2022 Volume 64 Issue 10 Pages 2268-2274
A 66-year-old man was referred to our hospital for further evaluation of a polypoid lesion of the stomach detected on radiographic examination. Esophagogastroduodenoscopy revealed a broad-based elevated lesion (24mm) with a relatively steep but smooth surface and submucosal tumor-like morphology in the upper body of the stomach, with an edematous red apex and a shallow ulcer. Endoscopic ultrasonography revealed a lesion of low echogenicity with multiple aechoic images in the mucosal-submucosal layers, and we performed endoscopic resection using a snare followed by circumferential incision and submucosal dissection using ESD techniques. Histopathological examination of the resected specimen revealed that the polypoid lesion was composed of submucosal proliferation of cystically dilated gastric glands and fibromuscular elements. Based on these findings, we diagnosed the tumor as a hamartomatous inverted polyp (HIP). Only six cases (including the current case) of HIP with ulceration have been reported in Japan, which indicates the rarity of this form of HIP. The atypical ulcer observed in this case of HIP was probably attributable to mechanical stimulation. HIP is rare and is known to be complicated by cancer. Therefore, preoperative diagnosis is invariably challenging, and it is important to carefully devise the optimal treatment strategy.
