2024 Volume 66 Issue 11 Pages 2556-2562
The association between Helicobacter pylori （H. pylori） infection and gastric mucosa-associated lymphoid tissue （MALT） lymphoma and gastric carcinoma is well known. However, the occurrence of both these diseases is rare. Here, we report a case of a collision tumor comprising MALT lymphoma and early gastric cancer in a stomach uninfected by H. pylori. A 71-year-old man diagnosed with gastric cancer on physical examination was referred to our hospital. Upper gastrointestinal endoscopy showed a 15 mm area of faded mucosa with an adjacent 7 mm area of reddened mucosa in the greater curvature of the upper gastric body. Biopsy indicated that the former was a MALT lymphoma and the latter was a moderately differentiated adenocarcinoma. Since gastric mucosal atrophy was not observed, H. pylori antibody in the serum was less than 3 U/mL, H. pylori microscopic examination of the resected specimen was negative, and there was no history of eradication, the patient was identified as H. pylori- uninfected. EUS revealed that the cancer had invaded deep into the submucosal layer. Chest and abdominal CT revealed no lymph node enlargement. Tumor marker and soluble IL-2 receptor levels were within normal range. A segmental gastrectomy with lymph node dissection was performed. Histological examination of the resected specimens showed contact between the MALT lymphoma and the early gastric cancer. Both lesions were successfully treated and neither local recurrence nor metastasis was observed.
