Large cell neuroendocrine carcinoma of the urinary bladder with lymphoepithelioma-like features.

The group of undifferentiated carcinomas of the urinary bladder encompasses small cell undifferentiated carcinoma, giant cell carcinoma, lymphoepithelioma-like carcinoma (LELC), and large cell neuroendocrine carcinoma (LCNEC). These tumors are either pure or can be associated with other components, such as transitional cell carcinoma, squamous cell carcinoma, and adenocarcinoma. We report a case of LCNEC of the urinary bladder in a 54-year-old woman. Histologically, the tumor showed features of LELC; immunohistochemically, the tumor cells reacted to chromogranin A, NSE, and synaptophysin. In addition to these neuroendocrine markers, tumor cells were positive for cytokeratin CAM 5.2 and AE1/AE3, and there was focal positivity for vimentin. In situ hybridization for the detection of Epstein-Barr virus was negative. Despite radical cystourethrectomy and six courses of chemotherapy, the patient developed metastases invading the left inguinal lymph nodes 11 months postoperatively. Currently, 16 months postoperatively, the patient has developed metastases spreading into the lymph nodes of the right ischiorectal fossa; therefore, she is receiving a new cyclus of chemotherapy. There are only three previously reported cases of LCNEC of the urinary bladder, and the significance of neuroendocrine differentiation in non-small cell carcinomas at this location remains to be established. However, LELC appears to be a separate clinicopathological entity with sensitivity to chemotherapy and a relatively favorable prognosis. The differentiation between LELC and LCNEC with prominent inflammatory reaction could be of therapeutic relevance. However, in our case, this was possible using immunohistochemistry only.