Colorectal lymphoma

Lymphoma of the colon and rectum is a rare clinical entity that comprises only 0.2% of large intestinal malignancies. The gastrointestinal tract is the most common site of extranodal lymphoma involvement. Among colorectal lymphoma, over 70% are found proximal to the hepatic flexure. The most common presenting symptoms are abdominal pain and weight loss, which are non-specific findings. Lower GI bleeding and perforation are rare. Diffuse large B-cell lymphoma is the most common histologic subtype followed by mucosa-associated lymphoid tissue (MALT) lymphoma. In clinical practice, the modified Ann Arbor staging system is most widely utilized means for staging. Radiographic findings associated with colorectal lymphoma are non-specific and mimic those found with colorectal adenocarcinoma and inflammatory bowel disease. Tissue biopsy in the non-urgent setting can be obtained by colonoscopy. Surgical resection remains the definitive treatment for colorectal lymphoma with the majority of patients receiving post-operative chemotherapy with cyclophosphamide, vincristine, doxorubicin, and prednisone (CHOP), with or without the addition of Rituximab (R-CHOP). Median survival ranges between 24 and 36 months with 5-year survival rates of 25–55%.