BackgroundGastric duplication cysts are uncommon congenital anomalies found primarily in children and rarely seen in the adult population. Accurate diagnosis of cysts before resection is difficult even using the most advanced imaging techniques.Case presentationIn this report, we describe a 28-year-old Moroccan patient with a history of autoimmune hemolytic anemia who presented with an asymptomatic abdominal cystic mass detected during abdominal computed tomography performed before splenectomy. Magnetic resonance imaging performed for accurate characterization showed a high-signal-intensity cystic mass on T2-weighted images, located between the patient’s stomach and spleen. The patient underwent a complete cyst resection during exploratory laparotomy. The histological examination showed a cyst lined by three different epithelia with bundles of smooth muscle, which suggested a gastric duplication cyst.ConclusionsWe report a case of gastric cyst duplication in an adult with autoimmune hemolytic anemia, and we discuss this rare association, radiological findings, and the unique histological findings of this case.