*3.10. Eosinophilic (Oncocytoid) Cells*

An eosinophilic change can be observed in some UC resembling the cells of renal oncocytomas [82]. These cases show large granular and deeply eosinophilic elements with focal apocrinoid features (Figure 2h). Frequent nuclear pleomorphism is also seen, but true atypia is lacking. Mitoses are scarce, or absent, giving an overall impression of a low-grade tumor. Immunohistochemistry is that of the conventional UC, and neuroendocrine markers are negative. Anyway, further descriptions are needed to delineate better this histologic feature. At least for practical purposes, this histologic feature should be distinguished from oncocytic carcinoid tumors of the urinary bladder [83], an extraordinarily rare entity in the urinary bladder.
