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Outcome of surgery in cystic renal cell carcinoma
ADULT UROLOGY
OUTCOME OF SURGERY IN CYSTIC RENAL CELL CARCINOMA SHIGEHIKO KOGA, MASAHARU NISHIKIDO, TOMAYOSHI HAYASHI, FUKUZO MATSUYA, YUTAKA SAITO, AND HIROSHI KANETAKE
ABSTRACT Objectives. To review cases of cystic renal cell carcinoma treated surgically at our institution and define their clinical and histopathologic features. Methods. Between 1986 and 1998, 21 patients with cystic renal cell carcinoma were treated surgically. Cystic renal cell carcinoma was categorized using Hartman’s classification. Results. Histopathologic examination demonstrated cystic necrosis in 11 patients, multilocular cystic renal cell carcinoma in 9, and unilocular cystic renal cell carcinoma in 1 patient. Tumors were incidentally found during an evaluation of unrelated disease or a general health checkup in 14 patients (67%). The mean tumor size was 5.6 cm (range 0.5 to 12) for cystic necrosis and 5.4 cm (range 2 to 9) for multilocular cystic renal cell carcinoma. All 9 cases of multilocular cystic renal cell carcinoma were of the clear cell type and tumor grade 1. The mean follow-up period was 65 months (range 9 to 141). The 5-year disease-specific survival rates for multilocular cystic renal cell carcinoma and cystic necrosis were 100% and 80%, respectively. Conclusions. The prognosis for patients with cystic renal cell carcinoma is better than that for patients with solid tumors. In particular, the prognosis of multilocular cystic renal cell carcinoma is excellent. Multilocular cystic renal cell carcinoma represents a distinct subtype of renal cell carcinoma that can be completely cured by surgery. UROLOGY 56: 67–70, 2000. © 2000, Elsevier Science Inc.
R
ecent advances in imaging diagnostic procedures have facilitated the identification of cystic renal lesions. However, it is often difficult to differentiate cystic renal cell carcinoma from benign cystic lesions and other malignant cystic tumors.1,2 In most cases, a definite diagnosis can only be established by histopathologic examination. Approximately 4% to 15% of renal cell carcinomas show a cystic pattern.3– 6 Several mechanisms may explain the cystic nature of renal cell carcinoma. According to Hartman et al.,7 these mechanisms include the following: intrinsic multiloculated growth, intrinsic unilocular growth, cystic necrosis, and origin from the epithelial lining in a preexisting simple cyst. However, the nature of cystic renal cell carcinoma has not been clearly delineated. In the present report, we reviewed cases of From the Department of Urology, Nagasaki University School of Medicine and Department of Pathology, Nagasaki University Hospital, Nagasaki, Japan Reprint requests: Shigehiko Koga, M.D., Department of Urology, Nagasaki University School of Medicine, Nagasaki City, Nagasaki 852-8501, Japan Submitted: November 22, 1999, accepted (with revisions): February 10, 2000 © 2000, ELSEVIER SCIENCE INC. ALL RIGHTS RESERVED
cystic renal cell carcinoma surgically treated in our hospital to evaluate the clinical and pathologic features of these tumors. MATERIAL AND METHODS Between 1986 and 1998, 21 patients with cystic renal cell carcinoma were surgically treated at our institution, and all relevant clinical data were retrieved from the medical records. All cases were recognizable as cystic renal mass lesions by ultrasound and computed tomography, and a provisional diagnosis of renal cell carcinoma was made preoperatively in all cases. All cases were solitary, and tissue specimens were obtained during radical or partial nephrectomy. Three pathologists classified the lesions as cystic necrosis, multilocular cystic renal cell carcinoma, or unilocular cystic renal cell carcinoma on the basis of the criteria defined by Hartman et al.7 at the time of the initial tissue evaluation. Another pathologist (T.H.) reviewed all the slides of the original specimens and confirmed the diagnosis. Cystic renal cell carcinoma represented lesions in which the cystic component constituted 75% or more of the resected tumor according to the pathologic records. The percentage of the cystic component was obtained by subtracting the solid component from the total tumor area. Tumor stage was assessed according to the 1997 TNM classification.8 The tumor nuclear grade was assessed with the grading system of Fuhrman et al.9 Tumor size was determined by measuring the longest diameter of the surgical specimens. For statistical analysis, Kaplan-Meier survival curves were con0090-4295/00/$20.00 PII S0090-4295(00)00540-9 67
TABLE I. Clinical and pathologic findings Pt. No.
Presentation
Treatment
Cell Type
Tumor Grade
Hartman’s Classification
Stage
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
Abdominal mass Abdominal mass Abdominal mass Hematuria Incidentally found Incidentally found Incidentally found Incidentally found Abdominal mass Incidentally found Incidentally found Incidentally found Incidentally found Incidentally found Incidentally found Metastasis Incidentally found Incidentally found Incidentally found Hematuria Incidentally found
Partial nephrectomy Nephrectomy Nephrectomy Nephrectomy Nephrectomy Nephrectomy Nephrectomy Nephrectomy Nephrectomy Nephrectomy Partial nephrectomy Nephrectomy Nephrectomy Nephrectomy Nephrectomy Nephrectomy Nephrectomy Nephrectomy Nephrectomy Nephrectomy Nephrectomy
Granular cell Clear cell Clear cell Clear cell Clear cell Clear cell Clear cell Clear cell Granular cell Clear cell Clear cell Clear cell Clear cell Clear cell Clear cell Clear cell Clear cell Clear cell Clear cell Clear cell Clear cell
2 1 2 1 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 2 2
Unilocular Cystic necrosis Cystic necrosis Cystic necrosis MCRCC MCRCC Cystic necrosis MCRCC Cystic necrosis Cystic necrosis Cystic necrosis MCRCC MCRCC MCRCC Cystic necrosis Cystic necrosis MCRCC MCRCC MCRCC Cystic necrosis Cystic necrosis
T2N0M0 T2N0M0 T2N0M0 T1N0M0 T1N0M0 T2N0M0 T1N0M0 T1N0M0 T1N0M0 T2N0M0 T1N0M0 T1N0M0 T1N0M0 T1N0M0 T1N0M0 T2N0M1 T1N0M0 T1N0M0 T1N0M0 T1N0M0 T1N0M0
KEY: Pt. No. ⫽ patient number; Unilocular ⫽ unilocular cystic renal cell carcinoma; MCRCC ⫽ multilocular cystic renal cell carcinoma.
structed from the date of surgery to the end point of diseasespecific survival, which referred to the interval until death due to renal cell carcinoma. Survival curves were compared by the log-rank test.10
RESULTS The clinical and pathologic findings are summarized in Table I. The study group included 16 men with a mean age of 60.4 years (range 41 to 82) and 5 women with a mean age of 54.4 years (range 28 to 70). The mean follow-up period was 65 months (range 9 to 141). Tumors were incidentally found during the evaluation of unrelated diseases or a general health checkup in 14 patients (67%). Four patients (19%) presented with an abdominal mass, 2 (10%) with gross hematuria, and 1 (5%) with metastatic lesions. All 21 patients with cystic renal cell carcinoma were surgically treated (radical nephrectomy in 19 and partial nephrectomy in 2). Histopathologic examination of the 21 specimens revealed cystic necrosis in 11, multilocular cystic renal cell carcinoma in 9, and unilocular cystic renal cell carcinoma in 1 (Hartman’s classification of cystic renal cell carcinoma). The mean tumor size was 5.6 cm (range 0.5 to 12) in cystic necrosis and 5.4 cm (range 2 to 9) in multilocular cystic renal cell carcinoma. There were 12 rightsided and 9 left-sided tumors. The histologic cell type was clear cell in 19 and granular cell in 2. The classification according to the tumor nuclear grading system showed 16 carcinomas (76%) of tumor 68
nuclear grade 1 and 5 (24%) of tumor nuclear grade 2. All 9 cases of multilocular cystic renal cell carcinoma were the clear cell type and tumor grade 1. The stage (TNM classification) was T1N0M0 in 15 patients (71%), T2N0M0 in 5 patients (24%), and T2N0M1 in 1 patient (5%) who had lung and bone metastases. The 5 and 10-year disease-specific survival rate for the 9 patients with multilocular cystic renal cell carcinoma was 100% and 100%, respectively, and no patient had metastasis or local recurrence. The 5-year disease-specific survival rate for 11 patients with cystic necrosis was 80%. The survival rate of patients with multilocular cystic renal cell carcinoma was significantly higher than that of patients with cystic necrosis (log-rank test, P ⫽ 0.02) (Fig. 1). COMMENT Renal cell carcinoma rarely displays cystic formation, although the etiology of such cysts is not clear at present. Gibson11 divided patients with renal cell carcinoma and renal cyst into four groups. However, detailed microscopic findings were not described in that report. Hartman et al.7 divided cystic renal cell carcinomas into four histopathologic groups: (a) intrinsic multiloculated growth, (b) intrinsic unilocular growth, (c) cystic necrosis, and (d) origin from the epithelial lining in a preexisting simple cysts. In their study, multilocular UROLOGY 56 (1), 2000
FIGURE 1. Kaplan-Meier disease-specific survival curves of patients with multilocular cystic renal cell carcinoma (MCRCC, n ⫽ 9; thick line) and cystic necrosis (n ⫽ 11; thin line). (Log-rank test, P ⫽ 0.02.)
cystic renal cell carcinoma (intrinsic multiloculated growth) was a distinct subtype of renal cell carcinoma. It was characterized by variable-size, noncommunicating cysts separated by irregular, thick, and fibrous septa, which were microscopically covered with clear cells containing small hyperchromatic nuclei. Our analysis showed that the clinical features of cystic renal cell carcinoma were similar to those of solid renal cell carcinoma. The signs and symptoms included the presence of a flank mass, abdominal pain, and hematuria. The frequency of symptomatic metastases at the time of presentation was lower than that encountered in renal cell carcinoma in general. All our cases of multilocular cystic renal cell carcinoma were low-stage and low-grade malignancies, and none developed metastatic disease or tumor recurrence. The prognosis of cystic renal cell carcinoma was excellent, as the 5-year disease-specific survival for solid renal cell carcinoma is 55% at our institution. Multilocular cystic renal cell carcinoma included 2 cases (22%) with a tumor size exceeding 7 cm in diameter. Although a significant difference in the survival rate exists between Stage I and Stage II tumors for the 1997 TNM stage classification, tumor size seems to be less important in patients with multilocular cystic renal cell carcinoma.12 Tosaka et al.13 reviewed Japanese reports of multilocular cystic renal cell carcinomas and multilocular cystic nephromas associated with renal cell carcinoma. They reported that the 10-year survival rate of 38 patients with mixed multilocular cystic renal disease was 97%. Corica et al.14 also reported that 22 (92%) of 24 patients with cystic renal cell carcinoma (including 18 patients with multilocular cystic renal cell carcinoma) showed UROLOGY 56 (1), 2000
no evidence of recurrence. These results are similar to those reported in our study. The histologic findings of clear cells in the cyst wall were based on the diagnosis of renal cell carcinoma. Recently, Kirsh et al.15 histologically re-examined clear cell cystic lesions of the kidney and proposed that clear cell multicystic renal disease may represent a distinct benign neoplasm.16 In this regard, DNA ploidy analysis of multilocular cystic renal cell carcinoma has shown diploidy, and our clinical data in the present study add support to the theory.3,14 However, further studies are necessary to establish whether clear cells in multilocular cystic renal cell carcinomas have a nonmalignant or less malignant potential. Compared with solid renal tumors, these cystic tumors contain fewer malignant cells and have a lower nuclear grade. Therefore, such cystic lesions may proliferate slowly. The use of nephron-sparing surgery in patients with renal cell carcinoma and a solitary kidney or those with reduced renal function is generally accepted. However, opinions differ concerning performing such surgery in patients with renal cell carcinoma and a normal contralateral kidney. Lerner et al.17 reported that the clinical outcome after nephron-sparing surgery was as good as after radical nephrectomy in patients with conventional renal cell carcinoma measuring 4 cm or less in diameter but worse among those with tumors greater than 4 cm in diameter. On the other hand, Smith18 commented that in the presence of a normal contralateral kidney, partial nephrectomy should not be performed even for cystic renal cell carcinoma if surgical margins were precarious or compromised. When the prognosis and histopathologic findings of multilocular cystic renal cell carcinoma are considered, the use of nephron-sparing surgery may be an optional therapy. In particular, nephron-sparing surgery is recommended when the diagnosis of a complex renal cyst is uncertain. CONCLUSIONS Although the population sample was relatively small in the present study, our results demonstrated a high survival rate in patients with cystic renal cell carcinoma. In particular, the prognosis of multilocular cystic renal cell carcinoma is excellent. Our results indicated that multilocular cystic renal cell carcinoma is an important subtype of renal cell carcinoma that is distinct from solid renal cell carcinoma. REFERENCES 1. Cloix P, Martin X, Pangaud P, et al: Surgical management of complex renal cysts: a series of 32 cases. J Urol 156: 28 –30, 1996. 69
2. Bosniak MA: The current radiological approach to renal cysts. Radiology 158: 1–10, 1986. 3. Murad T, Komaiko W, Oyasu R, et al: Multilocular cystic renal cell carcinoma. Am J Clin Pathol 95: 633– 637, 1991. 4. Emmett JL, Levine SR, and Woolner LB: Co-existence of renal cyst and tumor: incidence in 1,007 cases. Br J Urol 35: 403– 410, 1963. 5. Wills J: Cystic adenocarcinoma of the kidney mimicking multilocular renal cyst. Urol Radiol 5: 51–53, 1983. 6. Hayakawa M, Hatano T, Tsuji A, et al: Patients with renal cysts associated with renal cell carcinoma and the clinical implications of cyst puncture: a study of 223 cases. Urology 47: 643– 646, 1996. 7. Hartman DS, Davis CJ Jr, Johns T, et al: Cystic renal cell carcinoma. Urology 28: 145–153, 1986. 8. Sobin LH, and Witterkind CH: TNM Classification of Malignant Tumors, 5th ed. New York, Wiley, 1997, pp 180 –182. 9. Fuhrman SA, Lasky LC, and Limas C: Prognostic significance of morphologic parameters in renal cell carcinoma. Am J Surg Pathol 6: 655– 663, 1982. 10. Kaplan EL, and Meier P: Nonparametric estimation from incomplete observations. J Am Stat Assoc 53: 457– 481, 1958. 11. Gibson TE: Interrelationship of renal cysts and tumors: report of three cases. J Urol 71: 241–252, 1954.
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12. Javidan J, Stricker HJ, and Tamboli P, et al: Prognostic significance of the 1997 TNM classification of renal cell carcinoma. J Urol 162: 1277–1281, 1999. 13. Tosaka A, Yoshida K, Kobayashi N, et al: A report of two cases of multilocular cystic renal cell carcinoma: review of 51 cases reported and the results of a prognostic survey. Hinyokika Kiyo 38: 1045–1050, 1992. 14. Corica FA, Iczkowski KA, Cheng L, et al: Cystic renal cell carcinoma is cured by resection: a study of 24 cases with long-term followup. J Urol 161: 408 – 411, 1999. 15. Kirsh EJ, Straus FH II, Goldfischer ER, et al: Benign adenomatous multicystic kidney tumor (Perlmann’s tumor) and renal cortical carcinoma with adenomatous multicystic features: 12 cases. Urology 53: 65–70, 1999. 16. Robinson GL: Perlmann’s tumor of the kidney. Br J Surg 44: 620 – 623, 1957. 17. Lerner SE, Hawkins CA, and Blute ML, et al: Disease outcome in patients with low stage renal cell carcinoma treated with nephron sparing or radical surgery. J Urol 155: 1868 –1873, 1996. 18. Smith JA Jr: Cystic renal cell carcinoma is cured by resection: a study of 24 cases with long-term followup (editorial comment). J Urol 161: 411, 1999.
UROLOGY 56 (1), 2000
OUTCOME OF SURGERY IN CYSTIC RENAL CELL CARCINOMA SHIGEHIKO KOGA, MASAHARU NISHIKIDO, TOMAYOSHI HAYASHI, FUKUZO MATSUYA, YUTAKA SAITO, AND HIROSHI KANETAKE
ABSTRACT Objectives. To review cases of cystic renal cell carcinoma treated surgically at our institution and define their clinical and histopathologic features. Methods. Between 1986 and 1998, 21 patients with cystic renal cell carcinoma were treated surgically. Cystic renal cell carcinoma was categorized using Hartman’s classification. Results. Histopathologic examination demonstrated cystic necrosis in 11 patients, multilocular cystic renal cell carcinoma in 9, and unilocular cystic renal cell carcinoma in 1 patient. Tumors were incidentally found during an evaluation of unrelated disease or a general health checkup in 14 patients (67%). The mean tumor size was 5.6 cm (range 0.5 to 12) for cystic necrosis and 5.4 cm (range 2 to 9) for multilocular cystic renal cell carcinoma. All 9 cases of multilocular cystic renal cell carcinoma were of the clear cell type and tumor grade 1. The mean follow-up period was 65 months (range 9 to 141). The 5-year disease-specific survival rates for multilocular cystic renal cell carcinoma and cystic necrosis were 100% and 80%, respectively. Conclusions. The prognosis for patients with cystic renal cell carcinoma is better than that for patients with solid tumors. In particular, the prognosis of multilocular cystic renal cell carcinoma is excellent. Multilocular cystic renal cell carcinoma represents a distinct subtype of renal cell carcinoma that can be completely cured by surgery. UROLOGY 56: 67–70, 2000. © 2000, Elsevier Science Inc.
R
ecent advances in imaging diagnostic procedures have facilitated the identification of cystic renal lesions. However, it is often difficult to differentiate cystic renal cell carcinoma from benign cystic lesions and other malignant cystic tumors.1,2 In most cases, a definite diagnosis can only be established by histopathologic examination. Approximately 4% to 15% of renal cell carcinomas show a cystic pattern.3– 6 Several mechanisms may explain the cystic nature of renal cell carcinoma. According to Hartman et al.,7 these mechanisms include the following: intrinsic multiloculated growth, intrinsic unilocular growth, cystic necrosis, and origin from the epithelial lining in a preexisting simple cyst. However, the nature of cystic renal cell carcinoma has not been clearly delineated. In the present report, we reviewed cases of From the Department of Urology, Nagasaki University School of Medicine and Department of Pathology, Nagasaki University Hospital, Nagasaki, Japan Reprint requests: Shigehiko Koga, M.D., Department of Urology, Nagasaki University School of Medicine, Nagasaki City, Nagasaki 852-8501, Japan Submitted: November 22, 1999, accepted (with revisions): February 10, 2000 © 2000, ELSEVIER SCIENCE INC. ALL RIGHTS RESERVED
cystic renal cell carcinoma surgically treated in our hospital to evaluate the clinical and pathologic features of these tumors. MATERIAL AND METHODS Between 1986 and 1998, 21 patients with cystic renal cell carcinoma were surgically treated at our institution, and all relevant clinical data were retrieved from the medical records. All cases were recognizable as cystic renal mass lesions by ultrasound and computed tomography, and a provisional diagnosis of renal cell carcinoma was made preoperatively in all cases. All cases were solitary, and tissue specimens were obtained during radical or partial nephrectomy. Three pathologists classified the lesions as cystic necrosis, multilocular cystic renal cell carcinoma, or unilocular cystic renal cell carcinoma on the basis of the criteria defined by Hartman et al.7 at the time of the initial tissue evaluation. Another pathologist (T.H.) reviewed all the slides of the original specimens and confirmed the diagnosis. Cystic renal cell carcinoma represented lesions in which the cystic component constituted 75% or more of the resected tumor according to the pathologic records. The percentage of the cystic component was obtained by subtracting the solid component from the total tumor area. Tumor stage was assessed according to the 1997 TNM classification.8 The tumor nuclear grade was assessed with the grading system of Fuhrman et al.9 Tumor size was determined by measuring the longest diameter of the surgical specimens. For statistical analysis, Kaplan-Meier survival curves were con0090-4295/00/$20.00 PII S0090-4295(00)00540-9 67
TABLE I. Clinical and pathologic findings Pt. No.
Presentation
Treatment
Cell Type
Tumor Grade
Hartman’s Classification
Stage
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
Abdominal mass Abdominal mass Abdominal mass Hematuria Incidentally found Incidentally found Incidentally found Incidentally found Abdominal mass Incidentally found Incidentally found Incidentally found Incidentally found Incidentally found Incidentally found Metastasis Incidentally found Incidentally found Incidentally found Hematuria Incidentally found
Partial nephrectomy Nephrectomy Nephrectomy Nephrectomy Nephrectomy Nephrectomy Nephrectomy Nephrectomy Nephrectomy Nephrectomy Partial nephrectomy Nephrectomy Nephrectomy Nephrectomy Nephrectomy Nephrectomy Nephrectomy Nephrectomy Nephrectomy Nephrectomy Nephrectomy
Granular cell Clear cell Clear cell Clear cell Clear cell Clear cell Clear cell Clear cell Granular cell Clear cell Clear cell Clear cell Clear cell Clear cell Clear cell Clear cell Clear cell Clear cell Clear cell Clear cell Clear cell
2 1 2 1 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 2 2
Unilocular Cystic necrosis Cystic necrosis Cystic necrosis MCRCC MCRCC Cystic necrosis MCRCC Cystic necrosis Cystic necrosis Cystic necrosis MCRCC MCRCC MCRCC Cystic necrosis Cystic necrosis MCRCC MCRCC MCRCC Cystic necrosis Cystic necrosis
T2N0M0 T2N0M0 T2N0M0 T1N0M0 T1N0M0 T2N0M0 T1N0M0 T1N0M0 T1N0M0 T2N0M0 T1N0M0 T1N0M0 T1N0M0 T1N0M0 T1N0M0 T2N0M1 T1N0M0 T1N0M0 T1N0M0 T1N0M0 T1N0M0
KEY: Pt. No. ⫽ patient number; Unilocular ⫽ unilocular cystic renal cell carcinoma; MCRCC ⫽ multilocular cystic renal cell carcinoma.
structed from the date of surgery to the end point of diseasespecific survival, which referred to the interval until death due to renal cell carcinoma. Survival curves were compared by the log-rank test.10
RESULTS The clinical and pathologic findings are summarized in Table I. The study group included 16 men with a mean age of 60.4 years (range 41 to 82) and 5 women with a mean age of 54.4 years (range 28 to 70). The mean follow-up period was 65 months (range 9 to 141). Tumors were incidentally found during the evaluation of unrelated diseases or a general health checkup in 14 patients (67%). Four patients (19%) presented with an abdominal mass, 2 (10%) with gross hematuria, and 1 (5%) with metastatic lesions. All 21 patients with cystic renal cell carcinoma were surgically treated (radical nephrectomy in 19 and partial nephrectomy in 2). Histopathologic examination of the 21 specimens revealed cystic necrosis in 11, multilocular cystic renal cell carcinoma in 9, and unilocular cystic renal cell carcinoma in 1 (Hartman’s classification of cystic renal cell carcinoma). The mean tumor size was 5.6 cm (range 0.5 to 12) in cystic necrosis and 5.4 cm (range 2 to 9) in multilocular cystic renal cell carcinoma. There were 12 rightsided and 9 left-sided tumors. The histologic cell type was clear cell in 19 and granular cell in 2. The classification according to the tumor nuclear grading system showed 16 carcinomas (76%) of tumor 68
nuclear grade 1 and 5 (24%) of tumor nuclear grade 2. All 9 cases of multilocular cystic renal cell carcinoma were the clear cell type and tumor grade 1. The stage (TNM classification) was T1N0M0 in 15 patients (71%), T2N0M0 in 5 patients (24%), and T2N0M1 in 1 patient (5%) who had lung and bone metastases. The 5 and 10-year disease-specific survival rate for the 9 patients with multilocular cystic renal cell carcinoma was 100% and 100%, respectively, and no patient had metastasis or local recurrence. The 5-year disease-specific survival rate for 11 patients with cystic necrosis was 80%. The survival rate of patients with multilocular cystic renal cell carcinoma was significantly higher than that of patients with cystic necrosis (log-rank test, P ⫽ 0.02) (Fig. 1). COMMENT Renal cell carcinoma rarely displays cystic formation, although the etiology of such cysts is not clear at present. Gibson11 divided patients with renal cell carcinoma and renal cyst into four groups. However, detailed microscopic findings were not described in that report. Hartman et al.7 divided cystic renal cell carcinomas into four histopathologic groups: (a) intrinsic multiloculated growth, (b) intrinsic unilocular growth, (c) cystic necrosis, and (d) origin from the epithelial lining in a preexisting simple cysts. In their study, multilocular UROLOGY 56 (1), 2000
FIGURE 1. Kaplan-Meier disease-specific survival curves of patients with multilocular cystic renal cell carcinoma (MCRCC, n ⫽ 9; thick line) and cystic necrosis (n ⫽ 11; thin line). (Log-rank test, P ⫽ 0.02.)
cystic renal cell carcinoma (intrinsic multiloculated growth) was a distinct subtype of renal cell carcinoma. It was characterized by variable-size, noncommunicating cysts separated by irregular, thick, and fibrous septa, which were microscopically covered with clear cells containing small hyperchromatic nuclei. Our analysis showed that the clinical features of cystic renal cell carcinoma were similar to those of solid renal cell carcinoma. The signs and symptoms included the presence of a flank mass, abdominal pain, and hematuria. The frequency of symptomatic metastases at the time of presentation was lower than that encountered in renal cell carcinoma in general. All our cases of multilocular cystic renal cell carcinoma were low-stage and low-grade malignancies, and none developed metastatic disease or tumor recurrence. The prognosis of cystic renal cell carcinoma was excellent, as the 5-year disease-specific survival for solid renal cell carcinoma is 55% at our institution. Multilocular cystic renal cell carcinoma included 2 cases (22%) with a tumor size exceeding 7 cm in diameter. Although a significant difference in the survival rate exists between Stage I and Stage II tumors for the 1997 TNM stage classification, tumor size seems to be less important in patients with multilocular cystic renal cell carcinoma.12 Tosaka et al.13 reviewed Japanese reports of multilocular cystic renal cell carcinomas and multilocular cystic nephromas associated with renal cell carcinoma. They reported that the 10-year survival rate of 38 patients with mixed multilocular cystic renal disease was 97%. Corica et al.14 also reported that 22 (92%) of 24 patients with cystic renal cell carcinoma (including 18 patients with multilocular cystic renal cell carcinoma) showed UROLOGY 56 (1), 2000
no evidence of recurrence. These results are similar to those reported in our study. The histologic findings of clear cells in the cyst wall were based on the diagnosis of renal cell carcinoma. Recently, Kirsh et al.15 histologically re-examined clear cell cystic lesions of the kidney and proposed that clear cell multicystic renal disease may represent a distinct benign neoplasm.16 In this regard, DNA ploidy analysis of multilocular cystic renal cell carcinoma has shown diploidy, and our clinical data in the present study add support to the theory.3,14 However, further studies are necessary to establish whether clear cells in multilocular cystic renal cell carcinomas have a nonmalignant or less malignant potential. Compared with solid renal tumors, these cystic tumors contain fewer malignant cells and have a lower nuclear grade. Therefore, such cystic lesions may proliferate slowly. The use of nephron-sparing surgery in patients with renal cell carcinoma and a solitary kidney or those with reduced renal function is generally accepted. However, opinions differ concerning performing such surgery in patients with renal cell carcinoma and a normal contralateral kidney. Lerner et al.17 reported that the clinical outcome after nephron-sparing surgery was as good as after radical nephrectomy in patients with conventional renal cell carcinoma measuring 4 cm or less in diameter but worse among those with tumors greater than 4 cm in diameter. On the other hand, Smith18 commented that in the presence of a normal contralateral kidney, partial nephrectomy should not be performed even for cystic renal cell carcinoma if surgical margins were precarious or compromised. When the prognosis and histopathologic findings of multilocular cystic renal cell carcinoma are considered, the use of nephron-sparing surgery may be an optional therapy. In particular, nephron-sparing surgery is recommended when the diagnosis of a complex renal cyst is uncertain. CONCLUSIONS Although the population sample was relatively small in the present study, our results demonstrated a high survival rate in patients with cystic renal cell carcinoma. In particular, the prognosis of multilocular cystic renal cell carcinoma is excellent. Our results indicated that multilocular cystic renal cell carcinoma is an important subtype of renal cell carcinoma that is distinct from solid renal cell carcinoma. REFERENCES 1. Cloix P, Martin X, Pangaud P, et al: Surgical management of complex renal cysts: a series of 32 cases. J Urol 156: 28 –30, 1996. 69
2. Bosniak MA: The current radiological approach to renal cysts. Radiology 158: 1–10, 1986. 3. Murad T, Komaiko W, Oyasu R, et al: Multilocular cystic renal cell carcinoma. Am J Clin Pathol 95: 633– 637, 1991. 4. Emmett JL, Levine SR, and Woolner LB: Co-existence of renal cyst and tumor: incidence in 1,007 cases. Br J Urol 35: 403– 410, 1963. 5. Wills J: Cystic adenocarcinoma of the kidney mimicking multilocular renal cyst. Urol Radiol 5: 51–53, 1983. 6. Hayakawa M, Hatano T, Tsuji A, et al: Patients with renal cysts associated with renal cell carcinoma and the clinical implications of cyst puncture: a study of 223 cases. Urology 47: 643– 646, 1996. 7. Hartman DS, Davis CJ Jr, Johns T, et al: Cystic renal cell carcinoma. Urology 28: 145–153, 1986. 8. Sobin LH, and Witterkind CH: TNM Classification of Malignant Tumors, 5th ed. New York, Wiley, 1997, pp 180 –182. 9. Fuhrman SA, Lasky LC, and Limas C: Prognostic significance of morphologic parameters in renal cell carcinoma. Am J Surg Pathol 6: 655– 663, 1982. 10. Kaplan EL, and Meier P: Nonparametric estimation from incomplete observations. J Am Stat Assoc 53: 457– 481, 1958. 11. Gibson TE: Interrelationship of renal cysts and tumors: report of three cases. J Urol 71: 241–252, 1954.
70
12. Javidan J, Stricker HJ, and Tamboli P, et al: Prognostic significance of the 1997 TNM classification of renal cell carcinoma. J Urol 162: 1277–1281, 1999. 13. Tosaka A, Yoshida K, Kobayashi N, et al: A report of two cases of multilocular cystic renal cell carcinoma: review of 51 cases reported and the results of a prognostic survey. Hinyokika Kiyo 38: 1045–1050, 1992. 14. Corica FA, Iczkowski KA, Cheng L, et al: Cystic renal cell carcinoma is cured by resection: a study of 24 cases with long-term followup. J Urol 161: 408 – 411, 1999. 15. Kirsh EJ, Straus FH II, Goldfischer ER, et al: Benign adenomatous multicystic kidney tumor (Perlmann’s tumor) and renal cortical carcinoma with adenomatous multicystic features: 12 cases. Urology 53: 65–70, 1999. 16. Robinson GL: Perlmann’s tumor of the kidney. Br J Surg 44: 620 – 623, 1957. 17. Lerner SE, Hawkins CA, and Blute ML, et al: Disease outcome in patients with low stage renal cell carcinoma treated with nephron sparing or radical surgery. J Urol 155: 1868 –1873, 1996. 18. Smith JA Jr: Cystic renal cell carcinoma is cured by resection: a study of 24 cases with long-term followup (editorial comment). J Urol 161: 411, 1999.
UROLOGY 56 (1), 2000