SLC2A1 and Maffucci syndrome: GVMs, previously known as “glomangiomas,” are characterized by the presence of undifferentiated smooth muscle cells (glomus cells) surrounding convoluted venous channels.6 Histologically, Maffucci syndrome vascular lesions are characterized by spindle cells, and thus called “spindle cell hemangiomas.” Verrucous venous malformations (VVMs) are composed of clusters of GLUT1-positive venous-like channels associated with various degrees of epidermal hyperplasia/hyperkeratosis.