Inflammatory Myofibroblastic Tumor of the Distal Bile Duct Mimicking Cholangiocarcinoma: A Case Report

Inflammatory myofibroblastic tumor has been described in various locations. However, its appearance in the periampullary region is uncommon and has rarely been reported in the literature. We report a case of a 37-year-old Moroccan male with painless jaundice and pruritus. Endoscopic retrograde cholangiopancreatography and magnetic resonance cholangiopancreatography showed a 2-cm-long stricture in the distal bile duct that suggests a cholangiocarcinoma. There was no involvement of adjacent structures at computed tomography of abdomen. The patient underwent a pancreaticoduodenectomy. The tumor histology showed regular spindle cells arrayed in fascicles, admixed with lymphocytes, plasma cells and eosinophils. Immunohistochemical analysis showed positive staining for smooth muscle actin, H-caldesmon. In contrast, the tumor cells did not express cytokeratin, PS100, CD68, CD23, CD117 and ALK. Based on these data, the diagnosis of inflammatory myofibroblastic tumor of distal bile duct was made. We report this new case in the aim of shedding more light on this entity and the challenges in making the diagnosis in such location.