New lasers and improved laser delivery systems have allowed for the safe and effective treatment of port-wine stains in patients of all ages. The satisfactory results obtained by laser treatment have increased the number of patients seeking consultation regarding their birthmarks. It is imperative that physicians recognize the various medical syndromes and problems associated with port-wine stains. A review of 415 patients with facial port-wine stains has revealed hypertrophy and/or nodularity in 65% of patients by the fifth decade of life, which increases significantly the morbidity of these lesions. It is believed that laser treatment will minimize the medical and psychologic complications that result from the natural evolution of port-wine stains. J Dermatol Surg Oncol 1991; 17:76-79. Recent developments in the treatment of port-wine stains have allowed physicians to re-evaluate the opportunity and necessity for treatment of these lesions. Port-wine stains occur in 0.03% of the general population and are noted to occur most commonly on the face over the areas of the first and second trigeminal nerves. In the past several years, the development of the flashlamp-pumped pulsed-dye laser, continuous-wave tunable-dye yellow-light laser, copper vapor laser and the use of other continuous-wave lasers in conjunction with special scanning devices, have all led to improved results in the treatment of these lesions. One of these lasers (the flashlamp-pumped pulsed-dye laser) has even allowed for the treatment of infants and young children. Thus, physicians and patients afflicted with this congenital anomaly are faced with the decision of whether or not to seek treatment with any of these lasers, where previously treatment may have been unsatisfactory or contraindicated. The superior results now offered by lasers in the treatment of port-wine stains have also allowed for the influx of patients with this congenital malformation to seek medical attention. Thus it is important that those physicians consulting these patients recognize the associated medical problems that may be found with port-wine stains. One important example is the Sturge-Weber syndrome, which is commonly found among those patients with port-wine stains involving the distribution of the first branch of the trigeminal nerve. The Sturge-Weber syndrome has a high incidence of congenital glaucoma of the ipsilateral eye, calcification and vascular anomalies of the brain, associated seizure disorders, and in some cases, mental redardation. Ophthalmologic and neurologic evaluation in these patients are recommended early in life. Other congenital syndromes associated with port-wine stains include the Klippel-Trenaunay-Weber syndrom with the associated hypertrophy of skeletal tissue, as well as the Cobb syndrome, which may be a sign of underlying arteriovenous malformation of the spinal cord. It is also not uncommon to see a port-wine stain overlying an arteriovenous malformation, arterial malformation, or venous malformation, therefore requiring the physician to look beyond the skin for any underlying problem. Port-win stains begin as macular lesions and become progressively ectatic over time. This progressive ectasia can result in significant darkening of the lesion as well as the development of nodularity and occasional tumors. A review of 415 patients presenting at the laser section of the Skin and Cancer Unit of New York University Medical Center has revealed that approximately two-thirds of all patients with port-wine stains develop nodularity or hypertrophy in the fifth decade of life. These changes are gradual in their development, with the mean age of hypertrophy noted to be 37 years. The progression of the port-wine stain from its macular stage to the hypertrophic stage may take place at any point in the development of an individual's lifetime; however, the most dramatic changes are noted as the patient has become older. Associated with this nodularity and hypertrophy is the risk of spontaneous bleeding and hemorrhaging upon injury to the affected area. Although the exact risks have not been established in the literature, they are clearly associated with the degree of hypertrophy and the location of the lesion. Men with port-wine stains on the face in the bearded area run significant risks of excessive bleeding upon shaving, as would a woman with a port-wine stain in the hair-bearing area where epilation is desired. The development of hypertrophy or nodularity in a periorbital area may inhibit the visual field and, similarly, these changes around the nose or mouth may also interfere with breathing or eating. It has become clear that treatment of a port-wine stain in its macular stage will prevent the development of the hypertrophic component of the lesion. Postoperative biopsies upon laser treatment of a port-wine stain reveal that the existing blood vessels are smaller and fewer in number compared with pretreatment biopsies. Thus, the opportunity for the progression of these lesions to a more ectatic state is less likely to occur. Not uncommonly, the development of pyogenic granulomas in patients with port-wine stains can occur and these pyogenic granulomas have the potential to also bleed spontaneously. In our experience, the incidence of pyogenic granulomas is significantly lower in those patients who have been treated with laser therapy. The psychological problems associated with a congenital birthmark of this type may have short and long-term implications for the patient. Detailed studies have demonstrated lower self-esteem and problems with social interaction for both the patient and family alike. Successful treatment of a port-wine stain with any modality helps minimize psychological problems that occur as a result of the presence of the port-wine stain. Although the treatment of these lesions has imporved dramatically over the past several years with the development of newer techniques and lasers, many patients are denied the opportunity for treatment of these lesions by the unfortuante classification of this treatment as a cosmetic procedure. It has been demonstrated clearly that these safe treatments can minimize the chance of nodularity, spontaneous bleeding, and the development of pyogenic granulomas. The psychologic benefits of removing port-wine stains in these patients are of considerable value to their mental health and may, in fact, obviate the need for psychological counseling at a later date. It is incumbent upon those physicians who evaluate patients with port-wine stains and insurance carriers who evaluate their claims to realize the medical benefits in the treatment of these lesions. Failure to recognize the treatment of port-wine stains as a medical necessity may, in fact, be harmful to the medical and psychologic well-being of the patient.