Objective: To study the mechanism of intralesional therapy for hemangioma with glucocorticoid. Methods: Apoptosis versus proliferation of vascular endothelial cells (VEC) in 22 specimens from 3 groups of infantile hemangioma (group 1∶ 6 involuting cases after intralesional therapy;group 2∶ 6 proliferative cases after intralesional therapy;group 3∶10 proliferative cases

never been treated)

and 5 normal skin tissues were analyzed

using the TUNEL assay to detect apoptotic cells and the proliferating cell nuclear antigen (PCNA) to detect dividing cells.In morphologic observation

light microscope was used for all of the specimens and transmissional electron microscope was used for one involuting case after treatment. Results: No sign of inflammation or necrosis was found in morphologic obsevertion in all of the cases.Apoptosis was high in 6 hemangiomas in involuting phase after treatment

and was much lower in other groups of hemangiomas and normal skin tissue.While the proliferation of VEC showed a totally reverse tendency

compared with apoptosis. Conclusion:Glucocorticoid may promote the involution of hemangioma by inducing the apoptosis and down regulating the proliferation of VEC.