Oral hairy leukoplakia. A distinctive marker of human T-cell lymphotropic virus type III (HTLV-III) infection.

Oral hairy leukoplakia (HL) is a newly described lesion occurring principally on the lateral borders of the tongue in immunosuppressed homosexual men infected with human T-cell lymphotropic virus type III (HTLV-III). Clinically, HL appears as a slightly raised, poorly demarcated lesion with a corrugated or "hairy" surface. Histologically, the lesion is characterized by keratin projections on the surface (which often resemble hairs), parakeratosis, and acanthosis. In addition, large pale-staining cells with pyknotic nuclei are seen in the upper stratum malpighii, which appear similar to the koilocytes described in uterine condylomata. Candida organisms are frequently observed on the lesion surface. Little, if any, subepithelial inflammation is present. Human papillomavirus and Epstein-Barr virus have been identified in biopsy specimens from lesions of oral HL. The association of this lesion in patients with HTLV-III infection has been established. We saw a patient with HTLV-III infection and HL, in whom the immunochemical and ultrastructural findings revealed the presence of a mixed viral infection. Because oral HL may be of diagnostic value as an early indicator of HTLV-III infection, awareness of its characteristic clinical, histologic, immunochemical, and ultrastructural features is important.