Anaplastic Large Cell Lymphoma of the Duodenum in a Teenage Girl: Misdiagnosed as an Intramural Duodenal Hematoma.

We report a case of a 13-year-old girl who presented with a 2-month history of intermittent abdominal pain. Laboratory examination showed hepatitis and pancreatitis. Because of persistent vomiting, computed tomography (CT) was performed, which revealed a circumferential soft tissue density in the duodenal wall, causing partial obstruction. Supportive therapy failed. Repeat CT showed no significant change from the initial study. The patient underwent upper endoscopy, which revealed a mass in the second portion of the duodenum, which occluded most parts of the lumen. The histopathological finding was consistent with an anaplastic large cell lymphoma, a rare form of small bowel neoplasm. After the third course of chemotherapy, complete resolution of the mass was noted, and her symptoms were relieved.