A case of urothelial carcinoma with triple variants featuring nested, plasmacytoid, and lipoid cell morphology

We present very rare variants of urothelial carcinoma featuring nested, plasmacytoid, and lipoid cell morphology in an 80-year-old female who was admitted to our hospital with mictritional pain and bilateral hydronephrosis. Abdominal computed tomography showed diffuse thickening of the urinary bladder, indicating probable invasion into the surrounding adipose tissue. Cytological tests on a urine specimen revealed medium-sized cancer cell clusters with hyperchromatic nuclei and dense cytoplasm, small clusters of dyshesive cells with eccentric or crescent nuclei, and abundant or vacuolated cytoplasm mimicking plasma cells or lipoblasts. Histopathological findings of the bladder tumor revealed that the nested urothelial carcinoma variants were mainly located in the lamina propria, whereas the plasmacytoid and lipoid-cell variants had deeply infiltrated into cells with a myxoid background. Immunohistochemically, the cancer cells were positive for cytokeratin, epithelial membrane antigen, but not for vimentin, S-100, or hematopoietic markers of plasma cells such as CD79alpha and CD38. The patient received no radiosurgical therapies because of the advanced stage of her disease and died a few months after the initial diagnosis. To our knowledge, this is the first cytological and histological examination of urothelial carcinoma consisting of nested, plasmacytoid, and lipoid-cell variants of the urinary bladder.