A. By Flow Type Slow-flow Malformations:
Capillary malformations (CM): Also called port-wine stains or nevus flammeus. Typically flat, red or pink discolorations of the skin. Venous malformations (VM): Abnormal development of veins. Compressible, bluish, and enlarge with dependency or Valsalva maneuvers. Lymphatic malformations (LM): Formed by dilated lymphatic vessels. May present as cystic masses (microcystic, macrocystic, or mixed). Commonly associated with swelling and recurrent infections. Fast-flow Malformations:
Arteriovenous malformations (AVM): Direct connections between arteries and veins without an intervening capillary bed. Often pulsatile and may present with bruit, thrill, or bleeding. Arteriovenous fistulas (AVF): Abnormal direct communication between an artery and a vein. Can lead to high-output cardiac failure if large. Mixed-flow Malformations:
Combinations of the above types, such as arteriovenous malformations with lymphatic or venous components. B. By Location Cutaneous (skin) Mucosal (oral or genital lining) Musculoskeletal (muscle or bone) Visceral (internal organs)