Segmental outgrowth-lipomatosis-arteriovenous malformation-epidermal nevus syndrome

Segmental outgrowth-lipomatosis-arteriovenous malformation-epidermal nevus syndrome (SOLAMEN syndrome) is an extremely rare mosaic overgrowth disorder characterized by the combination of segmental (localized) body overgrowth, lipomatosis (abnormal fatty tissue growths), arteriovenous malformations (abnormal connections between arteries and veins), and epidermal nevi (benign skin growths). This condition is considered a segmental manifestation of Cowden syndrome (PTEN hamartoma tumor syndrome) caused by postzygotic (somatic) mosaic mutations in the PTEN gene, which is a tumor suppressor gene. The disorder affects multiple body systems including the skin, soft tissues, vasculature, and skeletal system. Clinical features typically present at birth or during early childhood and may include asymmetric or segmental overgrowth of a limb or body region, multiple lipomas, vascular malformations (particularly arteriovenous malformations), and epidermal nevi following a pattern along the lines of Blaschko. Patients may also develop features overlapping with Cowden syndrome, including an increased risk for certain tumors, particularly if a germline PTEN mutation coexists with the somatic mutation (a phenomenon known as type 2 segmental mosaicism). Macrocephaly and other hamartomatous growths may also be observed. There is no curative treatment for SOLAMEN syndrome. Management is multidisciplinary and symptom-based, involving dermatologists, vascular specialists, orthopedic surgeons, and oncologists. Treatment may include surgical removal of lipomas or epidermal nevi, embolization or other interventional procedures for arteriovenous malformations, and enhanced cancer surveillance given the association with PTEN mutations. Emerging therapies targeting the PI3K/AKT/mTOR pathway, which is dysregulated due to PTEN loss, are being investigated in related overgrowth syndromes and may hold future promise.

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