Kaposi Sarcoma With Onset as Rash on Legs and Feet

A 62-year-old man consulted his physician hoping to confirm his suspicion that this lesion was benign and caused by skin friction from his watch. The 0.75-cm, purplish red, raised, rounded, dome-shaped mass with a keratin-filled crater at its top was on the patient's left distal extensor forearm. The lesion had developed within 3 weeks.

Although the lesion appeared to be a squamous cell skin cancer, Robert P. Blereau, MD of Morgan City, La, explains that its rapid development was the tip-off to the correct diagnosis-keratoacanthoma.

The lesion was excised for diagnosis and treatment. If left untreated, a keratoacanthoma will stop growing in about 6 weeks. Most of these lesions regress and eventually heal with scarring over 2 to 12 months.