H. Kurzen et al., Forms of epithelial differentiation of draining sinus in acne inversa (hidradenitis suppurativa), BR J DERM, 141(2), 1999, pp. 231-239
The draining sinus is a late complication of several forms of severe acne,
leading to extensive, periodically inflamed lesions that are undermined by
a system of fistulas, supposed to be of follicular origin. We investigated
the expression of various cytokeratins (CKs) and desmosomal proteins in the
draining sinus of acne inversa (hidradenitis suppurativa) using monoclonal
antibodies in immunohistochemistry on paraffin-embedded sections. We were
able to define three different phenotypes of stratified squamous epithelia
covering the sinus tracts. Type I epithelium was cornifying and characteriz
ed by the presence of CK 10, desmogleins 1-3 and desmocollins 1-3 in an epi
dermis-like pattern. Type II epithelium was non-cornifying, negative for CK
10 and positive for CK 13, It was negative for desmocollin 1 but strongly
immunopositive for desmoglein 1 suprabasally and for desmoglein 2 in the ba
sal cells. Type LII epithelium was non-cornifying and strongly inflamed. It
was marked by the presence of CK 7, CK 19 and desmoglein 2 and the absence
of CK 10, desmoglein 1 and desmocollin 1. In both type II and III epitheli
um, desmoglein 3, desmocollin 2 and desmocollin 3 showed an inverted staini
ng pattern as compared with normal epidermis and type I epithelium. Desmogl
ein 2 and CIC 5/14 always remained restricted to the basal cell layer. Anti
bodies against CK 6 and CK 13/15/16 were immunopositive in all three phenot
ypes and CK 17 was predominantly immunolocalized to suprabasal layers of ty
pe II and III epithelium. The three phenotypes are characterized as patholo
gical stratified squamous epithelia reflecting the dynamic process of infla
mmation, proliferation and stratification taking place in acne inversa.