Merkel cell carcinoma: literature review

Abstract

Merkel cell carcinoma (MCC) was given a such name after the German histopathologist Friedrich Merkel, who first in 1875, described the Merkel cells, as small round or oval basophilic cells located at the end of nerve axons and within the basal layer of the epidermis. The current agreement about the function of Merkel cells they are associated with the nerve terminals acting as mechanoreceptors. MCC is a clinically aggressive uncommon, cutaneous neuroendocrine neoplastic tumour with a high mortality rate. Clinically may be presented as a painless, rapidly growing, dome-shaped red or purplish nodule. Usually in a sun-exposed area of the head and neck or upper limbs. Tremendous effort has been done in the last few years for a better understanding of the pathogenesis behind the MCC and the discovery of the Merkel cell polyomavirus suggests another clue to its pathogenesis. The expression of both epithelial and neuroendocrine immunohistochemical markers in the malignant cells, gives the tumour a unique feature that helps differentiate this neoplasm from other entities.