Solid basal cell epithelioma (BCE) possibly originates from the outer root sheath of the hair follicle

The presence and distribution of several cytokeratins (CKs) in 20 solid basal cell epitheliomas (BCEs) were investigated and compared with the pattern of CKs in normal epidermis, perilesional skin and in the outer root sheath (ORS) of the human hair follicle. Tissue samples were stained with monoclonal antibodies (MoAbs) against human CKs, using the APAAP technique. Additionally, CK profiles were assessed by gel electrophoresis and immunoblot technique. Cells of BCE and ORS were positively stained with the MoAb KL1, wheareas teh basal layer of normal epidermis remained negative