Gastric collision tumor with diffuse large B-cell lymphoma and adenocarcinoma: a rare case report and literature review

Abstract

Background Gastric adenocarcinoma is a common malignant tumor of the digestive system. Primary diffuse large B-cell lymphoma of the stomach is a common lymphoma originating from gastric submucosal lymphoid tissue, and the coexistence of diffuse large B-cell lymphoma and adenocarcinoma is exceedingly rare. Case presentation: A 58-year-old woman came to our hospital for treatment due to a choking feeling after eating. During endoscopy, multiple irregular ulcers were seen in the fundus and body of the stomach, and the surrounding mucosa was raised. The biopsy pathology showed poorly differentiated cancer, and the patient did not undergo immunohistochemical detection. Distal gastrectomy was performed. Pathological evaluation of resected specimens showed gastric tubular adenocarcinoma and GC diffuse large B-cell lymphoma. No migration was found at the junction of the two tumors, forming a collision tumor. The patient received two cycles of R-CHOP chemotherapy, and there is no recurrence at present. Conclusion We report a case of primary gastric adenocarcinoma colliding with GC-DLBCL. Clinicians and pathologists should pay attention to this issue to avoid missed diagnoses.