Venous Malformation

Venous malformation (VM) is the most common slow-flow congenital vascular malformation, present at birth and growing proportionally with the child throughout life. It consists of ectatic dysmorphic venous channels with deficient or abnormal smooth muscle wall, leading to slow flow, stasis, intravascular thrombosis with phlebolith formation, and localized intravascular coagulopathy. VMs are sporadic in 95% of cases; familial forms are linked to TIE2/TEK mutations or PIK3CA somatic mosaicism.

Clinical features include bluish soft compressible mass that empties with elevation and refills with dependency or Valsalva, pain especially on awakening due to overnight stasis and microthrombi, localized swelling and disfigurement, episodic pain from acute thrombosis, and complications such as deep vein extension, joint involvement (intraarticular VM with hemarthrosis), airway involvement, and disseminated intravascular coagulopathy in extensive cases.

MRI is the gold standard imaging modality showing T2 hyperintense, lobulated lesion with characteristic fluid–fluid levels and phleboliths (signal void on T1/T2). Phlebography helps plan sclerotherapy. Treatment is multidisciplinary. Sclerotherapy (ethanol, sodium tetradecyl sulfate, bleomycin, polidocanol foam) is first-line, often requiring multiple sessions. Surgical excision is reserved for localized lesions or when sclerotherapy fails. Sirolimus is effective for extensive or complex venous malformations. Aspirin or low-molecular-weight heparin manages localized intravascular coagulopathy. Compression garments help limb VMs.