Mixed adenoneuroendocrine carcinoma of the gallbladder: a case report and review of the literature.

Neuroendocrine carcinoma (NEC) is a rare malignant tumor of the gallbladder (GB) and is extremely rare in medical practice. Related case reports and in-depth studies are extremely limited, resulting in an insufficient understanding of the disease. This article reports a case of a 60-year-old female patient who complained of right upper abdominal pain for 20 days. Subsequent examinations confirmed that it was mixed adenoneuroendocrine carcinoma of the gallbladder (GB-MANEC), of which the neuroendocrine part accounted for approximately 70%, and was defined as a poorly differentiated NEC. The Ki-67 index reached 80%, indicating highly aggressive behavior. Postoperative adjuvant chemotherapy was administered (six cycles of etoposide combined with cisplatin). Follow-up through December 2024 showed no signs of tumor recurrence, with a disease-free survival period of 12 months. Currently, the preferred treatment strategy for GB-NEC is radical surgery. Therefore, in this case, radical resection combined with chemotherapy became an effective treatment.