Gastric adenocarcinoma mimicking a submucosal tumor- a diagnostic pitfall in the pediatric population: report of two cases

Abstract

Introduction: Pediatric gastric adenocarcinoma (GAC) is sporadic with limited relevant data, and gastric adenocarcinoma, which presents as submucosal, has seldom been reported. The clinical presentation and outcome have not yet been thoroughly understood. Case presentation: Two boys (10 and 14-year-old) were admitted to the hospital with severe malnutrition. Abdominal CT demonstrated the tumor protruding into the stomach, irregular border, and peritoneal metastasis. Gastric biopsies showed pleomorphic cells, variable size, and increased N/C ratio. These cells were arranged into sheet growth patterns, clusters of cells or incomplete tubules with neutrophils infiltrating. The malignant cells showed strong expression of CK, negativity for CD99, NSE, myogenin, CD3, CD20, ALK, and CD30. Both cases were consistent with poorly differentiated gastric adenocarcinomas, diffuse type with lymphovascular invasion. Discussion and Conclusion: Pediatric GAC presented with a more advanced stage and poor differentiation. However, the clinical presentation is similar to adult GAC. Because of data limitations, the diagnosis and treatment of pediatric GAC remain a significant challenge. GAC should be kept in mind, especially when a submucosal tumor-like lesion appears in the stomach. Additional molecular investigations, including E-cadherin or HER2 testing of the tumor samples, may offer more treatment choices for these patients.