Extracellular Granular Material and Degeneration of Keratinocytes in the Normally Pigmented Epidermis of Patients with Vitiligo

Abstract

Multiple biopsy specimens from the skin of 28 patients with common vitiligo were examined by light and electron microscopy. The patients were grouped according to the activity of their disease: progressing, stable, repigmenting, and resistant to treatment with psoralen plus sunlight. Three biopsy sites were sampled from each patient: (W) a white spot; (I) the pigmented and white interface; and (P) normally pigmented skin 1-15 cm away from I. Control specimens were obtained from 17 persons without vitiligo. Two microscopic abnormalities were observed in the epidermis of the patients with vitiligo: deposits of extracellular granular material, and foci of vacuolar degeneration of basal and parabasal keratinocytes. The extracellular granular material appeared to be derived from the cytoplasm of vacuolated keratinocytes. The abnormalities were observed in greatest abundance in the normally pigmented skin of patients with rapidly progressing or stable disease. They were absent from repigmenting skin and from the skin of healthy controls. Epidermal infiltrates of mononuclear leukocytes were seen only in the normal pigmented skin of the 2 patients whose vitiligo was resistant to treatment. Our observations indicate that cellular degeneration and the generation of debris in vitiligo are not limited to melanocytes but include keratinocytes and probably whole epidermal melanin units. Our findings also indicate that the fine structure of the epidermis in normal-appearing skin is markedly altered by the disease process in patients with vitiligo.

A Critical Appraisal of Vitiligo Etiologic Theories. Is Melanocyte Loss a Melanocytorrhagy?

“…It has emerged as one of the most debated in the last decade. The vacuolation and degenerative changes noted in NSV skin could be the expression of oxidative damage (51,52). Low catalase activity leading to epidermal accumulation of H 2 O 2 has been demonstrated in non-lesional and in lesional NSV skin (53) and in cultured melanocytes (54,55).…”

Association of the Köbner Phenomenon With Disease Activity and Therapeutic Responsiveness in Vitiligo Vulgaris

“…The definitions for either active or stable vitiligo seem to be different for different clinicians. According to Moellmann et al, 17 active vitiligo is the clinical stage "when lesions are enlarging in the 6 weeks" before examination, whereas, according to Cui et al, 18 active vitiligo is "the development of new lesions or extension of old lesions in the 3 months before the first consultation." Other clinicians, such as Uda et al, 19 define active vitiligo when the lesions are reported to "spread without regression within the last half year."…”

Focus on Vitiligo: A Generalized Skin Disorder

“…Carbohydrate degradation may in tum give rise to various genotoxic and cytotoxic compounds which may amplify the initial injury caused by HP2-derived ROS, possibly leading to apoptosis (36). The vacuolation and degenerative changes already described in the epidermis of active NSV may be the expression of oxidative damage (37).…”