A Case of Gastric Mucosa-Associated Lymphoid Tissue Lymphoma with Special Endoscopic Morphology

A 59-year-old man was hospitalized due to a complaint of intermittent upper abdominal distension that persisted over the duration of 2 years. Endoscopy revealed a flat depressed (type 0-IIa + IIc) and whitish lesion approximately 2.0 × 2.5 cm in size in the anterior wall of the antrum ([Fig. 1]). Reddish spots were sparsely distributed in the mucosa of the lesion. No gastric mucosa atrophy was observed. Magnifying endoscopy with narrow-band imaging (NBI) showed a nice demarcation line between the lesion and the surrounding mucosa. The morphology of the lesion surface was irregular, with minimal residual glandular fossa, as well as damage and loss of the gastric pit structure, suggesting destruction of glands. The microvessels were bifurcated, sparse, and tortuous; "tree like appearance" of the abnormal vessels can be seen in the NBI ([Fig. 2]). The 20-MHz mini-probe endoscopic ultrasound showed that all layers of the gastric wall were intact without abnormal echo ([Fig. 3]). Histopathological examination of the biopsy specimen revealed a dense small-to-medium-sized lymphoid infiltration. Immunohistochemistry analysis showed that the infiltrating cells were positive for cluster of differentiation (CD) 20, CD79a, and B cell lymphoma 2, while they were negative for CD3, CD10, and cyclin D1 ([Fig. 4]). These findings are consistent with a diagnosis of gastric mucosa-associated lymphoid tissue (MALT) lymphoma. The patient's breath test and mucosal tissue biopsy both showed negative results for Helicobacter pylori.