Tinea versicolor: a light and electron microscopic study of hyperpigmented skin.

Hyperpigmentation in lesions of tinea versicolor has previously been reported to be a result of the effects of the fungus Pityrosporon orbiculare on melanosome formation and distribution. Examination of biopsy specimens from lesions of hyperpigmented tinea versicolor involving vitiliginous skin reveals an absence of melanosomes and melanocytes. Reddish-tan and fawn-colored hyperpigmentation in tinea versicolor of this type is not due to melanin pigment. The possible nature of the pigmentation that delineates hyperpigmented tinea versicolor from normal skin is discussed.