A case of extramammary Paget's disease with depigmented macules as the sole manifestation.

We report a 76-year-old man who had four depigmented macules in the genital area as the sole manifestation of extramammary Paget's disease (EMP). Histologically, many scattered, dissociated, plump Paget cells, and small intraepidermal nests of these cells were seen in all four lesions. The distribution of Paget cells extended beyond the margin of the depigmented areas into adjacent normally pigmented skin. Fontana-Masson staining revealed a reduction in, or absence of, melanin deposition along the basal layer of the depigmented lesions, in contrast with an abundance of melanin along the basal layer of the adjacent normal skin. Pigment-blockade melanocytes and melanophages were seen within or below the affected epidermis. The depigmentation in this case could have been caused by a symbiotic disorder between melanocytes and keratinocytes (including melanocyte destruction), and by a disorder in melanosome transmission to the keratinocytes. This case illustrates that a depigmented macule may be a diagnostic feature of EMP. Moreover, depigmentation is probably one of the earliest clinical features of EMP, and not a neighbouring secondary change such as occurs in the Sutton's halo naevus phenomenon.