Plasmacytoid Urothelial Carcinoma of the Bladder: Histological and Clinical Features of 5 Cases

Purpose: Urothelial carcinoma with plasmacytoid morphology is a rare and only recently described histological variant. To date only 22 cases have been published. We present clinical and histopathological features of 5 cases of plasmacytoid urothelial carcinoma at our institutions. Materials and Methods: From a consecutive series of 130 muscle invasive urothelial carcinoma cases 3 of plasmacytoid urothelial carcinoma (2.3%) were identified. Two additional plasmacytoid urothelial carcinoma cases, including I that was noninvasive, were also studied. Data were collected from clinical charts, histological review and followup. Results: Four patients had a muscle invasive tumor at first presentation. The nonmuscle invasive plasmacytoid urothelial carcinoma represents the second published case in the literature. Conventionally differentiated urothelial carcinoma was focally present in every case. Plasmacytoid urothelial carcinoma cells were dyshesive and showed abundant eosinophilic cytoplasm, leading to a plasmacytoid appearance. Positive staining for epithelial markers confirmed the epithelial nature of the tumor. All tumors showed negative E-cadherin expression. Adjuvant or neoadjuvant chemotherapy seemed to have a beneficial effect on survival in patients with advanced tumors since they experienced prolonged survival. Conclusions: Plasmacytoid urothelial carcinoma is a rare variant of urothelial carcinoma with defined clinical and pathological characteristics. Diagnostic pitfalls are missing hematuria and no grossly identifiable tumor despite muscle invasive tumor stage. Cases only show mucosal induration and thickened bladder walls. Our data raise the possibility that the loss of E-cadherin expression is a prerequisite for plasmacytoid urothelial carcinoma. Awareness of these aspects should lead to earlier diagnosis and improved long-time survival in patients with plasmacytoid urothelial carcinoma.