Clear cell carcinoid tumor of the distal common bile duct

Background Carcinoid tumors rarely arise in the extrahepatic bile duct and can be difficult to distinguish from carcinoma. There are no reports of clear cell carcinoid (CCC) tumors in the distal bile duct (DBD) to the best of our knowledge. Herein, we report a CCC tumor in the DBD and review the literature concerning extrahepatic bile duct carcinoid tumors. Case presentation A 73-old man presented with fever and occult obstructive jaundice. Ultrasonography, computed tomography (CT) and magnetic resonance cholangiopancreaticography (MRCP) demonstrated a nodular tumor projection in the DBD without regional lymph node swelling. Under suspicion of carcinoma, we resected the head of the pancreas along with 2nd portion duodenectomy and a lymph node dissection. The surgical specimen showed a golden yellow polypoid tumor in the DBD (0.8 × 0.6 × 0.5 cm in size). The lesion was composed of clear polygonal cells arranged in nests and a trabecular pattern. The tumor invaded through the wall into the fibromuscular layer. Immunohistochemical stains showed that neoplastic cells were positive for neuron-specific enolase (NSE), chromogranin A, synaptophysin, and pancreatic polypeptide and negative for inhibin, keratin, CD56, serotonin, gastrin and somatostatin. The postoperative course was uneventful and he is living well without relapse 12 months after surgery. Conclusion Given the preoperative difficulty in differentiating carcinoid from carcinoma, the pancreaticoduodenectomy is an appropriate treatment choice for carcinoid tumors located within the intra-pancreatic bile duct.