Successful treatment of an enormous rectal mucosa-associated lymphoid tissue lymphoma by endoscopic full-thickness resection: A case report.

Background: Colorectal mucosa-associated lymphoid tissue lymphoma (MALToma), a rare kind of nongastric MALToma, lacks consensus on its endoscopic features and standard therapies. According to previous studies on the clinical characteristics and outcomes of colorectal MALToma, endoscopic resection remains a good therapeutic strategy.

Case Summary: A 71-year-old woman suffered intermittent hematochezia for 1 mo, accompanied with abdominal pains but without weight loss, fever, chills or fatigue. Colonoscopy showed a massive hemispheric mass with rough and hyperemic mucosa in the lower rectum. Narrow-band imaging magnifying endoscopy detected some branching abnormal blood vessels and disappearance of glandular structure, which was similar with the tree-like appearance sign in gastric MALToma. Endoscopic ultrasonography revealed the lesion to be hypoechoic, boundary-defined, and echo uniform inside, originating from the muscularis propria. Abdominal enhanced computed tomography (CT) demonstrated a soft tissue mass with defined boundary. No enlarged superficial lymph nodes were detected by B-mode ultrasound. C-urea breath test and serum antibody were both negative. The patient underwent endoscopic full-thickness resection. Postoperative pathological analysis indicated colorectal MALToma. The patient remained asymptomatic after discharge, and follow-up positron emission tomography-CT and colonoscopy showed no residual lesion, remnants or lymph node metastasis.

Conclusion: This case provides new information on the specific endoscopic features of colorectal MALToma and an alternative treatment for patients.