Clinicopathological characteristics of signet‐ring cell carcinoma derived from gastric fovelar epithelium

OBJECTIVE: We aimed to investigate the immunophenotype, differential diagnosis, and clinicopathological characteristics of signet‐ring cell carcinoma (SRCC) derived from gastric foveolar epithelium. METHODS: Clinical characteristics, endoscopic findings, histopathological features, and follow‐up data of seven cases of SRCC derived from gastric foveolar epithelium with small intramucosal lesions were analyzed. RESULTS: Seven patients with a mean age of 38.3 years were diagnosed with SRCC derived from gastric foveolar epithelium and small intramucosal lesions, all of them were negative for CDH‐1 germline mutation. The glands proliferated and expanded, and then morphologically transformed into signet‐ring cells and formed clonal hyperplastic SRCC, which expanded laterally along the gastric foveolar cells to a length of 3–6 mm. Periodic acid Schiff staining was positive, while CK7 and MUC6 were negative, in all cases. Ki‐67‐positive cells ranged 37%–60%. During a follow‐up period of 6–30 months, no patients experienced tumor recurrence or metastasis. CONCLUSIONS: SRCC derived from gastric foveolar epithelium is originated from the proliferative region of the bottom of the gastric pit and gland neck. It is easily missed diagnosed or misdiagnosed as it grows laterally along the gastric foveolar cells. Biological behavior, genetics, and etiology of such SRCC, as well as the clinicopathological characteristics, need to be further studied.