Two cases of neuroendocrine carcinoma of the gallbladder.

Neuroendocrine carcinoma (NEC) of the gallbladder is a rare subtype of gallbladder tumor. Here, we report two cases of NEC in two patients initially suspected to have gallbladder carcinoma. No specific symptoms or abnormal blood test results were observed preoperatively. Abdominal computed tomography scans indicated intraluminal masses in the gallbladder and lymph node enlargement in the hepatic hilum. Radical cholecystectomy and regional lymphadenectomy were performed. The first patient also presented with liver invasion and therefore underwent resection of liver segment IV. A diagnosis of NEC was made upon postoperative pathological examination and immunohistochemical staining according to the WHO Classification of Tumors of the Digestive System (2010). One tumor was identified as poorly differentiated NEC and the other as poorly differentiated mixed adenoneuroendocrine carcinoma. Immunohistochemical staining data from both tumors showed positivity for chromogranin A and synaptophysin. The first patient received 4 cycles of chemotherapy consisting of cisplatin and etoposide. No metastases or recurrence were observed 12 mo following surgery. The second patient refused chemotherapy and presented with tumor recurrence 4 mo after surgery. In conclusion, NEC of the gallbladder is an aggressive tumor and the identification of a standardized optimal treatment still requires further research. Our experience together with published studies suggests that radical surgery and adjuvant chemotherapy may improve the prognosis.