Vascular malformations are congenital dysmorphic vessels that are present at birth but may not become clinically apparent until later in life. They may worsen in severity with age and persist if untreated [1]. The updated International Society for the Study of Vascular Anomalies classification divides vascular malformations into four types: simple, combined, major named vessel(s), and associated with other anomalies [2]. Vascular malformations can also be subdivided accordingay be responsible for both venous and lymphatic malformations. These vascular malformations are congenital and are due to sporadic somatic mutations in 2 genes. To date, 60% of venous malformations have an activating mutation in the TEK (TIE2) gene, which encodes the TIE2 receptor tyrosine kinase on endothelial cells, and 20% of venous malformations have a mutation in the PIK3CA gene, which results in excessive activation of phosphoinositol 3-kinase (PI3K). These two mutations induce excessive activation of intracellular signaling cascades and in particular the PI3K/AKT/mammalian target of rapamycin (mTOR) pathway), leading to uncontrolled endothelial cell proliferation and disruption of pericyte coverage. These mutations lead to hyperactivation of the PI3K pathway, resulting in abnormal tissue growth, including epithelial and mesenchymal cells. The resulting proliferative syndromes often include slow-flow vascular malformations: lymphatic and venous and vascular malformations, which explains the efficacy of treatment with specific therapies, in particular sirolimus [5].