title: Pathophysiology of merkel cell.
abstract: The objective of this review is to introduce Merkel cells (MCs), to provide a basic overview on the theoretical background of function, development and clinical importance of MCs. The origin of human MCs have been controversial. Some investigators believe that it is a neural crest derivate, whereas others have proposed that it is a differentiation product of the fetal epidermal keratinocytes. MCs are cells primarily localized in the epidermal basal layer of vertebrates and concentrated in touch-sensitive areas in glabrous, hairy skin and in some mucosa. In routine light microscopy, human MCs can hardly be identified. Cytokeratin 20 (CK20) is a reliable marker with highest degree of specificity. MCs can be also distinguished by electron microscopy. MC carcinoma (MCC) is an uncommon and often aggressive malignancy and found mainly in elderly patients. It occurs most frequently in the head and neck region. Diagnosis is based on typical histological presentation on hematoxylin and eosin (H and E) stained slides together with the results of immunohistochemistry. Histologically, MCC has been classified into three distinct subtypes: Trabecular, intermediate and small cell type.
authors.affiliation: Departments of Oral and Maxillofacial Pathology, Vidya Shikshan Prasarak Mandal's Dental college and Research Centre, Nagpur, Maharashtra, India.
authors.forename: Prashant Balasaheb
authors.initials: PB
authors.lastname: Munde
authors.affiliation: Departments of Oral and Maxillofacial Pathology, Vidya Shikshan Prasarak Mandal's Dental college and Research Centre, Nagpur, Maharashtra, India.
authors.forename: Shubhangi P
authors.initials: SP
authors.lastname: Khandekar
authors.affiliation: Departments of Oral and Maxillofacial Pathology, Vidya Shikshan Prasarak Mandal's Dental college and Research Centre, Nagpur, Maharashtra, India.
authors.forename: Alka M
authors.initials: AM
authors.lastname: Dive
authors.affiliation: Departments of Oral and Maxillofacial Pathology, Vidya Shikshan Prasarak Mandal's Dental college and Research Centre, Nagpur, Maharashtra, India.
authors.forename: Aparna
authors.initials: A
authors.lastname: Sharma
keywords: Cytokeratin 20; merkel cell carcinoma; merkel cells