Primary cicatricial alopecias: a review of histopathologic findings in 38 patients from a clinical university hospital in Sao Paulo, Brazil.

Background: Scarring alopecias are classified into primary and secondary types according to the initial site of inflammation. In primary scarring alopecias, the hair follicle is the main target of destruction; the term secondary cicatricial alopecia implies that follicular destruction is not the primary pathologic event.

Aims: To review the histopathologic diagnoses of cases of cicatricial alopecia in order to classify them according to the North American Hair Research Society.

Patients And Methods: Patients with biopsy specimens diagnosed as cicatricial alopecia seen from 2000 to 2005 at the Dermatologic Department of Hospital das Clinicas, São Paulo University Medical School had hematoxylin and eosin, Periodic acid-Schiff and Weigert stained slides reevaluated and sub-typed into different primary cicatricial alopecias.

Results: Thirty-eight cases of primary cicatricial alopecias were reclassified as: chronic cutaneous lupus (17), lichen planus pilaris (4), pseudopelade of Brocq (12), folliculitis decalvans (3), dissecting folliculitis (1), and non-specific scarring alopecia (1). In our cases, the methods employed allowed an accurate diagnosis in 12 of 13 cases (92.3%) previously classified as non-specific cicatricial alopecias.

Conclusions: Even in the late, pauci or non-inflammatory phases, an approach with systematic evaluation of a constellation of criteria in routine hematoxylin and eosin stain, Periodic acid-Schiff and Weigert stain allowed for a more accurate diagnosis of cicatricial alopecias.