Primary Diffuse Large B-Cell Lymphoma of the Descending Colon.

Primary non-Hodgkin lymphoma of the gastrointestinal tract is rare with an incidence of 10-15% of all non-Hodgkin lymphoma cases and 1-4% of all gastrointestinal tumors. The most common sites of involvement include the stomach, small intestines, colon and rectum. Primary colorectal lymphoma is extremely rare representing only 0.2-0.6% of all colorectal malignancies. The presentation is usually non-specific leading to delay in diagnosis. Imaging is used to locate the tumor and its extension. Colonoscopy usually shows a fungating mass, infiltrative or ulcerative lesion. Diffuse large B-cell lymphoma is the most common histological subtype. Management of diffuse large B-cell lymphoma usually involves chemotherapy, radiation, surgery or a combination approach.