[Merkel cell carcinoma: a treacherous skin tumor]

Merkel cell carcinoma is a rare malignancy of the skin in predominantly elderly patients, frequently missed because of its inconspicuous aspect. The histological diagnosis is not always easily made. Four case histories are presented. Literature shows the aggressive biological behaviour of this tumour: the rate of local recurrence is 40%, of regional metastatic disease over 50%, while approximately half the patients with a Merkel cell carcinoma will die of this skin tumour.