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Histogenesis of pure and combined Merkel cell carcinomas: An immunohistochemical study of 14 cases
Author(s) -
Narisawa Yutaka,
Koba Shinichi,
Inoue Takuya,
Nagase Kotaro
Publication year - 2015
Publication title -
the journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 65
eISSN - 1346-8138
pISSN - 0385-2407
DOI - 10.1111/1346-8138.12808
Subject(s) - histogenesis , merkel cell , hair follicle , cytokeratin , stem cell , pathology , biology , merkel cell carcinoma , stem cell marker , immunohistochemistry , carcinoma , microbiology and biotechnology , medicine
The histogenesis of Merkel cell carcinoma ( MCC ) has remained unresolved. Moreover, one of the questions is whether pure MCC and combined MCC represent the same histogenesis and entity. The existence of combined MCC suggests that MCC likely arise from pluripotent stem cells. Merkel cells ( MC ) localize within the bulge area, which is populated by hair follicle stem cells. We used hair follicle stem cell markers to investigate whether MCC share certain characteristics of these stem cells. Fourteen MCC specimens were examined histologically and immunohistochemically. There were six pure MCC and eight combined MCC . In six combined MCC , both MCC components and squamous components at least focally shared the expression of one or more of cytokeratin ( CK )15, CK 19 and CD 200, which are hair follicle stem cell markers. On the other hand, four cases of pure MCC showed partially distinct CK 19 expression, but did not show CK 15 and/or CD 200 expression. There was a distinct difference between pure MCC and combined MCC on the expression of hair follicle stem cell markers. The normal skin expressed CK 15, CK 19 and CD 200 in the bulge area, whereas CK 15 and CD 200 were absent in the MC ‐rich glabrous skin and touch domes. The results led us to hypothesize that combined MCC originate from the hair follicle stem cells. We postulate that combined MCC undergo multidirectional differentiation into squamous, glandular, mesenchymal and Merkel cells. Further investigation is warranted to confirm the histogenesis of pure MCC and combined MCC .