Summary

Merkel cell carcinoma is a skin tumor with poor prognosis that may pose differential diagnostic problems with some primary skin tumors as well as metastatic ones. In this report, 5 Merkel cell carcinoma cases were evaluated regarding their clinical and histopathologic findings. Three patients were women and two were men. The mean age was 57,4 (range: 26-79). Tumor size range was 1-13 cm. Positivity for immunohistochemical markers were 5/5 for pancytokeratin, 5/5 for cytokeratin 20, 0/5 for cytokeratin 7, 4/5 for neuron specific enolase, 3/5 for chromogranin and 3/5 for synaptophysin. Dot-like, crescentic or signet-ring type staining patterns were seen for cytokeratin 20. The same pattern was also observed for pancytokeratin, chromogranin and synaptophysin. Three cases were died of their tumor following 10, 24 and 28 months after the initial excision. One of the cases was alive after 26 months, and the last one was lost to follow-up.