COEXISTING
AVASCULAR
LESIONS
AND
RENAL CELL CARCINOMA* MAJ.
G. GRANT
GEHRING,
(MC) USAF
From the Urology Service, Department Wilford Hall USAF Medical Center, Lackland Air Force Base, Texas
ABSTRACT
of Surgery,
An analysis of 99 cases of coexisting renal avascular lesions and renal cell carcinoma (1) a direct pathogenetic relationship exists in the majority; (2) the cyst-related carcinoma at an earlier age; (3) angiography alone is not reliable fm the diagnosis of an apparently mass, and (4) individuals with polycystic kidneys share at least an equal risk of renal the general population.
-
suggests that: tends to occur benign renal carcinoma as
FIGURE 1. Case 1. (A) Zntruvenous pyelogram showing peripherally (eggshell) calci$ed lesion right lower pole; (B) Transcutaneous contrast cystogram of irregular cyst cavity and septation (multilocularity). (C) Selective angiogram revealing no neovascularity. Avascular and cystic lesions associated with renal cell carcinoma are not rare. Sporadic case reports have appeared in the literature, which scarcely serve to emphasize the association of cyst and malignancy that Walsh, in 1951, l reported to be 7 *The views expressed herein are those of the author and do not necessarily reflect the views of the United States Air Force.
UROLOGY
/ AUGUST 1976 / VOLUME
VIII,
NUMBER 2
per cent. Other authors have found that between 2.3 and 2.9 per cent of cysts were associated with malignancy, as proved by surgical exploration. 2*3 Another 5 per cent of renal cell carcinomas have been estimated to appear as angiographically avascular lesions. 4 A series of 99 cases of coexisting avascular mass lesions and renal cell carinoma are reviewed and provide the basis for this report.
183
Case Reports Two case reports of individuals with apparent cystic lesions which ultimately proved to be coexisting renal cell carcinoma are presented. An examination of 1,385 cases of renal cell carcinoma registered with the Armed Forces Institute of Pathology has revealed 97 instances of coexisting carcinoma and avascular mass lesions. Case 1 Nephrectomy specimen showing cyst base after removal of peripheral portion of inflammatory cyst; subsequently nephrectomy performed fn- renal carcinoma (seen above cyst base on bivalved specimen). FIGURE
184
2.
Case
1.
This sixty-year-old Caucasian male was diagnosed in August, 1969, as having clinical Stage C adenocarcinoma of the prostate at which time findings on excretory urography were normal. He was treated with 6,006 rads cobalt-69 Followup urogram in October, 1973, revealed a periph-
UROLOGY
/ AUGUST 1976 ! VOLUME VIII, NUMBER 2
erally calcified right lower pole mass 8 cm. in diameter (Fig. 1A). Selective angiography of the right lower pole renal artery revealed an avascular mass (Fig. 1C). Percutaneous cyst puncture contrast cystography revealed an irregular, cystic lesion (Fig. 1B); cystic fluid was turbid but not bloody and cytologic examination gave negative findings. Exploratory surgery revealed an inflammatory cyst adjacent to renal clear cell carcinoma (Fig. 2). Case 2
This forty-seven-year-old black male was hospitalized for evaluation of acute pain in right flank and right upper quadrant of the abdomen. Hematuria was not present. Hypertension over a two-year period had required increasing antihypertensive therapy. Selective renal vein renins demonstrated abnormally increased renin production from the right kidney. Nephrotomography revealed a 22-cm. cystic mass in the upper pole of the right kidney (Fig. 3A). Arteriography, B-mode sonography, and transcutaneous cystography demonstrated a large, apparently benign cystic lesion (Fig. 3B, C, D). Although results of cytologic examination of the aspirated fluid were negative, the cyst contained old blood. Surgical exploration revealed a massive cystic lesion containing 2,600 cc. of chocolateappearing fluid and was lined with shaggy, necrotic tissue which proved to be renal papillary cystadenocarcinoma (Fig. 4). This patient has remained normotensive since right nephrectomy. The Armed Forces Institute of Pathology Registry shows that 97 proved renal cell carcinomas were associated with avascular cystic lesions. These cystic lesions were subdivided as follows: I. II. III. IV. V.
Multilocular Tumor arising within cyst Cystic tumor Cyst(s) and tumor Polycystic and tumor
7 11
9 62 8
No definite conclusions could be made pathologically in determining which preceded the other, cyst or tumor. Tumor arising in cyst wall, cystic degeneration of tumor, and multilocular cystic degeneration of tumor may collectively demonstrate various patterns of the same pathologic process. Analysis of subgroup IV, consisting of renal cell carcinoma associated with single or simple cysts, reveals that 89 per cent (55 of 62) showed close proximity of cyst and tumor, 8 per cent (5 of 62) same kidney but unrelated, and 3
UROLOGY
/ AUGUST1976
/ VOLUMEVIII, NUMBER2
FIGURE 4. Case 2. Gross nephrectomy specimen demonstrating shaggy lining circumferentially involving large cystic cavity (microscopic diagnosis: papilla y cystadkznocarcinoma).
per cent (2 of 62) opposite kidney. There is a younger age distribution of patients with coexisting cyst and tumor than is generally associated with renal carcinoma (Fig. 5).5 Of 1,385 cases of renal cell carcinoma, 8 were found to have coexisting polycystic renal disease (Table I). Comment Avascular renal cell carcinoma and cysts associated with clinically inapparent renal cell carcinoma are the usual justifications for surgical exploration of avascular renal mass lesions. This philosophy, however, ignores the proved TABLE I. Polycystic kidneys coexisting with
renal cell carcinoma
Case No.
Age
1
27 35 36 37 40 58 70
2 3 4 5 6 7 8
Unknown
Sex Female Female Female
Male Male Female Male Unknown
185
14 12 10 a 6 4 2 0 FIGURE 5. Graph existing cystltumor patients).
showing age incidence of co(ages known for only 59 of
accuracy of nonsurgical diagnosis when all appropriate diagnostic modalities are judiciously applied. 6-1o Surgical exploration alone offers inherent errors of diagnosis and compromised treatment in those proved to have malignancy.ll Also, for most patients the accuracy rate in nonsurgical diagnosis of avascular lesions is close to 100 per cent,g’10 placing surgical exploration in the realm of unacceptable operative mortality. l2 Of the 99 cases of coexisting avascular masses and renal cell carcinoma reported here, 12 strictly avascular lesions were diagnosed by angiography. No case of malignancy has yet been reported in which arteriography, tomography, sonography, and cyst puncture all have unequivocally indicated a benign cystic lesion. It should be emphasized, however, that the evaluation of a renal mass lesion still should be directed by the urologist, since the ultimate decision on surgical exploration can be made best by integrative clinical correlation. For the nonsurgical diagnosis of benign mass lesions to be within acceptable confidence limits, several points warrant special consideration: (1) It appears that not every patient requires arteriography; when nephrotomography provides absolute criteria for a simple cyst, a confirmatory transcutaneous cyst puncture for contrast cystography and cyst fluid analysis provides the definitive diagnosis in the majority of cases. (2) Although operative spillage of tumor cells is considered detrimental to the patient’s survival, von Schreeb et al. l3 have reported no ill effects on the five-year survival rate following needle puncture of renal malignancies; thus it would appear that with the judicious use of cyst puncture to only sonographically homogenous lesions, needle puncture should be less hazardous than open ex-
186
ploration of cyst-related tumors. (3) Although benign hemorrhagic cysts occur, approximately one third of cystic lesions with hemorrhagic fluid are associated with malignancy, l4 suggesting that surgical confirmation is required for all lesions containing hemorrhagic fluid regardless of the other findings. (4) Complex (multilocular) cysts cannot be adequately evaluated without surgical exploration. (5) Large cysts (greater than 18 cm.) are uncommon, difficult to study adequately by contrast cystography, often symptomatic, and probably associated with a high incidence of cystrelated malignancy (Case 2).15 (6) The Mayo Clinic report emphasized the high association of calcified renal masses and malignancy;16 18 of the 99 cases reported herein demonstrated calcification, suggesting that calcification within a renal mass might also warrant operative diagnostic confirmation regardless of the other findings. The suggested criteria for accurate nonsurgical diagnosis of benign avascular or cystic lesions are summarized as follows: 1. Strictly benign,
2. 3. 4. 5.
avascular cystic lesion, by nephrotomography and/or selective renal arteriography. Absence of any calcification. Normal ultrasound (B-mode sonography) study. Smooth-walled unilocular simple cyst of less than 18 cm., by contrast cystography. Clear aspirated cystic fluid with negative findings on cytologic examination.
Only when all these criteria are met, can we be secure in the nonsurgical diagnosis of a benign renal lesion. If these criteria cannot be met unequivocally, surgical exploration is mandatory. Complacency may result in overlooking malignancy in the patient with known polycystic renal diseases - 8 cases reported here bring the total reported in the literature to about 40.‘7-‘g Five of 7 cases of polycystic related renal cell carcinomas in this series occurred in patients under age forty-one. Only on several occasions has malignancy been suspected antemortem or prior to surgery among the reported cases. Whether or not polycystic disease per se predisposes to malignancy remains an unanswered question. Gibson15 defined the possible relationships that exist between solitary cysts of the kidney and malignant tumors: (1) unrelated origin; (2) origin of cyst within a tumor; (3) origin of tumor within a cyst; and (4) origin of a cyst distal to a tumor. Fifty-five of 62 (89 per cent) cases of coexisting malignancies and simple cysts reported
UROLOGY
I
AUGUST 1976 I
VOLUME
VIII,
NUMBER
2
here have been shown to be anatomically closely related, supporting a cause and effect relationship. Gibson’s hypothesis that malignancy can fulfill Hepler’s two prerequisites to cyst formation, tissue ischemia and collecting system obstruction, could explain the observed relationship. Only 7 of the 99 cases of coexisting avascular lesions and renal cell carcinoma can be said to be coincidental and unrelated.
8.
9. 10.
Lackland AFB, Texas 78236 11. References 1. WALSH, A.: Solitary cyst of the kidney and its relationship to renal &our, Br. J. Ural: 23: 377 (1951). 2. EMMETT, J. L., LEVINE, S. R., and WOOLNER, L. B.: Co-existence of renal cyst and tumour; incidence in 1,667 cases, ibid. 35: 403 (1963). 3. BRANNAN, W., MILLER, W., and CRISLER, M.: Coexistence of renal neoplasms and renal cysts, South. Med. J. 155: 749 (1962). 4. WEISS, R. M., BECKER, J. A., DAVIDSON, A. J., and appearance of renal LYTTON, B. : Angiographic papillary-tubular adenocarcinoma, J. Ural. 102: 661 (1969). 5. BENNINGTON, J. L.: Proceedings: Cancer of the kidney etiology, epidemiology, and pathology, Cancer 32: 1017 (1973). 6. MCLAUGHLIN, A. P., III, TALNER, L. B., LEOPOLD, B. R., and MCCULLOUGH, D. L.: Avascular plsimary renal cell carcinoma: varied pathologic and hngiographic features, J. Urol. 111: 587 (1974). Assessment of avascular mass 7. LANG, E. K., et al.:
UROLOGY
/ AUGUST 1976 /
VOLUME VIII, NUMBER 2
12.
13.
14. 15. 16. 17.
18.
19.
lesions: the use of nephrotomography, arteriography, cyst puncture, double contrast study, and histochemical and histopathologic examination of aspirate, South. Med. J. 65: l(l972). ASHER, W. M., and LEOPOLD, G. R. : A streamlined diagnostic approach to renal mass lesions with renal echogram, J: Urol. 108: 205 (1972). POLLACK, H. M., GOLDBERG, B. B., and BOGASH, T. M.: Changing concepts in the diagnosis and management of renal cysts, ibid. 111: 326 (1974). ROMEISER, R. S., WALLS, W. J., and VALK, W. L.: B-scan ultrasound in the evaluation of renal mass lesions, ibid. 112: 9 (1974). REHN, R. A., TAYLOR, W. N., and TAYLOR, J. N.: Renal cyst associated with carcinoma, ibid. 86: 307 (1961). CASARELLA, W. J., VONMICSKY, L. T., and LALLI, A. F. : Latest advances in diagnostic urologic radiology, Urology 1: 501; 506; 523 (1973). VONSCHREEB, T., ARNER, O., SKOUSTED, G., and WIKSTAD, N.: Renal adenocarcinoma. Is there a risk of spreading tumor cells in diagnostic puncture? Stand. J. Urol. Nephrol. 1: 270 (1967). JACKMAN, R. J., and STEVENS, G. M.: Benign hemorrhagic renal cyst, Radiology 110: 7 (1974). GIBSON, T. E.: Inter-relationship of renal cysts and tumors: report of three cases, J. Urol. 71: 241 (1954). DANIEL, W. W., JR., et al.: Calcified renal masses, Radiology 103: 503 (1972). HOWARD, R. M., and YOUNG, J. D., JR.: Two malignant tumors in a polycystic kidney, J. Ural. 102: 162 (1969). MCFARLAND, W. L., WALLACE, S., and JOHNSON, D. E.: Renal carcinoma and polycystic kidney, ibid. 107: 530 (1972). ROBERTS, P. F.: Bilateral renal carcinoma associated with polycystic kidneys, Br. Med. J. 3: 273 (1973).
187
AVASCULAR
LESIONS
AND
RENAL CELL CARCINOMA* MAJ.
G. GRANT
GEHRING,
(MC) USAF
From the Urology Service, Department Wilford Hall USAF Medical Center, Lackland Air Force Base, Texas
ABSTRACT
of Surgery,
An analysis of 99 cases of coexisting renal avascular lesions and renal cell carcinoma (1) a direct pathogenetic relationship exists in the majority; (2) the cyst-related carcinoma at an earlier age; (3) angiography alone is not reliable fm the diagnosis of an apparently mass, and (4) individuals with polycystic kidneys share at least an equal risk of renal the general population.
-
suggests that: tends to occur benign renal carcinoma as
FIGURE 1. Case 1. (A) Zntruvenous pyelogram showing peripherally (eggshell) calci$ed lesion right lower pole; (B) Transcutaneous contrast cystogram of irregular cyst cavity and septation (multilocularity). (C) Selective angiogram revealing no neovascularity. Avascular and cystic lesions associated with renal cell carcinoma are not rare. Sporadic case reports have appeared in the literature, which scarcely serve to emphasize the association of cyst and malignancy that Walsh, in 1951, l reported to be 7 *The views expressed herein are those of the author and do not necessarily reflect the views of the United States Air Force.
UROLOGY
/ AUGUST 1976 / VOLUME
VIII,
NUMBER 2
per cent. Other authors have found that between 2.3 and 2.9 per cent of cysts were associated with malignancy, as proved by surgical exploration. 2*3 Another 5 per cent of renal cell carcinomas have been estimated to appear as angiographically avascular lesions. 4 A series of 99 cases of coexisting avascular mass lesions and renal cell carinoma are reviewed and provide the basis for this report.
183
Case Reports Two case reports of individuals with apparent cystic lesions which ultimately proved to be coexisting renal cell carcinoma are presented. An examination of 1,385 cases of renal cell carcinoma registered with the Armed Forces Institute of Pathology has revealed 97 instances of coexisting carcinoma and avascular mass lesions. Case 1 Nephrectomy specimen showing cyst base after removal of peripheral portion of inflammatory cyst; subsequently nephrectomy performed fn- renal carcinoma (seen above cyst base on bivalved specimen). FIGURE
184
2.
Case
1.
This sixty-year-old Caucasian male was diagnosed in August, 1969, as having clinical Stage C adenocarcinoma of the prostate at which time findings on excretory urography were normal. He was treated with 6,006 rads cobalt-69 Followup urogram in October, 1973, revealed a periph-
UROLOGY
/ AUGUST 1976 ! VOLUME VIII, NUMBER 2
erally calcified right lower pole mass 8 cm. in diameter (Fig. 1A). Selective angiography of the right lower pole renal artery revealed an avascular mass (Fig. 1C). Percutaneous cyst puncture contrast cystography revealed an irregular, cystic lesion (Fig. 1B); cystic fluid was turbid but not bloody and cytologic examination gave negative findings. Exploratory surgery revealed an inflammatory cyst adjacent to renal clear cell carcinoma (Fig. 2). Case 2
This forty-seven-year-old black male was hospitalized for evaluation of acute pain in right flank and right upper quadrant of the abdomen. Hematuria was not present. Hypertension over a two-year period had required increasing antihypertensive therapy. Selective renal vein renins demonstrated abnormally increased renin production from the right kidney. Nephrotomography revealed a 22-cm. cystic mass in the upper pole of the right kidney (Fig. 3A). Arteriography, B-mode sonography, and transcutaneous cystography demonstrated a large, apparently benign cystic lesion (Fig. 3B, C, D). Although results of cytologic examination of the aspirated fluid were negative, the cyst contained old blood. Surgical exploration revealed a massive cystic lesion containing 2,600 cc. of chocolateappearing fluid and was lined with shaggy, necrotic tissue which proved to be renal papillary cystadenocarcinoma (Fig. 4). This patient has remained normotensive since right nephrectomy. The Armed Forces Institute of Pathology Registry shows that 97 proved renal cell carcinomas were associated with avascular cystic lesions. These cystic lesions were subdivided as follows: I. II. III. IV. V.
Multilocular Tumor arising within cyst Cystic tumor Cyst(s) and tumor Polycystic and tumor
7 11
9 62 8
No definite conclusions could be made pathologically in determining which preceded the other, cyst or tumor. Tumor arising in cyst wall, cystic degeneration of tumor, and multilocular cystic degeneration of tumor may collectively demonstrate various patterns of the same pathologic process. Analysis of subgroup IV, consisting of renal cell carcinoma associated with single or simple cysts, reveals that 89 per cent (55 of 62) showed close proximity of cyst and tumor, 8 per cent (5 of 62) same kidney but unrelated, and 3
UROLOGY
/ AUGUST1976
/ VOLUMEVIII, NUMBER2
FIGURE 4. Case 2. Gross nephrectomy specimen demonstrating shaggy lining circumferentially involving large cystic cavity (microscopic diagnosis: papilla y cystadkznocarcinoma).
per cent (2 of 62) opposite kidney. There is a younger age distribution of patients with coexisting cyst and tumor than is generally associated with renal carcinoma (Fig. 5).5 Of 1,385 cases of renal cell carcinoma, 8 were found to have coexisting polycystic renal disease (Table I). Comment Avascular renal cell carcinoma and cysts associated with clinically inapparent renal cell carcinoma are the usual justifications for surgical exploration of avascular renal mass lesions. This philosophy, however, ignores the proved TABLE I. Polycystic kidneys coexisting with
renal cell carcinoma
Case No.
Age
1
27 35 36 37 40 58 70
2 3 4 5 6 7 8
Unknown
Sex Female Female Female
Male Male Female Male Unknown
185
14 12 10 a 6 4 2 0 FIGURE 5. Graph existing cystltumor patients).
showing age incidence of co(ages known for only 59 of
accuracy of nonsurgical diagnosis when all appropriate diagnostic modalities are judiciously applied. 6-1o Surgical exploration alone offers inherent errors of diagnosis and compromised treatment in those proved to have malignancy.ll Also, for most patients the accuracy rate in nonsurgical diagnosis of avascular lesions is close to 100 per cent,g’10 placing surgical exploration in the realm of unacceptable operative mortality. l2 Of the 99 cases of coexisting avascular masses and renal cell carcinoma reported here, 12 strictly avascular lesions were diagnosed by angiography. No case of malignancy has yet been reported in which arteriography, tomography, sonography, and cyst puncture all have unequivocally indicated a benign cystic lesion. It should be emphasized, however, that the evaluation of a renal mass lesion still should be directed by the urologist, since the ultimate decision on surgical exploration can be made best by integrative clinical correlation. For the nonsurgical diagnosis of benign mass lesions to be within acceptable confidence limits, several points warrant special consideration: (1) It appears that not every patient requires arteriography; when nephrotomography provides absolute criteria for a simple cyst, a confirmatory transcutaneous cyst puncture for contrast cystography and cyst fluid analysis provides the definitive diagnosis in the majority of cases. (2) Although operative spillage of tumor cells is considered detrimental to the patient’s survival, von Schreeb et al. l3 have reported no ill effects on the five-year survival rate following needle puncture of renal malignancies; thus it would appear that with the judicious use of cyst puncture to only sonographically homogenous lesions, needle puncture should be less hazardous than open ex-
186
ploration of cyst-related tumors. (3) Although benign hemorrhagic cysts occur, approximately one third of cystic lesions with hemorrhagic fluid are associated with malignancy, l4 suggesting that surgical confirmation is required for all lesions containing hemorrhagic fluid regardless of the other findings. (4) Complex (multilocular) cysts cannot be adequately evaluated without surgical exploration. (5) Large cysts (greater than 18 cm.) are uncommon, difficult to study adequately by contrast cystography, often symptomatic, and probably associated with a high incidence of cystrelated malignancy (Case 2).15 (6) The Mayo Clinic report emphasized the high association of calcified renal masses and malignancy;16 18 of the 99 cases reported herein demonstrated calcification, suggesting that calcification within a renal mass might also warrant operative diagnostic confirmation regardless of the other findings. The suggested criteria for accurate nonsurgical diagnosis of benign avascular or cystic lesions are summarized as follows: 1. Strictly benign,
2. 3. 4. 5.
avascular cystic lesion, by nephrotomography and/or selective renal arteriography. Absence of any calcification. Normal ultrasound (B-mode sonography) study. Smooth-walled unilocular simple cyst of less than 18 cm., by contrast cystography. Clear aspirated cystic fluid with negative findings on cytologic examination.
Only when all these criteria are met, can we be secure in the nonsurgical diagnosis of a benign renal lesion. If these criteria cannot be met unequivocally, surgical exploration is mandatory. Complacency may result in overlooking malignancy in the patient with known polycystic renal diseases - 8 cases reported here bring the total reported in the literature to about 40.‘7-‘g Five of 7 cases of polycystic related renal cell carcinomas in this series occurred in patients under age forty-one. Only on several occasions has malignancy been suspected antemortem or prior to surgery among the reported cases. Whether or not polycystic disease per se predisposes to malignancy remains an unanswered question. Gibson15 defined the possible relationships that exist between solitary cysts of the kidney and malignant tumors: (1) unrelated origin; (2) origin of cyst within a tumor; (3) origin of tumor within a cyst; and (4) origin of a cyst distal to a tumor. Fifty-five of 62 (89 per cent) cases of coexisting malignancies and simple cysts reported
UROLOGY
I
AUGUST 1976 I
VOLUME
VIII,
NUMBER
2
here have been shown to be anatomically closely related, supporting a cause and effect relationship. Gibson’s hypothesis that malignancy can fulfill Hepler’s two prerequisites to cyst formation, tissue ischemia and collecting system obstruction, could explain the observed relationship. Only 7 of the 99 cases of coexisting avascular lesions and renal cell carcinoma can be said to be coincidental and unrelated.
8.
9. 10.
Lackland AFB, Texas 78236 11. References 1. WALSH, A.: Solitary cyst of the kidney and its relationship to renal &our, Br. J. Ural: 23: 377 (1951). 2. EMMETT, J. L., LEVINE, S. R., and WOOLNER, L. B.: Co-existence of renal cyst and tumour; incidence in 1,667 cases, ibid. 35: 403 (1963). 3. BRANNAN, W., MILLER, W., and CRISLER, M.: Coexistence of renal neoplasms and renal cysts, South. Med. J. 155: 749 (1962). 4. WEISS, R. M., BECKER, J. A., DAVIDSON, A. J., and appearance of renal LYTTON, B. : Angiographic papillary-tubular adenocarcinoma, J. Ural. 102: 661 (1969). 5. BENNINGTON, J. L.: Proceedings: Cancer of the kidney etiology, epidemiology, and pathology, Cancer 32: 1017 (1973). 6. MCLAUGHLIN, A. P., III, TALNER, L. B., LEOPOLD, B. R., and MCCULLOUGH, D. L.: Avascular plsimary renal cell carcinoma: varied pathologic and hngiographic features, J. Urol. 111: 587 (1974). Assessment of avascular mass 7. LANG, E. K., et al.:
UROLOGY
/ AUGUST 1976 /
VOLUME VIII, NUMBER 2
12.
13.
14. 15. 16. 17.
18.
19.
lesions: the use of nephrotomography, arteriography, cyst puncture, double contrast study, and histochemical and histopathologic examination of aspirate, South. Med. J. 65: l(l972). ASHER, W. M., and LEOPOLD, G. R. : A streamlined diagnostic approach to renal mass lesions with renal echogram, J: Urol. 108: 205 (1972). POLLACK, H. M., GOLDBERG, B. B., and BOGASH, T. M.: Changing concepts in the diagnosis and management of renal cysts, ibid. 111: 326 (1974). ROMEISER, R. S., WALLS, W. J., and VALK, W. L.: B-scan ultrasound in the evaluation of renal mass lesions, ibid. 112: 9 (1974). REHN, R. A., TAYLOR, W. N., and TAYLOR, J. N.: Renal cyst associated with carcinoma, ibid. 86: 307 (1961). CASARELLA, W. J., VONMICSKY, L. T., and LALLI, A. F. : Latest advances in diagnostic urologic radiology, Urology 1: 501; 506; 523 (1973). VONSCHREEB, T., ARNER, O., SKOUSTED, G., and WIKSTAD, N.: Renal adenocarcinoma. Is there a risk of spreading tumor cells in diagnostic puncture? Stand. J. Urol. Nephrol. 1: 270 (1967). JACKMAN, R. J., and STEVENS, G. M.: Benign hemorrhagic renal cyst, Radiology 110: 7 (1974). GIBSON, T. E.: Inter-relationship of renal cysts and tumors: report of three cases, J. Urol. 71: 241 (1954). DANIEL, W. W., JR., et al.: Calcified renal masses, Radiology 103: 503 (1972). HOWARD, R. M., and YOUNG, J. D., JR.: Two malignant tumors in a polycystic kidney, J. Ural. 102: 162 (1969). MCFARLAND, W. L., WALLACE, S., and JOHNSON, D. E.: Renal carcinoma and polycystic kidney, ibid. 107: 530 (1972). ROBERTS, P. F.: Bilateral renal carcinoma associated with polycystic kidneys, Br. Med. J. 3: 273 (1973).
187
