[Merkel cell carcinoma]

Merkel cell carcinoma is a rare aggressive malignant neuroendocrine skin tumor, which can metastasize to lymph nodes early and often shows local recurrence. The prognosis depends on tumor size and disease stage. The majority of recurrences appear during the first 2 years after the primary diagnosis. The 5-year survival rate for primary tumor < 2 cm is 66-75 % and for primary tumors > 2 cm is 50-60 %. With lymph node metastases the 5-year survival rate is 42-52 %, while with distant metastases it drops to 17-12 %. Extensive staging inclusive sentinel lymph node biopsy is essential to assess the risk for distant metastasis and to allow the best recommendations for therapy. After surgical treatment with adequate safety margin, subsequent adjuvant radiation therapy of the tumor region and lymphatic draining basin is recommended to reduce the risk of local recurrence and lymphatic spread.