Recurrent epithelioid angiosarcoma of the scalp simulating melanoma. A 10-year follow-up.

We present a case of an intriguing mesenchymal neoplasm of the scalp that recurred several times over 10 years before a final diagnosis was possible. The case was sent for expert opinions to various international dermatopathological authorities and was, for a long time, unanimously interpreted as malignant melanoma. This diagnosis was supported by immunohistochemical examinations demonstrating S-100 positivity. Nevertheless, the clinical behaviour, as well as some histopathological features raised doubt regarding the diagnosis. Only after the last recurrence, followed by a repeat extensive immunohistochemical study, the diagnosis of epithelioid angiosarcoma was made. Histologically malignant melanoma can be highly misleading and in literature, reports of misinterpreted cases of melanoma are published. In contrast, tumours that can simulate melanoma are also not infrequent and it is essential to perform immunohistochemistry to confirm diagnosis and exclude a melanocytic lesion.