Primary Neuroendocrine Tumor in Type-1C Choledochal Cyst

Abstract

Cholangiocarcinoma is the most common biliary tumor and a dreaded complication of choledochal cyst. However, the development of neuroendocrine tumor (NET) in choledochal cyst is very rare due to the paucity of Kulchitsky cells. Here, we are presenting a case report on primary NET in choledochal cyst. To date, only four case reports have been published globally and all of them were diagnosed postsurgically; this is the first case diagnosed prior. A 45-year-old female presented with abdominal pain. Imaging showed dilated common hepatic duct and proximal common bile duct with soft-tissue mass lesion in the lateral wall, infiltrating the liver with liver metastasis (suspected as cholangiocarcinoma). As the patient was inoperable, palliative care was planned. To have tissue diagnosis, we proceeded with endoscopic retrograde cholangiopancreatography and brush cytology, but no malignant cells were detected. Image-guided biopsy was done, and surprisingly, the report came to be NET. To rule out occult metastasis elsewhere, positron emission tomography–computed tomography (DOTANOC) scan was done, which was suggestive of a primary bile duct growth with multiple liver metastases. Because of slow growth, nonfunctional nature, and clinical and radiological resemblance with cholangiocarcinoma, biliary tract NETs are very difficult to diagnose preoperatively.