Successful Diagnosis of Gastric Heterotopic Pancreas Using Direct-Observation Biopsy by Mucosal Cutting.

CASE REPORT

A 45-year-old man was referred to our hospital for examination of a gastric subepithelial lesion (SEL). Esophagogastroduodenoscopy revealed an SEL approximately 15 mm in diameter and covered with normal mucosa in the posterior wall of the proximal gastric body (Figure 1). Endoscopic ultrasound (EUS) showed heterogeneous echogenicity and cystic structures in the lesion, which seemed to partially interrupt the fourth layer of the gastric wall (Figure 2). We suspected a malignant tumor and performed EUS-guided fine-needle aspiration (EUS-FNA). Three passes were performed using 22-gauge needles (EZ Shot 3; Olympus, Tokyo, Japan) without a rapid on-site evaluation. However, the recovered specimens were inadequate to confirm the diagnosis. The tumor did not protrude outside the gastric wall; subsequently, we considered endoscopic mucosal cutting biopsy.

Figure 1.

Esophagogastroduodenoscopy findings: A 15-mm subepithelial lesion was found in the posterior wall of the proximal body.

Figure 2.

Endoscopic ultrasound imaging: the lesion with heterogeneous echogenicity and cystic structures, which seemed to partially interrupt the fourth layer of the gastric wall.

After injecting glycerol and incising the mucosa of approximately 10 mm in length using a 2-mm FlushKnife BT-S (Fujifilm, Tokyo, Japan), we made an additional incision to expose the tumor and performed biopsies using standard biopsy forceps (FB-21K-1; Olympus, Tokyo, Japan) (Figure 3). Finally, endoscopic clip closure was performed on the incision line to prevent postoperative bleeding. No intraoperative or postoperative complications occurred. Histopathological examination revealed a gastric heterotopic pancreas (Heinrich Type I) and ruled out a malignant tumor (Figure 4). A follow-up esophagogastroduodenoscopy after 14 months showed scarring in the lesion site without any change in size.

Figure 3.

Direct-observation biopsy after exposing the tumor.

Figure 4.

Histopathological examination revealed gastric heterotopic pancreas (hematoxylin and eosin stain, magnification 100×).

Recent reports suggest direct-observation biopsy by mucosal cutting can help effectively diagnose a small gastric SEL.[1,2] Direct-observation biopsy enables direct exposure of small tumors and allows for recovery of adequate tumor samples for histopathological diagnosis[3] and may help diagnose a small gastric SEL without an extraluminal growth pattern. It is often difficult to determine whether an SEL is a malignant tumor because the histopathological diagnosis is often challenging, particularly in small gastric SELs. The lesion in this case atypically presented on the upper gastric body andwas indistinguishable from other SELs with malignant potential on EUS. EUS-FNA is the gold-standard method for obtaining samples for the pathological diagnosis of SELs. However, direct-observation biopsy could be performed after inconclusive EUS-FNA results, thereby subverting the need for unnecessary surgery.

DISCLOSURES

Author contributions: A. Michigami wrote the manuscript and is the article guarantor. Y. Otoguro and S. Maeda helped perform the procedure. S. Ichihara developed the histological images. All authors revised and edited the final manuscript.

Financial disclosure: None to report.

Informed consent was obtained for this case report.