Urothelial Carcinoma of the Bladder, Lipid Cell Variant: Case Report and Literature Review.

The lipid cell variant of urethral carcinoma (UC) is rare and poorly understood clinicopathologically. A nodular tumor detected in the bladder of an 87-year-old man with asymptomatic gross hematuria was transurethrally resected, and high-grade UC, lipid cell variant, was diagnosed pathologically. The tumor cells resembled lipoblasts and contained numerous cytoplasmic vacuoles. Immunohistochemically, the tumor cells stained positive for the epithelial markers CK7, CK20, EMA, CAM5.2, and 34betaE12 and negative for vimentin and S100. Focal positivity for adipophilin was detected in cytoplasm but not in the vacuoles. These findings suggest that the patient had lipid-producing UC.