[2 cases of gastric mucosa-associated lymphoid tissue lymphoma presenting as a submucosal tumor-like lesion]

Gastric Mucosa-associated Lymphoid Tissue Lymphoma: An Important Differential Diagnosis for a Rapidly Growing Gastric Subepithelial Tumor - A Case Report and Literature Review

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is a low-grade lymphoma with a long median survival time because of its low proliferation rate. A 75-year-old man was referred to the hospital for hematemesis. Upper endoscopy revealed a 30-mm subepithelial tumor (SET). Abdominal CT and EUS revealed a homogeneously hypoechoic lesion arising from the second layer of the stomach, without distant metastasis. Laparoscopic wedge resection was performed. On microscopic examination, the tumor showed diffuse aggregation of small lymphoid cells with abnormal architecture. Neoplastic cells showed positive reactivity for CD20 and prominent lymphoepithelial lesions were observed. The urease breath test was also conducted, with a negative result. Our final diagnosis was <i>Helicobacter pylori</i>-negative MALT lymphoma (Ann Arbor classification I_E2), which is a rapidly growing SET pattern. This case highlights the importance of including gastric MALT lymphoma as a differential diagnosis for rapidly growing gastric SETs.

Successful Endoscopic Resection of Gastric Mucosa-Associated Lymphoid Tissue Lymphoma Unresponsive to Helicobacter pylori Eradication Therapy

Eradication of Helicobacter pylori is the first-line treatment for gastric mucosa-associated lymphoid tissue (MALT) lymphomas; however, lesions may persist in 20% of patients after initial treatment, thereby necessitating the use of an additional therapeutic approach. Other treatment options include radiation therapy, chemotherapy, endoscopic resection, rituximab therapy, or watchful waiting. We present a case of localized gastric MALT lymphoma that did not respond to H. pylori eradication therapy. The patient waited for 12 months but the tumor showed no signs of regression endoscopically. Histologic examination revealed residual MALT lymphoma. The tumor was then successfully treated using endoscopic submucosal dissection and the patient remained disease-free for 4 years. To our knowledge, this is the first case in which a gastric MALT lymphoma was treated with endoscopic submucosal dissection. In conclusion, endoscopic resection may be recommended as second-line therapy for properly selected patients with gastric MALT lymphoma as it is effective and minimally invasive.

Primary Mucosa-associated Lymphoid Tissue Lymphoma Metachronously Involving Esophagus and Stomach

Mucosa-associated lymphoid tissue (MALT) lymphoma is found in various organs as extranodal B cell lymphoma. The gastro-intestinal tract is the most commonly involved extranodal site in MALT lymphoma. However, primary esophageal MALT lymphoma is very rare. In addition, few cases with metachronous gastric involvement have been reported. A 55-year-old man was diagnosed with MALT lymphoma by surveillance esop hagogastroduodenoscopy. A 5 cm esophageal submucosal tumor-like lesion was incidentally revealed by screening esophagogastroduodenoscopy two years prior. Esophagogastroduodenoscopy showed a cylin-drically elongated submucosal mass with normal overlying mucosa in the mid esophagus. He underwent surgery to confirm the diagnosis. The pathologic diagnosis was esophageal MALT lymp homa. He was treated with radiation, which achieved complete remission. Esophagogastroduodenoscopy and chest computed tomography were performed every three to six months, with no evidence of recurrence for 18 months. After 21 months, severa l elevated gastric erosions were found on the great curvature and posterior sides of the midbody and confirmed as MALT lymphoma pathologically. Here we report a case with MALT lymphoma metachronously involving the esophagus and stomach.

Undiagnosed Borrmann type II gastric cancer due to necrosis and regenerative epithelium

Endoscopic biopsy is essential to the proper diagnosis and treatment of gastric cancer. Unfortunately, the results of endoscopic biopsy are not always the same as what is expected based on gross endoscopic findings. The results of endoscopic biopsy can be negative for malignancy in Borrmann type IV advanced gastric cancer (AGCa) or gastric lymphoma. However, in the case of type II AGCa, repeated biopsies negative for malignancy have not been reported. A 49-year-old male patient underwent esophagogastroduodenoscopy three times due to large gastric ulcer suspected to be Borrmann type II cancer. However, three repeat endoscopic biopsies with multiple specimens showed necrosis and superficial regenerative epithelium without malignant findings. The patient underwent laparoscopic distal gastrectomy with D2 lymph node dissection. The surgical specimen revealed that the mucosal layer was completely replaced with regenerative epithelium without cancer cells.