Some special skin tumours in the elderly.

A review of uncommon skin tumours, all of which characteristically arise in elderly patients, is presented. Angiosarcoma of the face and scalp is a highly progressive tumour with a poor prognosis, but initially it may be misdiagnosed as a simple bruise or cellulitis. In well-differentiated tumours a characteristic feature is interlacing endothelial cell-lined channels showing considerable nuclear atypia. Merkel cell tumours, which develop as deep-seated nodules in the skin, occur most frequently in photodamaged areas, especially on the head and neck. The prognosis of Merkel cell tumours is generally poor; histological evidence suggests that some of these tumours may be a special type of poorly differentiated squamous cell carcinoma. Atypical fibroxanthoma, which is normally benign, occurs most frequently in elderly, fair-skinned males, especially around the face. It is typically a polypoid lesion with a vascular appearance. Acantholytic squamous cell carcinomas, also known as adenoid squamous cell carcinomas, are most common in fair-skinned men with a history of keratoses. They also occur in the female genital region and the oral mucosa. Histologically, these tumours differ from squamous cell carcinomas because of their tendency to form duct-like areas in tumour lobules.