Unexpected submucosal lesion with malignant potential.

Abstract

The inverted hyperplastic polyp (IHP) is known as hyperplastic gastric mucosa growth into submucosa and endoscopically presented as sessile or pedunculated submucosa lesion. It occurs in between 3.1% to 20.1% of cases, while its malignant transformation rate is just 0.02%. A male underwent esophagogastroduodenoscopy (EGD) and discovered a submucosal lesion with a pinhole-like orifice in the fundus. And endoscopic ultrasound (EUS) showed it was a heterogenous hypoechoic lesion located in the submucosa. After endoscopic resection, the pathological findings and immunohistochemical staining revealed it was inverted hyperplastic polyp (IHP) with adenocarcinoma. The measurement of the cancerous IHP depth of invasion is controversial. Thus, how to define the depth of lesion invasion in this patient needs to be seriously considered. To manage IHP with adenocarcinoma better, the depth of lesion invasion cancerous IHP needs to be seriously considered.