Clinicopathological features and diagnostic challenges of early gastric cardiac carcinoma with dysplastic gastritis cystica profunda: A case report.

Gastric cardiac carcinoma associated with dysplastic gastritis cystica profunda (GCP) with represents a rare clinicopathological entity. Its distinct histological features pose diagnostic challenges, as GCP with mild dysplasia can mimic invasive carcinoma, potentially leading to overdiagnosis, overtreatment, and increased patient morbidity. We report a case of early gastric cardiac carcinoma with dysplastic GCP, treated by endoscopic submucosal dissection (ESD). Histopathological examination revealed a moderately differentiated tubular adenocarcinoma confined to the mucosa, adjacent to submucosal cystic glands exhibiting mild dysplasia, cystic dilation, abundant mucin secretion, and focal mucin pools. Immunohistochemically, the carcinoma was positive for CK7 but negative for MUC2 and MUC5AC, while the cystic glands showed the opposite profile. The Ki67 proliferative index was significantly lower in the cystic glands than in the carcinoma. The final diagnosis was intramucosal moderately differentiated adenocarcinoma of the gastric cardia with mildly dysplastic GCP. No recurrence was observed during the 12-month follow-up. This case highlights the diagnostic pitfalls of this entity, and underscores the importance of accurate pathological recognition to guide clinical management.