Clinical and histologic spectrum of oral hairy leukoplakia.

Oral hairy leukoplakia (HL) is a frequent, apparently specific, and early clinical sign of exposure to human immunodeficiency virus. We studied 50 consecutive patients, or whom two had acquired immune deficiency syndrome (AIDS) at the time of diagnosis of HL. AIDS developed in another eight patients during the observation period. All patients had HL on the lateral portion of the tongue, most often evident as bilateral white lesions with a corrugated surface. The size, severity, and surface characteristics of the lesions showed wide variation. Clinically flat lesions, most often located on the ventral surface of the tongue, also occurred in one third of the cases. The dominant histologic features were epithelial hyperparakeratosis with hairlike projections, hyperplasia/acanthosis, vacuolated cells resembling koilocytes, and an absence of inflammation in the connective tissue. In addition, candidal hyphae and bacteria were often seen in or on the surface epithelium. Lesions that were flat clinically often lacked "hairs" histologically. There was no correlation between clinical size, severity, or surface characteristics and the development of AIDS. Similarly, no histologic parameters identified subgroups of patients as being at a higher risk for the development of AIDS. Thus, even the most subtle white lesion of the tongue may indicate a considerable risk for the later development of AIDS. It can be concluded that HL represents a new lesion, predominantly of the tongue, in patients with HIV infection that shows considerable clinical and histologic variation. Typical HL is easily diagnosed, but atypical HL may be diagnosed mostly on the basis of absence of response to antifungal treatment and histologic exclusion of other lesions.