METASTATIC MALIGNANT BLUE NEVUS - A CASE-REPORT

This report presents a 63-year-old Caucasian woman with a malignant bl ue nevus, which is an extremely rare form of melanoma originating from or associated with a preexisting blue nevus. The background blue nevu s on the left upper arm, wh ich had been present for 5 to 6 years, inc reased in size and darkened in color for 3 months prior to histologica l diagnosis of malignant blue nevus. Although the tumor looked much li ke a nodular melanoma clinically, the diagnosis of malignant blue nevu s was established histologically. The patient had a poor outcome due t a metastatic spread of the tumor to the visceral organs 1 year followi ng the initial excision of the tumor. To distinguish this rare tumor f rom other melanocytic lesions, strict histological criteria are needed to make the diagnosis of malignant blue nevus. Differential diagnosis includes cellular blue nevus, atypical cellular blue nevus, primary m alignant melanoma, and metastatic melanoma to the dermis. Malignant bl ue nevus is most commonly seen on the scalp. The tumor has an aggressi ve behavior and metastasizes in the majority of patients. This paper d escribes the second reported case of malignant blue nevus involving th e upper arm. Clinical and histological features of this uncommon tumor are presented, along with a review of the literature.