Abstract
BACKGROUND: A gastric hamartomatous inverted polyp (GHIP) is an uncommon submucosal neoplasm that is histopathologically defined by a submucosal inverted growth of cystically dilated hyperplastic gastric glands. CASE PRESENTATION: A 74-year-old Chinese man presented with a submucosal tumor (SMT) in the cardia, identified through electronic gastroscopy. This report presents a case of cardia hamartomatous inverted polyp (CHIP), which represent a rare histological variant of gastric polyps that pose diagnostic challenges. The endoscopic examination revealed the presence of a submucosal tumor, and endoscopic ultrasonography indicated a heterogeneous tumor predominantly situated within the third (submucosal) layer. Immunohistochemistry outcomes indicated MUC5AC (+), MUC6 (+), Syn (+), Ki-67 (+, approximately 5%), Desmin (+), SMA (+), as well as MUC2 (-). To achieve en bloc resection for lesions >1.0 cm, endoscopic submucosal dissection (ESD) was performed. The pathological evaluation confirmed the diagnosis of CHIP. The patient was discharged without experiencing any complications. CONCLUSION: Therefore, the ESD approach may be particularly suitable for the management of SMT-type hamartomatous inverted polyps.