Gastric Adenocarcinoma Associated With CTLA-4 Haploinsufficiency in the Background of Common Variable Immunodeficiency: A Rare Case.

Common variable immunodeficiency (CVID) is associated with immune dysregulation and an increased risk of gastric malignancy. The coexistence of CVID with autoimmune gastritis, pernicious anemia, and genetic defects such as cytotoxic T-lymphocyte antigen-4 (CTLA-4) haploinsufficiency may suggest a possible association with altered gastric adenocarcinoma risk. However, the clinical interplay remains incompletely understood and not well established. We present a case of a 54-year-old Caucasian woman with a high-grade intestinal tubulovillous adenoma in the stomach body, who developed gastric adenocarcinoma, which was subsequently resected, and had a recurrence of the tumor with a background of chronic lymphocytic gastritis almost four years later. She was later diagnosed with CVID and was found to have pernicious anemia and CTLA-4 haploinsufficiency. This case highlights the potential interplay between CVID, CTLA-4 haploinsufficiency, and autoimmune gastric pathology in the development of gastric adenocarcinoma. Early recurrence despite initial curative resection underscores the need for increased vigilance and consideration of structured surveillance strategies in high-risk patients with overlapping autoimmune gastric conditions. Further research is needed to guide screening and prevention in this population.