Merkel cell carcinoma as rare malignant skin tumor (two clinical cases)

Abstract

This article provides a review of the literature on the prevalence of Merkel carcinoma, the features of its clinical, dermoscopic, pathomorphological diagnosis and therapy. In the light of the presented data, two of our own clinical observations of Merkel carcinoma are described: a clinical and dermoscopic description, a pathomorphological and immunohistochemical picture, the treatment performed and its long-term results are given. In the presented clinical observations, Merkel carcinoma was detected in two women aged 70 and 83 years at stage I, which determined a favorable prognosis. Clinically, the tumor was presented in the form of a dense, non-ulcerated nodule or a pink-red nodule; all neoplasms were localized on the head. The dermoscopic picture was different, in one case it was represented by globules and dots of red color against a background of milky pink and white areas, individual linear and convoluted vessels, there were white structures (like chrysalids), and in another case – structureless areas of pink color with tree-like vessels and white structures in the form of chrysalids. Histologically, the small round cell type of structure predominated. An IHC study in both cases revealed a pronounced expression of cytokeratin 20 and chromogranin A, the Ki‑67 index was above 70 %.