Malignant blue nevus of the scalp.
A 70-year-old woman had noticed, at the age of 30, a single blue nodule of about 1 cm in size on her scalp. The lesion remained stable until 1991, when it became larger and ulcerated and, because of the sudden onset of additional macules and nodules around it, the patient presented at our Dermatological Division in August 1992. Physical examination showed a blue-black plaque, 2 x 2 cm in size, on the left parietal area of the scalp, surrounded by several blue-grey pigmented nodules and macules (Fig. 1). Chest X-ray, abdomen scan, and a total body computed tomography (CT) scan were negative for metastatic disease. A wide resection of the scalp lesion was performed. The histologic evaluation revealed a dense collection of spindled melanocytes in the dermis and in the subcutaneous fat. Nuclear and cytoplasmic pleomorphism, some mitotic figures, and necrosis foci were present (Figs 2 and 3). Pictures of cellular blue nevus were found in the surrounding lesions. Ten months later, new blue macular and papular lesions appeared in proximity to the surgical scar. The patient refused any additional surgery, and so was treated with dacarbazine (DTIC) 800 mg intravenously (every 20 days) and 2 alpha interferon (3 million units subcutaneously, three times weekly). The growth of the lesions slowed down for a few weeks, and then increased again to become a wide, blue-black vegetating mass (Fig. 4). In June 1995, a total body CT scan revealed multiple focal nodules on the lungs and two metastatic masses on the eighth segment of the liver. A palliative polychemotherapy, with vindesin 3 mg/m2 and DTIC 400 mg/m2, was started, but did not stop the progression of the disease, and the patient died in December 1996.