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

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).