Tubulocystic carcinoma of the kidney

Abstract

Examples of tubulocystic carcinoma of the kidney were introduced in an abstract presented at the Annual Meeting of the United States and Canada Academy of Pathology1 and also in the Armed Forces Institute of Pathology Atlas of Tumor Pathology, Series III, in 1994.2 However, the morphological features of this rare distinctive renal tumor were described in 1955 byMasson, who designated the lesion a “Bellinian epithelioma” because he regarded it as a neoplasm originating in the collecting ducts of Bellini. The first detailed report of the clinical and pathological details of tubulocystic carcinoma were published in 1997.3 The authors described the neoplasm as a “low-grade mucinous tubulocystic renal carcinoma of possible collecting duct origin”. The cases were initially considered to be derived from the collecting duct; however, since those reported tumors were of a low-grade malignancy, the behavior of which significantly differed from the classical highly aggressive collecting duct carcinomas, the term “low-grade collecting duct carcinoma” was coined for this peculiar renal tumor. Thereafter, with more cases showing similar clinical and pathological features, the name of the neoplasm was designated “tubulocystic carcinoma” to denote the specific morphology.4e8 To date, more than 50 cases have been reported. A review of the literature showed a male predominance (of around 7:1) with patient ages ranging from 34 years to 74 years. Tumor sizes range from 0.3 cm to 17 cm, but most are small and discovered incidentally. Tumors tend to present in a low stage (pT1a) and behave indolently. However, sarcomatoid change,9 and metastases to lymph nodes, lungs, and brain were reported.7