Malignant melanoma.

Malignant melanoma is the most rapidly increasing cancer in Caucasians throughout the world. The increased incidence is due to greater sun exposure arising from changes in clothing habits and life-styles over the past fifty years. Most melanomas arise in preexisting moles in sun-exposed sites and may spread rapidly via the vascular system if not detected and removed early. Treatment of disseminated disease is unsatisfactory, with most patients dying of refractory brain metastases.