An unusual subepithelial tumor of gastritis cystica profunda

Gastritis cystica profunda (GCP) is a rare disease characterized by the formation of non-neoplastic cysts that can penetrate deep into the submucosal layer of the stomach.^{1, 2} We presented two GCP cases without systemic diseases or abdominal operation history that were incidentally found by routine esophagogastroduodenoscopy (EGD) exams. We also shared different strategies for tumor resection according to endoscopic ultrasonography (EUS) evaluation.

Case one was a 51-year-old female and was transferred to our hospital due to a 0.8 cm subepithelial lesion (SEL) at gastric body (Figure 1A) found in local clinic. The EUS exam showed one polypoid lesion with mixed echoic, heterogeneous, and suspected cystic pattern originating from the muscularis mucosa layer with 9.0 × 6.0 mm² in size (Figure 1B). Based on the invasion of the muscularis mucosa layer only and its pedunculated characteristic, we conducted a polypectomy for the tumor. The specimen revealed herniation of cystically dilated glands through the muscularis mucosa into the submucosa (Figure 1C,D).

Case two was a 65-year-old female with a 1.0 cm SET at antrum on EGD (Figure 2A). The EUS revealed one 22.1 × 6.5 mm² isoechoic, heterogeneous, and suspected cystic lesion subepithelial tumor originating from the propria muscularis layer (Figure 2B). We carried out a full-layer endoscopic submucosal dissection (ESD) using a tunnel technique, with complete resection of the tumor. The pathology disclosed dilated cysts with disorganized smooth muscle in the stroma (Figure 2C), and the immunohistochemical study showed positive for CKAE1/AE3 (Figure 2D), which was compatible with the diagnosis of gastric cystica profunda.

The pathophysiology of GCP is linked to chronic inflammation and ischemia from different etiologies (such as prior gastric surgery or bacterial infections) and eventually leads to submucosal cysts formation.^{1, 2} In EUS, most GCP cases showed irregularly heterogeneous, hypo- to anechoic cystic components, and could arise from different subepithelial layers.³ As a result, the differential diagnosis from EUS finding is very challenging due to its heterogenous character and different subepithelial layers origin, and some lesions such as gastrointestinal stroma tumor, leiomyoma or ectopic pancreas should be taken into consideration. Pathology is the gold standard to make diagnosis of GCP. The malignant potential of GCP is still in debate. Treatment options include observation for the relatively small and asymptomatic cysts, and endoscopic resection or surgical excision for symptomatic or large lesions.^{4, 5} More studies and long-term surveillance is still essential for patients with GCP.

Kai-Jie Lin: Case data collection and wrote the manuscript. Hsiang-Yao Shih: Case provider and review of the manuscript. Yu-Chung Hsu: Pathological analysis. Yi-Hsun Chen: Study design, case provider, and critical review of the manuscript.

The authors declare no conflicts of interest.

Verbal informed consent was obtained for this case report. Ethics committee approval is not necessary because this is a case image report. Nonetheless, the authors followed the principles of the Declaration of Helsinki throughout the writing process.