CD138-positive plasmacytoid urothelial carcinoma of urinary bladder with focal micropapillary features.

Both the plasmacytoid and micropapillary types of urothelial carcinoma of the urinary bladder are uncommon, distinct clinical and pathological findings. To date, several reports in the English medical literature have been published on either of these variants. CD138 is commonly used as a marker for tumors of plasma cell origin. However, few authors have described positive immunoreactivity of plasmacytoid cells in urothelial carcinoma. Mixed histological differentiation is thought to be a phenotype of locally aggressive and advanced urothelial carcinoma. Therefore, a precise histopathological diagnosis should be made and awareness of all the entities is crucial. We report a case of CD138-positive plasmacytoid urothelial carcinoma of the bladder with focal micropapillary features. To our knowledge this is the first case of these two rare subtypes of urothelial carcinoma combined in a single cystectomy specimen.