Tubulocystic carcinoma, mucinous tubular and spindle cell carcinoma, and other recently described rare renal tumors

In the recent past, the list of distinctive neoplasms that arise in the kidney has grown remarkably, aided by clinical and pathologic observation, and by the development of new ancillary diagnostic techniques. This article discusses several rare tumors. Two neoplasms (mixed epithelial and stromal tumors of kidney, and primitive neuroectodermal tumor of kidney) were identified 30 years ago, but have been studied extensively and characterized better recently. The other lesions that are discussed-mucinous tubular and spindle cell carcinoma, tubulocystic carcinoma, epithelioid angiomyolipoma, and primary renal synovial sarcoma-have been described only in the past 10 to 15 years, and delineation of their characteristics continues.