Clinicopathological features of gastric Langerhans cell histiocytosis and a literature review.

Objective This study aims to review the clinicopathological features, molecular profiles, and clinical behavior of gastric LCH to increase diagnostic accuracy and improve the understanding of its prognosis. Methods We analyzed five cases of gastric LCH and integrated clinical, endoscopic, and pathological data. Diagnoses were confirmed via immunohistochemistry (S-100, CD1a, and Langerin). BRAF-V600E mutation status was assessed by PCR in three patients. A literature review of 17 additional cases was included for a comprehensive analysis. Results Patients presented with nonspecific symptoms such as abdominal pain. Endoscopy predominantly revealed solitary polyps (<1 cm) or mucosal thickening, primarily in the gastric body. Histology revealed characteristic neoplastic cells with grooved nuclei and eosinophilic cytoplasm, accompanied by eosinophil infiltration. All patients were positive for S-100, CD1a, and Langerin. The BRAF-V600E mutation was detected in all three tested cases. Systemic involvement occurred in two patients. Treatment ranged from surveillance to chemotherapy. All patients were alive after follow-up (8-62 months), with most patients showing no progression. Conclusion Gastric LCH typically presents as a small, solitary polyp. S-100, CD1a, and Langerin positivity was observed by immunohistochemistry. The high frequency of BRAF-V600E mutations provides a diagnostic adjunct and potential therapeutic target. Gastric LCH patients have a good prognosis and long overall survival when the cancer is a localized lesion. However, systemic involvement may necessitate chemotherapy, and regular follow-up is recommended.