[Merkel cell tumor or neuroendocrine skin carcinoma]

Merkel cell carcinoma is a rare malignant tumor of the skin with predominance in older patients; 78.6% of patients are older than 59 years. Female and male patients are equally involved in the age group below 60 years. After 60 years, Merkel cell carcinomas are more often observed in female patients. The tumor is most often located in the head and neck region (50.8%) or the extremities (33.7%). The average size is 29 mm at presentation. Clinically, only a presumptive diagnosis of Merkel cell carcinoma can be established. The definite diagnosis is made by histological, especially immunohistological methods (detection of intermediate filaments and neuroendocrine markers). The therapy of choice is local excision. Secondary therapy may be a combination of operation and radiation or chemotherapy. Since this combination may reduce the risk of recurrences it should be applied for patients with poor prognostic features. Especially in young patients, additional lymphadenectomy should be discussed. Clinical control is necessary. Distant metastases should be treated by chemotherapy. Bad prognostic features are: lymph node metastasis, size larger than 2 cm, male sex.