Abstract
A 67-year-old woman complaining of jaundice was found to have obstruction of the inferior bile duct by magnetic resonance cholangiopancreatography at a neighboring hospital, and was referred to the department of gastroenterological medicine in our hospital. Abdominal CT scan revealed a 20-mm diameter tumor at the inferior bile duct at where the bile duct had obstructed. A swollen lymph node was present at the dorsal aspect of the pancreas head. Endoscopic retrograde cholangiopancreatography showed a well-defined tumor with a heterogeneous center part which had protruded into the bile duct. Positron emission tomography showed abnormal uptake of FDG, SUVmax=5.6, at the inferior bile duct tumor and a slight uptake at the lymph node which was indicated by CT. Subtotal stomach-preserving pancreatoduodenectomy was performed with the diagnosis of inferior bile duct carcinoma, when we identified a white tumor at the pancreas head and its upstream bile duct from the tumor to have dilated significantly. Furthermore metastasis to the #13 lymph node was identified. Histology showed tumor cells arranged from honeycomb to sheet-like pattern and infiltration of the tumor cells into the surrounding tissues. Based on MIB-1 index and mitotic figure as well as immunohistochemistry, we diagnosed the case as neuroendocrine tumor of the bile duct, which corresponds to NET G2 in accordance with the 2010's WHO Classification.
