• Pathology of hidradenitis suppurativa;
  • one disease becomes two;
  • horny cell inflammation;
  • apocrinitis

Fismen S, Ingvarsson G, Moseng D, Dufour ND, Jørgensen L. A clinical-pathological review of hidradenitis suppurativa: Using immunohistochemistry one disease becomes two. APMIS 2012; 120: 433–40.

We report the results of a re-examination of a series of 57 biopsies from 50 patients with the clinical diagnosis of hidradenitis suppurativa, submitted to the Department of Pathology at the University Hospital of Northern Norway, Tromsø, Norway. The biopsy material came from hospitals and physicians all over northern Norway in the years 2000–2007. All tissue material was resectioned and stained with the immunohistochemical reagent, cytokeratin (AE1/AE3/PKC26), and that made it possible to divide the material into two different disease categories: (1) 36 biopsies from 30 cases had tissue inflammation after rupture of keratin-rich epidermal cysts, which we call ‘horny cell inflammation’, followed by extensive cutaneous thrombi and infarcts, and (2) 21 biopsies from 20 cases had ‘apocrinitis’ defined here as an inflammatory destruction of apocrine skin glands, and partly of close eccrine glands. The two disease populations differed: the patients with a diagnosis of horny cell inflammation were younger and mainly women; those with a diagnosis of apocrinitis, as defined here, were older, men and women equally represented.