A Case of Malignant Lymphoma of the Ileocecum which was Difficult to Differentiate from an Ileocolic Arterial Aneurysm Rupture

An 81-year-old man visited our hospital complaining of abdominal pain. An enhanced CT scan revealed a suspected 3-cm-large aneurysm with contrast enhancement in the early phase in the right mesentery. Transcatheter arterial emboliza-tion was performed and the patient was discharged after follow-up. Six months later, the patient visited the emergency room due to abdominal pain, and enhanced CT revealed a 5-cm-large mass with partial contrast effect in the right mesentery. Suspecting re-rupture of the aneurysm, an ileocecal resection was performed. Operative findings revealed a tumor in the right mesentery, so the tumor was resected. Pathological examination revealed that the tumor was mesenteric malignant lymphoma. We report this case of malignant lymphoma mimicking a ruptured ileocolonic aneurysm.