Endoscopic features of colorectal lymphoma according to histological type.

Background and Aim: This study aimed to investigate the relationship between the histological type of colorectal lymphoma and its endoscopic features. Methods: We retrospectively analyzed patients with primary colorectal lymphoma who were diagnosed using colonoscopy and biopsy specimens at the National Cancer Center Hospital, Tokyo, Japan. The lesions were macroscopically classified into the following types via colonoscopy: polypoid, ulcerative, multiple lymphomatous polyposis, diffuse, and mixed. Results: A total of 117 lesions were identified in 90 patients enrolled in this study. Of these, 59 (50%) were located in the ileocecal region, 23 (20%) in the rectum, 9 (8%) in the transverse colon, 8 (7%) in the sigmoid colon, 7 (6%) in the descending colon, and 4 (3%) in the ascending colon. Moreover, the most common histological subtypes were diffuse large B-cell lymphoma (DLBCL) in 39 patients (43%) and mantle cell lymphoma (MCL) in 23 patients (26%), followed by follicular lymphoma (FL; 17%), mucosa-associated lymphoid tissue (MALT) lymphoma (9%), peripheral T-cell lymphoma-NOS (2%), monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL; 2%), and Burkitt lymphoma (1%). More than half of the DLBCL (52%), MCL (52%), and MALT (56%) lymphomas were macroscopically classified as polypoid types. In contrast, FL lesions showed various macroscopic types. The majority of DLBCL (62%) and FL (78%) lesions were distributed in the ileocecal region. MCL lesions tended to be widely spread in various sites of the large intestine. Conclusions: Colorectal lymphomas showed macroscopically distinctive features depending on the histological type. Understanding the macroscopic classification of the lesions by colonoscopy and its distribution may be helpful in diagnosing the type of lymphoma and determining the malignant grade based on the histological types.