Primary neuroendocrine carcinoma of gallbladder is extremely rare, representing 0.2% of all neuroendocrine tumors, as normal gallbladder mucosa does not contain neuroendocrine cells. Little is known about its biological behavior. Diagnosis is incidental in most of the cases. We sought to give an overview of the current state of knowledge about gallbladder neuroendocrine tumors. We describe the case of a 55‑year‑old man who underwent cholecystectomy for the evaluation of a gallbladder mass that had been incidentally detected by ultrasonography. Histologically, the lesion was composed of monomorphic cells that contained round nuclei and were organized in small nests, nodules, trabeculae, and acini. Cells were positive for chromogranin A and a diagnosis of neuroendocrine carcinoma of the gallbladder was made. He is disease‑free 8 months after surgical treatment. Characteristic pathological findings of the gallbladder neuroendocrine tumors predict the prognosis. Given the difficulty in distinguishing between benign and malignant lesions in the pre‑surgical setting, we tend to emphasize the need for cholecystectomy in all cases, relying on the pathological and immunohistochemistry analyses for the final diagnosis. The biological behavior of the tumor is still not well defined. Thus, reporting every case is important and may contribute to the existing knowledge regarding the behavior and management of this rare tumor.