Multiple cutaneous melanoma metastases

An 84‐year‐old white woman presented with diagnosed vascular failure in the left leg. The patient had had diabetes mellitus for over 50 years. Five years earlier, her right leg was amputated because of an obliterating arteriopathy. At the time of hospitalization, she showed dry gangrene in all the toes on her left foot. A laser Doppler test performed on the left leg showed severe peripheral arteriopathy affecting the anterior and posterior tibial arteries, with a Windsor index of 20% in her ankle. On physical examination, the patient showed several nodular lesions on the anterior and anterior‐medial surface of her left leg. These lesions were infiltrated, of a hard elastic consistency, and occasionally confluent, with a diameter ranging from 0.5 to 4 cm (Fig. 1) and the color varying from ochre‐yellow to brownish‐red to slate‐brown. The patient reported that these lesions had erupted approximately 2 years earlier and had been accompanied by itching and mild burning. She had shown them to her family doctor who had diagnosed seborrhoeic keratosis. A series of biopsies performed on the nodules revealed the presence of atypical melanocytes arranged in alveolar formations that reached the epidermis. The epidermis appeared thin, compressed, and atrophic; no signs of junctional activity could be seen (Fig. 2). The tumor cells were round, with a clear cytoplasm and atypical, hyperchromatic, oval nuclei containing nucleoli (Fig. 3). Some atypical melanocytes contained small amounts of melanic pigment that was concentrated in the cytoplasm of macrophages which were mixed with the elements of the tumor. There had been no melanoma in the clinical history of the patient. The patient had a chest roentgenogram with tomography and a computer tomography (CT) scan of the liver, spleen, mediastinum, and brain, all with negative results. The case is worth reporting because of the peculiar cutaneous lesions that could suggest several diagnostic hypotheses. The clinical picture could have been interpreted as being Kaposi's sarcoma, seborrhoeic keratosis, angiosarcoma, or multiple Spitz nevi. A Spitz nevus is a benign variant of a compound nevus that is characterized histopathologically by atypical, large melanocytes with abundant eosinophilic cytoplasm and large vesicular nuclei with prominent nucleoli. Histologic examination removed any doubt, suggesting a metastatic origin for the proliferating nodules. Marked expression of S‐100 protein and of HMP45 was found by immunohistochemistry; HMP45 was also intensely positive in the deep layers of the dermis. It was not possible to define the site of the primary lesion from the patient's history or from physical examination; 1,2 however, one cannot exclude that the primary lesion was at the same site as where the metastases had diffused, either by growing spontaneously from healthy tissue or through a transformation of anevus. 3,4