Rare primary rectal mucosa-associated lymphoid tissue lymphoma with curative resection by endoscopic submucosal dissection: A case report and review of literature

Figure 1 Endoscopic findings. A: A 3.0 cm x 3.5 cm laterally spreading tumour-like elevated lesion was observed in the rectum; B: Indigo carmine staining showed a clear margin and uneven surface; C-F: Narrow band imaging (C) and magnifying endoscopy (D, E, F) showed a dark brown background and enlarged branch-like vessels on the surface of the lesion; G and H: Crystal violet staining magnifying endoscopy showed that the pit pattern structure disappeared on the surface of the lesion; I: Hypoechoic thickening of the mucosal layer was detected by endoscopic ultrasound.

Figure 2 Endoscopic submucosal dissection. A, B, and C: The lesion was completely removed by endoscopic submucosal dissection.

Figure 3 Histopathological findings (haematoxylin and eosin staining). The histopathological findings of the endoscopic submucosal dissection specimen showed diffusely hyperplastic lymphoid tissue with a lymphoid follicle structure surrounded by an abundance of diffusely infiltrated lymphoid cells that exhibited clear cytoplasm and similar sizes. The lymphoma invades the mucosal layer inside. A: Magnification of 2000 μm; B: Magnification of 200 μm; C: Magnification of 50 μm.

Figure 4 Immunohistochemical findings. A-C: CD20, CD19, and CD 79α immunohistochemical staining were positive; D: Ki-67 Labelling; E-H: BCL-6, cyclin D1, CD3, and CD 56 immunohistochemical staining were negative. The magnification of all photographs is 200 μm.

Figure 5 Colonoscopic follow-up after endoscopic submucosal dissection. A: A smooth surgical scar was observed 6 mo after endoscopic submucosal dissection (ESD); B: A smooth surgical scar was observed 1 yr after ESD; C: A smooth surgical scar was observed 2 yr after ESD.