Primary rectal mucosa-associated lymphoid tissue lymphoma treated with only endoscopic submucosal dissection: A case report

Figure 1 Colonoscopy shows two subepithelial tumors, measuring 4 and 5 mm, within the superficial capillary bed and rising into the rectum.

Figure 2 Endoscopic ultrasonogram shows two homogenous hypoechoic lesions in the deep mucosal layer.

Figure 3 Two rectal lesions have been removed enbloc by endoscopic submucosal dissection. A: Two ESD induced ulcers; B: Tumor size was measured 5 mm × 4 mm and specimen size was measured 12 mm × 12 mm; C: Tumor size was measured 4 mm × 4 mm and specimen size was measured 12 mm × 10 mm.

Figure 4 Microscopic findings. A: Endoscopic biopsy specimens show a dense aggregate of lymphoma cells in the lamina propria (hematoxylin and eosin staining, ×20); B: Lymphoma cells infiltrate the mucosal layer above the subepithelial layer (hematoxylin and eosin staining, ×40); C: Immunohistochemical staining shows aggregate of lymphoma cells that stained positive for the B-cell marker CD20 (×400); D: Characteristic lymphocyte-epithelial lesion of CD20-positive lymphoma cells was also observed (x400).