Primary lymphoma of the terminal ileum. The differential for a mass in this location is lymphoma, adenocarcinoma, GIST, and carcinoid tumor. Lymphoma can be slightly favored due the bland, soft-tissue appearance of the mass and lack of adenopathy that would be expected in the setting of adenocarcinoma this size.

It is helpful to at least suggest lymphoma as this patient might be treated with systemic therapy (rather than hemicolectomy) in the absence of obstruction. This patient underwent right hemicolectomy due to symptoms related to intussusception.