Ultrastructural study of vitiligo.

BACKGROUND: Vitiligo is a relatively common skin disease characterised by development of patchy depigmented macules. A comparative ultrastructural study was undertaken between early developing (2-6 months duration) and long standing (1-5 years duration) lesions of vitiligo in a series of ten patients. METHODS: Skin biopsy specimens from the ten patients were fixed, stained, and examined under an electron microscope. RESULTS: No melanocytes were found in the sections taken from long standing lesions. The sections from early lesions showed junctional melanocytes exhibiting various cellular abnormalities. The epidermal keratinocytes were normal in all sections; however, some sections from the periphery of early lesions exhibited minor degenerative changes. CONCLUSIONS: We can assume that because of the absence of melanocytes in long standing lesions, repigmentation may occur only from the melanocytic reservoir in the hair follicles. Repigmentation may also occur in lesions of short duration by reactivation of melanocytes present in the area, so an attempt should be made to treat vitiligo lesions in their early stage.

Malignant transformation of eccrine tumors.

Malignant transformation occurred in pre-existing sweat gland tumors in 7 patients. Three lesions showed an histologic pattern of eccrine spiradenoma, 2 eccrine poroma, one cylindroma and one papillary eccrine adenoma. Malignant transformation was histologically characterized by the presence of solid tumor areas populated with large cells having irregularly shaped nuclei and mitotic figures. There were multiple foci of squamous metaplasia, areas of loss of basement membrane and invasion of the surrounding connective tissue.