An autopsy case of primary extranodal NK/T cell lymphoma (extranodal NK/T-cell lymphoma) of the bile duct.

We reported the case of a 50-year-old man diagnosed with extrinsic NK/T-cell lymphoma. He was initially diagnosed with locally advanced unresected pancreatic duct carcinoma and was treated with combination chemotherapy using gemcitabine and nabpaclitaxel. One month after treatment, he developed bleeding. Upper gastrointestinal endoscopy showed a deep ulcer lesion from the duodenal bulb to the inner wall of the descending section that was not observed before treatment. Coil embolization was performed, but the necrotic area widened after treatment; the patient died of disseminated intravascular coagulation after 1 week. Autopsy showed a soft white-tone lesion that extended from the ulcer wall to the gallbladder wall and around the intrahepatic bile duct. Lesions were also found in the spleen, lungs, kidney, and bone marrow, and immunohistochemistry confirmed extrinsic NK/T-cell lymphoma (extranodal NK/T-cell lymphoma, nasal type). In conclusion, histological diagnosis of NK/T-cell lymphoma is difficult at an early stage, and the clinical course often shows rapid tumor progression, particularly bleeding in the digestive organs or widespread perforation and penetration. NK/T-cell lymphoma should be ruled out in patients with bile duct and pancreatic tumors in whom tissue diagnosis via biopsy cannot be performed.