Phakomatosis pigmentovascularis (PPV) is a rare congenital syndrome that consists of the coexistence of a capillary malformation and a cutaneous pigmented lesion. Both are typically present at birth and affect all racial and ethnic groups. According to the most recent classification system, PPV can be divided into 5 main subtypes:

1. Nevus flammeus plus epidermal nevus
2. Nevus flammeus plus dermal melanocytosis with or without nevus anemicus
3. Nevus flammeus plus nevus spilus with or without nevus anemicus
4. Nevus flammeus plus dermal melanocytosis plus nevus spilus with or without nevus anemicus
5. Cutis marmorata telangiectatica congenita plus dermal melanocytosis

Each of these subtypes may be skin limited or may have associated systemic manifestations, most commonly Sturge-Weber syndrome or Klippel-Trenaunay syndrome. Neurologic, ocular, musculoskeletal, and/or visceral abnormalities may be present. It is estimated that systemic findings exist in up to 50% of cases.

The pathophysiology of PPV is poorly understood. One theory suggests abnormalities in neuroectodermal precursor cells that later differentiate into melanocytes and vasomotor nerve cells. Mosaic-activating mutations in PTPN11 have been identified in patients with PPV type 3, as have mosaic-activating mutations in GNA11 and GNAQ in types 1, 2, and 4.