of arteriography in renal mass evaluation. Arch. Intern. Med., 130: 868, 1972. 8. Meaney, T. F.: Errors in angiographic diagnosis of renal masses. Radiology, 93: 361, 1969. 9. Chynn, K. Y. and Evans, J. A.: Nephrotomography in the differentiation of renal cyst from neoplasm: a review of 500 cases. J. Urol., 83: 21, 1960. 10. Kaiser, T. F., Hodson, J.M., Seibel, R. E., Albee, R. D., Farrow, F. C. and McMahon, J. J.: Evaluation of asymptomatic renal masses by selective renal angiography and percutaneous needle puncture: a preliminary report. J. Urol., 98: 436, 1967. 11. Pfister, R. C. and Shea, T. E.: Nephrotomography. Performance and interpretation. Radiol. Clin. N. Amer., 9: 41, 1971. 12. Bloom, J. N., Mattey, W. E., Arevalo, F. L. and DelGuercio, L. R. M.: B-mode ultrasound scanning in the diagnosis of renal lesions. Amer. J. Surg., 129: 636, 1975. 13. Pollack, H. M. and Goldberg, B. B.: Differentiating renal masses with ultrasound. In: Urology-73. New York: McGraw-Hill Book Co., pp. 31-32, 1973. 14. Smith, E. H. and Bennett, A.H.: The usefulness of ultrasound in the evaluation of renal masses in adults. J. Urol., 113: 525, 1975. 15. Morales, J. 0.: Space-occupying lesions of the kidney. Semin. Nucl. Med., 4: 133, 1974. 16. Lang, E. K.: Roentgenographic assessment of asymptomatic renal lesions. Radiology, 109: 157, 1973. 17. Kropp, K. A., Grayhack, J. T., Wendel, R. M. and Dahl, D.S.: Morbidity and mortality of renal exploration for cyst. Surg., Gynec. & Obst., 125: 803, 1967. 18. Plaine, L. I. and Hinman, F., Jr.: Malignancy in asymptomatic renal masses. J. Urol., 94: 342, 1965. 19. Gonzalez-Serva, L., Weinerth, J. L. and Glenn, J. F.: The minimal mortality of renal surgery. Personal communications.
DISCUSSION
COMMENT
There were no operative or postoperative deaths in this series of 93 patients undergoing surgical exploration for renal
The authors present a significant counterpoint to the trend toward maximizing non-surgical techniques in establishing the benignity of