The changes in the expression levels of follicular markers in keratoacanthoma depend on the stage: keratoacanthoma is a follicular neoplasm exhibiting infundibular/isthmic differentiation without expression of CK15
Article first published online: 11 MAR 2014
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Journal of Cutaneous Pathology
Volume 41, Issue 5, pages 437–446, May 2014
How to Cite
The changes in the expression levels of follicular markers in keratoacanthoma depend on the stage: keratoacanthoma is a follicular neoplasm exhibiting infundibular/isthmic differentiation without expression of CK15., , , .
- Issue published online: 24 APR 2014
- Article first published online: 11 MAR 2014
- Accepted manuscript online: 12 FEB 2014 06:08AM EST
- Manuscript Accepted: 28 DEC 2013
- Manuscript Revised: 19 NOV 2013
- Manuscript Received: 12 FEB 2013
- bulge stem cells;
- follicular differentiation;
Although the precise etiology of keratoacanthoma (KA) is unknown, KA is generally assumed to differentiate toward hair follicles based on previous studies of experimental carcinogenesis.
We performed a comprehensive immunohistochemical study of various follicular markers in all stages of KA. A total of 67 tumors, including 16 early or proliferative stage lesions, 43 well-developed stage lesions, five regressing stage lesions and three regressed stage lesions, were subjected to the analysis.
CK15 (clone C8/144B), CK19 and CD34 were not expressed at any stage. CK1, CK10, CK16, CK17, CK15 (clone LHK15) and calretinin showed dynamic changes in their expression in KA depending on the stage.
KA is a follicular neoplasm with infundibular/isthmic (upper segmental region of hair follicles) differentiation. It is considered that early or proliferative stage tumors show keratin-filled invaginations with infundibular differentiation and gradual isthmic differentiation. Well-developed examples of KA generally show isthmic differentiation in the whole lesions. The regressed stage KAs lose the features of this type of follicular differentiation and show epidermal characteristics. No expression of CK15 (clone C8/144B) was observed in KAs, although this finding is insufficient to completely rule out the correlation between the regression of KA and the hair follicle cycle.