P0218 - A Rare Case of Helicobacter pylori Negative Primary MALT Lymphoma of the Rectum

Prabasha Weeraddana, MD, Mohammed Saleh, DO, Rella Vincent, MD
Danbury Hospital, Danbury, CT

Introduction: Extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) is a low-grade non-Hodgkin lymphoma. It typically arises from the stomach, adnexa, lungs, or salivary glands. Rectal MALT is rare and comprises 2.5% of MALT lymphomas.

Case Description/Methods: A 70 years old male past medical history of OSA presented to the gastroenterology clinic complaining of bright red blood per rectum. His last colonoscopy seven years ago showed sigmoid diverticulosis. The patient denied abdominal pain, no changes in bowel habits, weight loss, or loss of appetite. The patient underwent a colonoscopy for further evaluation and was found to have rectal polyps. Histology of polyps and biopsy from the anal verge revealed MALT lymphoma and was negative for H.pylori infection. CT chest/abdomen showed mild wall thickening of the upper rectum. PET scan showed greater radiotracer activity in the rectum and the right lower quadrant mesenteric lymph nodes. He was clinically observed; a follow-up PET scan in 1 year showed an interval increase in wall thickening of the rectum, also involving the distal sigmoid rectal junction. Repeated colonoscopy demonstrated large polypoid masses at the anal verge and rectum, which were positive for MALT lymphoma. But the patient was asymptomatic and continued to be clinically observed. After one year, the patient returned to the GI clinic, complaining of weight loss, constipation, early satiety, and bloating. Repeated endoscopy negative for H. pylori infection, colonoscopy again revealed nodular masses in the mid and distal rectal, which is similarly positive for MALT lymphoma. PET scan showed significant thickening and enlargement of the rectum with extensive pelvic, internal iliac, and inguinal adenopathy. As the patient was symptomatic patient was started on IV Rituxan 695 mg 4 cycles.

Discussion: MALT lymphomas have an indolent clinical course. The pathogenesis of colorectal lymphomas is not well understood. Rectal MALT can be asymptomatic or present with hematochezia, melena, prolapsed mass, or constipation. Systemic B symptoms are rare. There is no standardized therapy for rectal MALT, given its rarity. Colorectal MALT is treated with various modalities, including surgery, endoscopic resection, chemotherapy, radiation, or single agent rituximab. Our patient was clinically observed after endoscopic resection of rectal polyps. As follow-up images and colonoscopies showed a recurrence of the disease, he was started with Rituxan once the patient became symptomatic.



Disclosures:


Prabasha Weeraddana, MD, Mohammed Saleh, DO, Rella Vincent, MD. P0218 - A Rare Case of Helicobacter pylori Negative Primary MALT Lymphoma of the Rectum, ACG 2023 Annual Scientific Meeting Abstracts. Vancouver, BC, Canada: American College of Gastroenterology.