Urothelial Carcinoma - Plasmacytoid Variant
This high-grade variant of urothelial carcinoma consists of single tumor cells with plasmacytoid features infiltrating loose myxoid stroma. The surface shows partially denuded conventional high-grade urothelial carcinoma. This variant may be mistaken for lymphoma, plasmacytoma, metastatic carcinoma, melanoma, or even chronic cystitis. Immunostains such as cytokeratin, lymphoid markers, and S-100 may be useful, especially in small biopsies.