In this report, we summarized the clinicopathologic features of 9 cases of plasmacytoid transitional cell carcinoma (TCC) of the urinary bladder, a rare variant of TCC. All 9 patients were men with a mean of age 64.3 years (range, 46 to 81 y). All but 1 patient presented with gross hematuria; the remaining patient had urgency and microscopic hematuria. Cystoscopic findings revealed a dominant solid mass with surrounding multiple papillary lesions in 6 cases and multiple masslike lesions in 3 other cases. The initial diagnosis of plasmacytoid TCC was made on transurethral resection in 8 cases and cystoscopic biopsy in 1. One patient had TNM stage I disease, 2 had stage II disease, 3 had stage III disease, and 3 had stage IV disease. Four patients were treated by radical cystectomy with chemotherapy, 2 by radical cystectomy alone, 1 each by chemotherapy or intravesical bacillus Calmette-Guerin infusion alone, and 1 did not receive any further therapy. Microscopically, all tumors contained plasmacytoid cells, which composed 30% to 100% of the entire tumor. Eight of 9 cases were associated with high-grade TCC, and transitional cell carcinoma in situ was present in 4 cases. The plasmacytoid tumor cells were characterized by eccentrically located nuclei and abundant eosinophilic cytoplasm. Interestingly, plasmacytoid transitional cell carcinoma in situ was noted in 1 case. Immunohistochemical staining demonstrated that both plasmacytoid and conventional TCC components were positive for cytokeratins 7 and 20. The mean Ki-67 labeling index was 30% (range, 10% to 50%), and p53 expression in the majority of cases was low (5% to 10%), except for in 2 cases (70% and 80%). The mean follow-up in 8 patients was 24.5 months (range, 5 to 47 mo); the other patient was lost to follow-up. Five patients died of disease from 5 to 36 months, 2 patients were alive with disease at 30 and 47 months, and 1 patient was alive and well at 36 months with no evidence of disease. In summary, plasmacytoid TCC tends to present at an advanced stage and to have a poor prognosis. Morphologic recognition and distinction from other plasmacytoid malignant neoplasms is critical for its clinical management and immunohistochemical studies may be required for differential diagnosis.