Cytokeratin expression in pseudoepitheliomatous hyperplasia of oral paracoccidioidomycosis.

Paracoccidioidomycosis (Pmycosis) is one the most prevalent deep systemic mycoses in Latin America. It is characterized by granulomatous inflammation and pseudoepitheliomatous hyperplasia. Cytokeratins (CKs) are a group of intermediate filaments of epithelial cells and their expression varies according to the epithelium type, differentiation and pathological processes. This study describes cytokeratin expression as examined by immunohistochemistry, in 28 cases of oral Pmycosis involving the buccal mucosa, lip, gingiva and hard palate. Expression of CKs in the basal layer of the epithelium in pseudoepitheliomatous hyperplasia of Pmycosis was similar to that in normal oral mucosa (NOM), but in Pmycosis CK1 and CK10 were not expressed in the spinous and superficial layers of the lip, gingiva or hard palate, and, in the spinous and superficial layers of the lip and buccal mucosa, CK14 was positive in contrast to NOM where it was negative. In Pmycosis, CK6 was more frequently expressed in the spinous layer of the lip, gingiva and hard palate, but nevertheless CK16 expression was decreased in the spinous and superficial layers of the gingiva and hard palate. We conclude that pseudoepitheliomatous hyperplasia in oral Pmycosis shows a different pattern of CK expression, particularly CKs 1, 10 and 14, compared with NOM.