P1249 - MALT Lymphoma of the Colon: A Case Series of a Rare Disease

Usman S. Ansari, DO, Shaadi J. Abughazaleh, MD, Mary R. Schwartz, MD, Gulchin A. Ergun, MD
Houston Methodist Hospital, Houston, TX

Introduction: Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is an uncommon malignancy that comprises ~ 5% of all non-Hodgkin lymphomas (NHL). Prevalence of colonic MALT lymphoma (MALToma) is < 2.5% of all MALTomas. Since rare, little is known about clinical features, endoscopic findings, treatment or prognosis.

Case Description/Methods: A retrospective review of the Pathology database at our institution identified five patients diagnosed with colorectal MALToma by colonoscopy. Average age was 60.2 years, range 39-78. The M:F ratio was roughly 1:1. Four asymptomatic patients were diagnosed at screening colonoscopy and found to have low grade MALTomas; one underwent endoscopy for diarrhea, weight loss, and iron deficiency anemia (IDA) and a MALToma with focal transformation to high grade diffuse large B-cell lymphoma was found. Majority of polyps (3, 60%) were sessile, one was a mucosal excrescence and the fifth was semi-pedunculated. Average size was small, 6.3 mm, and all in the right colon.

Patient 1 (P1) was asymptomatic but had concurrent gastric MALToma with + H. pylori and remission after eradication. P2 had a h/o basal cell carcinoma with diffuse colonic spread of MALToma after two years. P3 had h/o lung adenocarcinoma and stable MALToma with persistent right-sided disease off therapy. P4 had h/o IDA and Barrett’s esophagus and was lost to follow-up after diagnosis. P5 had h/o NHL with family h/o colon cancer. He was hospitalized for diarrhea, weight loss and IDA, treated with IV dexamethasone with symptom resolution, but lost to follow-up. P2 and P3 remained asymptomatic and monitored off treatment.

Discussion: MALToma of the colon primarily affects asymptomatic middle-age to older adults with no gender bias and often found on screening colonoscopy. Endoscopic appearance is benign with small sessile polyps without bleeding or erosions, predominantly in the right colon. Histology was classified as low grade in four patients with focal transformation to high grade DLBCL in one. Comorbid nonmetastatic cancer was observed in 80% patients. Treatments were not standardized but included H. pylori eradication and steroids with two patients monitored off therapy. One was lost to follow-up untreated.

Our series highlights that a rare diagnosis of colorectal MALToma can be made on biopsy of small benign appearing polyps in asymptomatic patients stressing the vital role of endoscopy in identifying this disease.




Disclosures:


Usman S. Ansari, DO, Shaadi J. Abughazaleh, MD, Mary R. Schwartz, MD, Gulchin A. Ergun, MD. P1249 - MALT Lymphoma of the Colon: A Case Series of a Rare Disease, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.