Small Cell Carcinoma of Gallbladder With Nodal Metastasis Mimicking As Synchronous Malignancy in Gallbladder and Common Bile Duct.

Small cell carcinoma of the gallbladder is an extremely rare disease. Even with current aggressive and diverse treatments, small cell carcinoma of the gallbladder has an extremely poor prognosis. The presence of synchronous malignancies in the gallbladder and the biliary tract is even rare. Synchronous malignancy can be due to either local spread or metastasis. It can also occur due to field change in the extrahepatic malignancy or can arise de novo as multifocal malignancy. Small cell carcinoma of gallbladder with nodal metastasis mimicking as synchronous malignancy in the gallbladder and distal common bile duct is rare. We report a 74-year-old male who presented with abdominal pain and jaundice. Initial imaging studies were suggestive of the possibility of synchronous malignancy in the gallbladder and common bile duct. However, further imaging studies showed that carcinoma of the gallbladder had metastasis to the lymph nodes, causing external compression to the common bile duct rather than synchronous malignancy. Cytology was diagnostic of small cell carcinoma of the gallbladder. The patient had metastasis to other sites also. The patient underwent endoscopic retrograde cholangiopancreatography with stenting and started on palliative platinum-based chemotherapy with cisplatin and gemcitabine, and he is under regular follow-up.