Early duodenal signet-ring cell carcinoma covered by gastric foveolar metaplasia

Kazuki Horiuchi; Kei Kato

doi:10.2169/internalmedicine.7750-26

Early duodenal signet-ring cell carcinoma covered by gastric foveolar metaplasia

Intern Med. 2026 Jul 11. doi: 10.2169/internalmedicine.7750-26. Online ahead of print.

Authors

Kazuki Horiuchi^{1

2}, Kei Kato³

Affiliations

¹ Department of Internal Medicine, Japan Self-Defense Force Iruma Hospital, Japan.
² Department of Internal Medicine, National Defense Medical College, Japan.
³ Department of Pathology, Japan Self-Defense Force Iruma Hospital, Japan.

PMID: 42438031
DOI: 10.2169/internalmedicine.7750-26

Abstract

A 52-year-old man underwent esophagogastroduodenoscopy during a routine health checkup, which revealed a 15 mm semipedunculated lesion in the duodenal bulb. The initial biopsy revealed Brunner's gland hyperplasia with gastric foveolar metaplasia (GFM). A second biopsy performed 6 months later revealed signet-ring cell carcinoma (SRCC) beneath a thick overlying layer of GFM, and endoscopic mucosal resection was thus performed. The carcinoma was confined to the mucosa only. Both the SRCC and the overlying GFM exhibited a gastric-type phenotype, with an in situ lesion identified within the GFM. We report a diagnostically informative case of early duodenal SRCC.

Keywords: duodenal carcinoma; gastric foveolar metaplasia; signet-ring cell carcinoma.