Eosinophilic Solid and Cystic Renal Cell Carcinoma (ESC RCC): Clinicopathologic Study of a Series of 4 Patients from Brazil With Report of Cell Cannibalism as a Novel Microscopic Finding.

We report the clinicopathological findings of the first series of 4 patients from Brazil with eosinophilic solid and cystic renal cell carcinoma (ESC RCC). In our study, there were 3 female patients and 1 male patient. The youngest female patient had bilateral tumors and a past history of tuberous sclerosis. The morphologic findings were in accordance with the literature. Macroscopically, the tumors were nonencapsulated disclosing solid, macrocystic and/or microcystic arrangement. In the largest tumor the arrangement was purely solid with frequent and extensive necrosis. The characteristic and distinctive morphologic feature of the tumors was the "stippling." The tumoral cells disclosed abundant eosinophilic cytoplasm, containing characteristically thin or coarse basophilic or purple granules. Not rarely, the granules were surrounded by a clear halo imparting a "leishmania-like" aspect which is an additional frequent feature of ESC RCC. A novel morphologic finding of ESC RCC in our series was the presence of "cell cannibalism" in the largest tumor and with extensive necrosis. "Cell cannibalism" may be associated with aggressiveness of the tumor cells. All 4 patients are alive and without tumor progression, but the follow-up of our series was short.