OBJECTIVETo study the clinicopathologic features and prognosis of plasmacytoid urothelial carcinoma (PUC) of the urinary bladder.

METHODSThe clinical and pathologic findings of 16 cases of PUC were retrospectively reviewed. Immunohistochemical study (MaxVision method) was carried out. The follow-up data were analyzed.

RESULTSThere were altogether 15 males and 1 female. The age of patients ranged from 40 years to 85 years (median = 64 years). Most patients (15/16) presented with hematuria. The tumor cells were small to medium in size and contained eccentric nuclei and moderate to abundant eosinophilic cytoplasm, assuming a plasmacytoid appearance. The architectural pattern varied from loosely cohesive sheets to cords, papillae, small nests or gland-like structures. Most tumors invaded into the lamina propria or muscularis propria. Twelve of the 16 cases had concurrent conventional urothelial carcinoma component. Immunohistochemical study showed that the tumor cells in all cases were strongly positive for AE1/AE3, epithelial membrane antigen, CK7 and CK18. CK20 and uroplakin III were also expressed in 9 cases. CEA, p53, CD138, p63 and E-cadherin were positive in 12, 13, 15, 11 and 10 cases, respectively. Ki-67 index ranged from 5% to 70% (mean = 30%). All tumors were negative for vimentin, LCA, kappa/lambda light chains, S-100 protein, HMB 45,Melan A, smooth muscle actin and desmin. Follow-up information was available in 13 patients. The duration of follow up ranged from 3 months to 10 years. Three patients died of distant metastasis at 3, 27 and 60 months after the operation, respectively. One patient was alive with disease at 25 months. One was alive at 43 months with a prior recurrence. Another 8 patients were alive and disease free at 7 to 120 months.

CONCLUSIONSPUC of the urinary bladder is a rare variant of high-grade urothelial carcinoma. Immunohistochemical study with positivity for CK7, CK20, p63 and uroplakin III and negative staining for vimentin and LCA may be helpful in the differential diagnosis. PUC is a malignant tumor with high invasiveness, high recurrence rate and poor prognosis. Radical cystectomy is considered as the first line treatment for PUC.