Large bowel lymphoma
Large bowel (colorectal) lymphoma is a very rare tumor, accounting for <0.5% of primary colorectal malignancies, ~1.5% of all lymphomas, and ~15% of gastrointestinal lymphoma. Large bowel lymphoma differs from gastric and small bowel lymphoma in clinical presentation, management, and prognosis.
Epidemiology
Most commonly occurs in patients in their forties to sixties, with increasing incidence with age. There is a slight male predominance (M:F = 1.5:1) .
Clinical presentation
As with other colorectal tumors, primary symptoms are weight loss, pain and, less commonly, per rectal bleeding . Large bowel obstruction and perforation are rare.
Pathology
Diffuse large B-cell lymphoma is the most common subtype (~65%) of large bowel lymphoma. With other less common types including mucosa-associated lymphoid tissue (MALT) lymphoma and mantle cell lymphoma (MCL) .
The underlying etiology is unknown but an infective/inflammatory pathogenesis is suspected as there is higher incidence in patients with HIV/AIDS, inflammatory bowel disease, and post-transplantation immunosuppression .
The majority (~70%) of large bowel lymphomas occurs in the right colon .
Radiographic features
Compared to colorectal adenocarcinoma, lymphoma affects longer and multiple colonic segments , mostly characterized by circumferential wall thickening.