Port-wine stain is a congenital benign capillary malformation. It is the most common type of vascular malformation, and it persists for life. In some individuals, a port-wine stain may become more violaceous and take on a cobblestoned texture with age. In addition to being cosmetically disturbing to the patient, these lesions may be associated with a number of other findings or conditions (eg, glaucoma). They are more common in individuals of Northern European descent.

A port-wine stain may be isolated or may occur as part of a syndrome. The most common syndromes associated with such capillary malformations are as follows:

• Sturge-Weber syndrome (encephalotrigeminal angiomatosis) – There are cerebral and meningeal lesions in addition to a cutaneous lesion on the forehead. Patients may have seizures, glaucoma, intellectual disability, hemiplegia, or subdural hemorrhages.
• Klippel-Trenaunay syndrome (angio-osteohypertrophy) consists of a triad of vascular stain, hemihypertrophy, and venous varicosities. In the past, the vascular stain has been thought to be a pure capillary malformation; however, it is now recognized that it is more commonly a combined capillary, lymphatic, and/or venous malformation. Some specialists prefer to characterize this syndrome with a description of the specific malformations found in each patient.
• Phakomatosis pigmentovascularis is characterized by the coexistence of a capillary malformation and a cutaneous pigmented lesion. Both are typically present at birth.  

It is also important to note that lesions of the lower back may be associated with other skin findings such as dimples, sinuses, lipomas, and faun-tail deformities, but also with a possible underlying skeletal or neurologic abnormality such as a tethered cord.