CASE REPORT: Plasmacytoid urothelial carcinoma of the urinary bladder: Two case reports

We report two cases of plasmacytoid urothelial carcinoma of the urinary bladder. The tumor in the first case presented as an irregular and erythematous urinary bladder lesion with pararectal or rectal tumor extension. Perineal, scrotal and intrabdominal metastases developed within 4 months despite neoadjuvant chemotherapy. A muscle-invasive urinary bladder tumor was seen in the second case with perivesical and perivesicular extension and regional lymph metastases at cystoprostatectomy. The tumor cells in both cases were nested or dyscohesive, and resembled plasma cells; focal signet ring cells were also seen in the second case. The advanced stage of both cases is consistent with the reported aggressive biologic course of most of these tumors. Awareness of this rare variant when dealing with urogenital tract carcinoma is important since the morphology may suggest another diagnosis. Because of peculiar expression of CD138, a plasma cell-associated marker, these tumors may be mistaken for a plasma cell-derived neoplasm.