Gastric carcinosarcoma presenting as a huge epigastric mass.

Gastric carcinosarcoma often presents with an elevated lesion or increased thickness of the stomach wall. Histological diagnosis is achieved using conventional hematoxylin and eosin staining to confirm the coexistence of both epithelial and mesenchymal elements. We report a case of gastric carcinosarcoma presenting as a large mass in the epigastric region. Specimens obtained by endoscopic biopsy and surgical excision showed diffuse proliferation of atypical cells in sheet formation. No mucus production or glandular structures were apparent, but immunoreactivity for both epithelial and mesenchymal markers was noted. These findings led to a definitive diagnosis of gastric carcinosarcoma. Immunohistochemical analysis is useful for the early diagnosis and treatment of gastric carcinosarcoma.