Histopathological, histochemical and immunohistochemical studies of pyogenic granuloma and it's related lesions

Pyogenic granuloma occurs in the skin and the mucous membranes. The most characteristic features of the lesion are endothelial proliferation and formation of numerous vascular spaces. However criteria to differenciate the lesion from capillary hemangioma or epulis hemangiomatosa has never been established.We examined the histopathological, histochemical and immunohistochemical features in 5 cases of pyogenic granuloma, 6 cases of epulis hemangiomatosa and 2 cases of capillary hemangioma.1) Histopathological study by hematoxylin-eosin staining: In every cases of pyogenic granuoma and 2 out of 6 cases of epulis hemangiomatosa, ulcer formation and superficial inflammation were seen. Every cases of pyogenic granuloma and epulis hemangiomatosa revealed small lobules of proliferated endothelial cells with many vascular spaces in deeper portion of the tumor. These lobules were quite simillar to that of ordinary capillary hemangioma.2) Histochemical study by Ulex europaeus agglutinin I (UEA-I) lectin: UEA-I lectin has been known as the marker for endothelial cell of blood vessel. Endothelial cells in small lobules showed specific and strongly positive reaction to UEA-I lectin.3) Immunohistochemical study by Factor Via related antigen (F VI-RAG): Endothelial cells of lobules revealed no specific reaction to F Via-RAG.In conclusion, it is suggested that pyogenic granuloma and epulis hemangiomatosa are capillary hemangioma with granulation tissue induced by irritations such as repeated trauma or infection.