The patients we described, in whom we found mutations in genes involved in the PI3K/AKT/mTOR pathway, reflect the literature in three cases (two of Klippel–Trénaunay syndrome and one of venous malformation), while one case of arteriovenous malformation and one case of kaposiform hemangioendothelioma showed mutations in TEK and PIK3CA genes, respectively. The gene discussed is AKT1; the disease is kaposiform hemangioendothelioma.