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Epithelial keratin and filaggrin expression in seborrheic keratosis: evaluation based on histopathological classification
Author(s) -
Yoshimi Nobuko,
Imai Yasutomo,
Kakuno Ayako,
Tsubura Airo,
Yamanishi Kiyofumi,
Kurokawa Ichiro
Publication year - 2014
Publication title -
international journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 93
eISSN - 1365-4632
pISSN - 0011-9059
DOI - 10.1111/j.1365-4632.2012.05828.x
Subject(s) - seborrheic keratosis , medicine , filaggrin , keratin , dermatology , keratosis , pathology , atopic dermatitis
Objectives Seborrheic keratosis ( SK ) is classified into six types: hyperkeratotic; acanthotic; irritated; clonal; reticulated; and adenoid. However, the origins of the respective types of SK remain unclear. Methods To clarify the histogenetic origins of SK , we performed immunohistochemical studies of keratin ( K ) and filaggrin expression, taking into account the histopathological classifications of SK . Results Hyperkeratotic SK mainly expressed K 1, K 10, and filaggrin. Acanthotic SK mainly expressed K 14 with some K 15. Irritated SK mainly expressed K 14 and K 17 in squamous eddies. Clonal SK , reticulated SK , and adenoid SK mainly expressed K 14. The results show that hyperkeratotic SK differentiated towards squamoid terminal keratinization, whereas acanthotic, irritated, clonal, reticulated, and adenoid SK mainly differentiated towards basaloid undifferentiated cells. In addition, acanthotic SK differentiated towards the hair bulge, and irritated SK differentiated towards the follicular infrainfundibulum. Conclusions Based on the patterns of keratin and filaggrin expression demonstrated by the histopathological types, SK demonstrated diverse differentiation towards epidermal keratinization, basaloid cells, the infrainfundibulum and hair follicle bulges, which suggests that SK is in an undifferentiated and hyperproliferative state with heterogeneous differentiation. The immunohistochemical method of investigating patterns of keratin expression is useful in the differential diagnosis of cutaneous epithelial tumors.