Transient complete remission of metastasized Merkel cell carcinoma by high-dose polychemotherapy and autologous peripheral blood stem cell transplantation.

Merkel cell carcinoma (MCC) is a rare cutaneous tumour with neuroendocrine differentiation. Metastasis occurs preferentially to regional lymph nodes but distant and multiple visceral metastases may occur. Chemotherapy has been performed with a variety of protocols based largely on agents active in small-cell lung cancer. Owing to the rarity of MCC, there is no standard protocol for the treatment of metastatic disease. We report a 59-year-old patient with systemic metastatic MCC. After diagnosis of distant metastases, first-line polychemotherapy (cisplatin 80 mg m(-2), doxorubicin 50 mg m(-2), etoposide 300 mg m(-2) and bleomycin 30 mg) was administered four times at 3-weekly intervals and resulted in partial remission of metastases. Subsequently, high-dose chemotherapy according to the PEI regimen (ifosfamide 12 g m(-2), carboplatin 900 mg m(-2) and etoposide 1500 mg m(-2)) was applied, followed by autologous blood stem cell transplantation (ABSCT). This protocol resulted in a complete remission that lasted for 6 months. This is the first report on a complete remission of metastatic MCC after high-dose polychemotherapy and ABSCT. High-dose chemotherapy might be a therapeutic option in chemosensitive metastatic MCC, and further evaluation is warranted.