Neuroendocrine neoplasms of the gallbladder: A case series and clinicopathological insights from a tertiary care hospital in Northeast India

Abstract

Gallbladder neuroendocrine neoplasms (GB-NENs) are extremely rare, forming about 0.5% of all neuroendocrine tumors (NETs) and roughly 2% of gallbladder malignancies. Their clinical presentation is often vague and mimics common conditions such as gallstones or adenocarcinoma, which makes diagnosis difficult before surgery. This retrospective review was conducted at a tertiary care hospital in Assam, India, covering cholecystectomy specimens from January 2014 to December 2023. Out of 6,532 specimens examined, 191 were cases of gallbladder carcinoma, and only 3 (1.57%) were identified as GB-NENs through histopathology and immunohistochemistry (IHC). Clinical details, pathological findings, treatment, and outcomes of these patients were studied. All three patients were women, with a mean age of 49 years. Abdominal pain was the most common presenting symptom. The first case was an incidental finding of a NET Grade I following cholecystectomy for cholelithiasis. The second case presented with jaundice and was diagnosed as a Well-Differentiated NET Grade III showing lymphovascular invasion and nodal metastasis; she underwent surgery followed by chemotherapy. The third case was a poorly differentiated neuroendocrine carcinoma involving the gallbladder neck and peritoneum with extensive lymphadenopathy; she later developed cervical lymph node metastasis within 11 months and is currently on chemotherapy. Gallbladder tumors occasionally include this rare but clinically important subtype. Because the symptoms and imaging findings are non-specific, diagnosis is usually made only after surgery, with histopathology and IHC remaining the definitive tools. Poorly differentiated forms tend to metastasize early and carry a poor prognosis, though surgery continues to be the most effective treatment option. Greater clinical awareness, a multidisciplinary approach, and further studies on targeted therapies are vital for improving outcomes in GB-NENs.