COLLECTING DUCT RENAL CELL CARCINOMA: CLINICAL STUDY OF A RARE TUMOR DEBBY CHAO, AMNON ZISMAN, ALLAN J. PANTUCK, BARBARA J. GITLITZ, STEPHEN J. FREEDLAND, JONATHAN W. SAID, ROBERT A. FIGLIN AND ARIE S. BELLDEGRUN From the Department of Urology, Division of Urologic Oncology, Department of Medicine, Division of Hematology-Oncology, Department of Pathology and Laboratory Medicine, University of California School of Medicine, Los Angeles, Los Angeles, California ABSTRACT Purpose: Collecting duct carcinoma is a rare type of renal cell carcinoma that affects younger patients, and is associated with aggressive regional and distant spread. The clinical and patho- logical features of 6 patients with collecting duct carcinoma treated at a single institution are described. Materials and Methods: There were 6 patients with collecting duct carcinoma included in the University of California School of Medicine, Los Angeles, Kidney Cancer Database. Demographic, clinical, pathological and survival data were gathered. Results: Average patient age plus or minus standard deviation was 56  11 years, and 5 of 6 had TNM stage IV disease. The average survival of these patients was 11.5 months (range 7 to 17). There was 1 patient who had TNM stage I disease and survived without evidence of disease at 5 years. Transient response to chemotherapy was seen in 1 patient. Conclusions: Collecting duct carcinoma is associated with poor prognosis. For the majority of patients surgical treatment will not result in a cure. Previously recommended chemotherapy and/or immunotherapy appears to have a limited role in treatment of this disease, and early detection may be the best method for prolonging patient survival. KEY WORDS: kidney; carcinoma; carcinoma, renal cell Collecting duct carcinoma of the kidney, including Bellini tumor, is a rare histological type of renal cell carcinoma with distinctive clinical and histopathological features. Unlike the majority of renal cell carcinoma tumors that occur in the epithelial cells of the proximal tubules, collecting duct carci- noma originates in the distal collecting ducts. 1 Grossly, the tumor is often centrally located in or near the region of the renal pelvis and appears gray or white without extensive necrosis or hemorrhage. Various histological patterns can be found in the same tumor but most collecting duct carcinomas demonstrate varying amounts of duct-like or papillary archi- tecture surrounded by desmoplastic stroma. Cellular appear- ance is usually nondiagnostic, although granular or eosino- philic cytoplasm, cuboidal or columnar shape, and atypical nuclei containing large nucleoli have been described. Occa- sionally, columnar cells take on a hobnail appearance. Collecting ducts near the tumor often show dysplastic or hyperplastic changes (see figure). 1–4 The papillary appear- ance of collecting duct carcinoma can sometimes make dis- tinction from papillary renal cell carcinoma difficult and immunohistochemical studies may be required to make a definitive diagnosis. 2, 3 Characteristically, collecting duct carcinoma reacts positively with antibodies to high molecular weight cytokeratins and lectins that are widely expressed antigens in cells of the distal tubules. Vimentin reactivity is usually negative or weakly positive. In contrast, most renal cell carcinoma reacts positively with the antibodies to low molecular weight cytokeratins and vimentin, which are highly expressed by cells of the proximal tubule. 2–4 Although less than 100 cases have been reported in the English literature, the clinical data suggest that collecting duct carcinoma has the tendency to affect younger patients, present at more advanced stages and is associated with poorer prognosis. Most of the information on collecting duct carcinoma has focused on the histopathological characteriza- tion of the tumor, while clinical information has been spo- radically reported in case studies. We characterize the clini- cal features of 6 patients diagnosed with collecting duct carcinoma in the frame of the University of California School of Medicine, Los Angeles, Kidney Cancer Database. PATIENTS AND METHODS Between 1989 and 2000, 955 patients underwent nephrec- tomy for renal cell carcinoma at the University of California, Los Angeles. Of these patients 6 (0.6%) were diagnosed with collecting duct carcinoma. Demographic, clinical and patho- logical data were obtained from patient medical records. In- cidental diagnosis was defined as being completely asymp- tomatic at diagnosis or having symptoms that are attributable to a nonrenal cell carcinoma related disease. Baseline performance status with the criteria established by the Eastern Cooperative Oncology Group was assigned to each patient before surgery. Radiographic, operative and pa- thology reports were used to assess the extent of disease, including local involvement and distant metastasis at diag- nosis. Gross pathological examination included tumor size, location in the kidney and involvement of the caliceal system. Microscopic evaluation was done for determination of histo- logical type, Fuhrman’s nuclear grading and tumor stage. Cases were staged according to the International Union Against Cancer and American Joint Committee on Cancer 1997 TNM staging system. Patient survival was calculated from the date of nephrectomy to the last followup or death. RESULTS The occurrence of collecting duct carcinoma in our patient population was 0.6%. Table 1 shows the patient data. Mean patient age plus or minus standard deviation (SD) was 56  11 years (range 41 to 71) and male-to-female ratio 1:1. The left kidney was affected in 5 patients and the right 1. There Accepted for publication July 13, 2001. 0022-5347/02/1671-0071/0 THE JOURNAL OF UROLOGY ® Vol. 167, 71–74, January 2002 Copyright © 2002 by AMERICAN UROLOGICAL ASSOCIATION,INC. ® Printed in U.S.A. 71