A rare case of diffuse large B-cell lymphoma presenting as a malignant mass in both duodenum and ascending colon.

Lymphoma in the gastrointestinal tract most commonly occurs in the stomach, small intestine and around the ileocecal region. Usually gastrointestinal lymphoma occurs secondary to widespread nodal disease and is rarely found to be the primary site. Of the different types of lymphoma, diffuse large B-cell non-Hodgkin's lymphoma makes up the majority of lymphomas in the gastrointestinal tract. Primary colorectal lymphoma is even less common and accounts for 3% of all gastrointestinal lymphomas and to our knowledge, gastrointestinal lymphoma involving 2 different regions in the GI tract has not been discussed in the literature. Herein, we are presenting a rare case of diffuse large B-cell lymphoma presenting as a malignant mass in both the duodenum and ascending colon.