Mixed Adenoneuroendocrine Carcinoma (MANEC) of the Gallbladder: A Systematic Review of Outcomes Following Surgical Management

Background/aim: Mixed adenoneuroendocrine carcinomas (MANEC) are uncommon tumors exhibiting both adenocarcinomatous and neuroendocrine differentiation. They most commonly arise in the colon, appendix, rectum or stomach, however, a limited number of MANECs have been reported to originate in the gallbladder (gMANEC). The aim of our systematic review was to accumulate the existing data on gMANEC with special attention to the clinicopathological characteristics, surgical approach, recurrence and survival rates of patients diagnosed with this rare malignancy.

Materials and methods: A comprehensive search of the literature was undertaken.

Results: A total of 15 studies (14 case reports and 1 case series), which comprised 19 patients who successfully underwent surgical treatment for gMANEC were included in our systematic review. During a median follow-up of 8 months (range=2-48 months) the overall survival was 87% and the recurrence rate was 21%.

Conclusion: Achievement of complete surgical resection is the mainstay of the therapeutic management. Additionally, the stage of the disease and the histopathological mapping of these tumors affect decision-making for adjuvant chemotherapy and seem to define the prognostic course of each patient.