Risk-stratified clinical management of primary colorectal mucosa-associated lymphoid tissue lymphoma based on endoscopic morphology.

PURPOSE: Primary colorectal mucosa-associated lymphoid tissue (MALT) lymphoma is a rare and indolent disease with no standardized treatment. Lacking clear risk stratification criteria, treatment strategies vary widely from observation to systemic therapy. This study aimed to identify predictors of advanced-stage disease to propose risk-stratified treatment.

METHODS

Patients diagnosed with primary colorectal MALT lymphoma at Samsung Medical Center (Seoul, Korea) between January 2016 and October 2025 were enrolled. Clinical, laboratory and endoscopic features were analyzed. The primary outcome was to identify risk factors for advanced stage and disease progression.

RESULTS

Among 36 patients (median age 56 years; 58.3% male), 22.2% presented with advanced-stage disease. Mass-forming type (n = 6) was strongly associated with advanced stage compared with other morphologies (83.3% vs. 10.0%; OR 45.0, 95% CI 3.86-524.7; p < 0.001), whereas the single-polypoid type (n = 13) was observed only in localized disease (Lugano stage I; p = 0.032). Additional risk factors for advanced stage were involvement of multiple segments (OR 13.89, p = 0.006) and lesion multiplicity within a single segment of the colon (OR 7.50, p = 0.036). During a median follow-up of 35 months, no deaths occurred, and disease progression was rare (n = 2) with no progression observed after endoscopic resection.

CONCLUSION

Endoscopic morphology strongly predicts disease stage in colorectal MALT lymphoma. Mass-forming lesions and multiplicity suggest high-risk disease requiring systemic therapy, whereas single-polypoid lesions represent low-risk disease suitable for endoscopic resection.