Cytokeratins as Markers of Follicular Differentiation

December 2001 in “ American Journal of Dermatopathology ”

Hjalmar Kurzen, Lorenz Esposito, Lutz Langbein, Wolfgang Hartschuh

cytokeratins trichoblastoma basal cell carcinoma CK6hf CK14 CK17 CK15 CK19 CK8 Merkel cells outer root sheath epithelium companion layer inner root sheath

Studysummary This study found that trichoblastomas and nodular basal cell carcinomas have similar cytokeratin expression patterns, indicating differentiation towards the outer root sheath epithelium.

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The study investigated the expression of cytokeratins in trichoblastoma (TB) and basal cell carcinoma (BCC) to understand their differentiation towards hair follicle structures. Both TB and BCC consistently expressed CK6hf, CK14, and CK17, indicating differentiation towards the outer root sheath epithelium or companion layer. CK15 and CK19 showed variable expression, with 38% of TB and none of the BCC expressing CK15, while 70% of TB and 22% of BCC expressed CK19. CK8 was found in Merkel cells in all TB but not in BCC. No hair keratins were expressed in either tumor type, suggesting a lack of differentiation towards the inner root sheath, matrix, or cortex.

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