Disorders of the venous system

In the chapter, we describe variable lesions affecting the peripheral venous system. Glomuvenous malformation is the most common inherited venous malformation. It is histologically characterized by abnormal differentiation of vascular smooth muscle cells. The lesions are painful. The rare inherited mucocutaneous venous malformation (VMCM), and the much more frequent sporadic forms, including sporadic unifocal VM (VM), multifocal sporadic VM (MVM), Blue-rubber bleb nevus syndrome (BRBN), hyperkeratotic cutaneous capillaro-venous malformation (HCCVM), verrucous VM (VVM), and VMs associated with syndromes, all affect vascular endothelial cells. The molecular bases and pathogenesis of these lesions has become more clear during recent years with the discovery of the mutated genes in the majority of these lesions. This has opened the era of repurposing cancer drugs as molecular therapies for these defects