Management of Renal Collecting Duct Carcinoma

Collecting duct carcinoma (cdc) or Bellini duct carcinoma is a rare type of renal cell carcinoma (rcc) thought to originate from renal collecting duct epithelium. Three multi-institutional retrospective cdc series including 262 patients were recently published from the United States1, Europe2, and Japan3. The U.S. population–based series by Wright et al. characterized cdc epidemiology in North America (Table i)1. Compared with clear cell rcc, cdc is more common in African American and male patients. The median age at diagnosis of 63 years did not differ from that for clear cell rcc. At diagnosis, collecting duct carcinoma was also more commonly locally advanced, metastatic, and poorly differentiated, resulting in worse 1and 3-year disease-specific survivals. The European2 and Japanese3 series also found that cdc presents at an advanced stage and has a poor prognosis. Additionally, those series indicated that more than two thirds of patients with cdc exhibit locoregional or systemic symptoms on presentation. The most common metastatic sites included regional lymph nodes, lung, bone, and liver3. Two retrospective series with a total of 35 patients suggest that several computed tomography findings may predict cdc histology4,5. Those findings include medullary location, weak and heterogeneous enhancement, involvement of the renal sinus, infiltrative growth, preserved renal contour, and a cystic component. Nonetheless, the low pre-test probability of cdc and the lack of specificity in the criteria necessitate histopathology for cdc diagnosis. The major criteria for cdc classification in the World Health Organization’s Classification of Tumors include location in a medullary pyramid; ABSTRACT