SLC2A1 and vascular malformation: GLUT1 was first described by North et al. as a marker useful for differentiating juvenile hemangioma (which expresses GLUT1) from other vascular lesions such as vascular malformations, pyogenic granuloma, Kaposiform hemangioendothelioma, and epithelioid hemangioendothelioma (which do not express GLUT1) [10].