Granular cell tumor of distal bile duct treated with Whipple's procedure.

Granular cell tumors (GCTs) are rare benign neoplasms that are most often located in the soft tissues of the extremities and chest wall. Malignant GCTs have also been reported. GCTs of the biliary tract are extremely rare, uncommon non-epithelial benign neoplasms that cause focal thickening of bile duct wall without mucosal invasion.