Applications of Immunohistochemistry: E-cadherin, CK7, CK20, CD38, CD56 and Ki-67 in Distinguishing Plasmacytoid Urothelial Carcinoma from Small Cell Neuroendocrine Carcinoma

Bladder cancer has a propensity for divergent differentiation with different prognosis. Urothelial carcinomas are the most frequent and important tumour type. In this study, immunhistochemical method was employed to detect the expression of E-cadherin, CK7, CK20, CD138, CD38, CD56 and Ki-67 in 7 cases of high grade aggressive bladder carcinoma. Our study shown 2 cases plasmacytoid urothelial carcinoma (PUC) positive for CD38 and CD138, and lost the membranous expression of E-cadherin. Five cases small cell neuroendocrine carcinoma present CD56 strong positive and Chr A, Syn, NSE neuroendocrine carcinoma marker from weekly positive to stronger. The seven cases were negative for several lymphoid markers, embryonal rhabdomyosarcoma markers and malignant melanoma markers. The expression of Ki-67 was approximately 20% to 60%. Applications of immunohistochemistry of E-cadherin, CK7, CK20, CD38, CD56 and Ki-67 can distinguishing small cell high grade urothelial carcinoma. PUC and small cell neuroendocrine carcinoma are uncommon and aggressive variant of bladder carcinoma associated with late presentation and poor prognosis. The correct diagnosis of them may be reached by combination of immunohistochemical E-cadherin, CK7, CK20, CD38 and CD56 results, its typical histological features and clinic characteristics.