A Case Report of Bronchogenic Cyst in the Posterior Wall of Gastric Fundus With Elevated CEA and CA199 in Cystic Fluid.

Bronchogenic cysts originate from abnormal foregut budding during embryogenesis. Two pathogenic mechanisms exist: (1) ectopic migration of tracheobronchial precursors forming cysts in extrapulmonary sites, and (2) retained bronchial buds developing pulmonary cysts through mucus accumulation. Despite anatomical variations, all cysts retain respiratory epithelium with mucinous glands, pathognomonically reflecting their embryological origin. Herein, we report an unusual case of bronchogenic cyst in the posterior wall of the gastric fundus with elevated CEA and CA199 in cystic fluid. CT showed that a kind of circular soft tissue density shadow was visible under the submucosa of the stomach floor, with a size of about 3.9 × 3.7 cm, uniform density, and clear boundary. Pathology after surgical resection of the gastric tumor: the cystic wall-like tissue was locally lined with ciliated columnar epithelium, the mucosa showed chronic inflammation, and foreign body giant cell reaction, calcification, and ossification were observed in the submucosa. The patient was diagnosed as having a bronchogenic cyst in the posterior wall of the gastric fundus and was followed up for 12 months after the operation, with no obvious discomfort.