Idiopathic guttate hypomelanosis: an electron microscopy study.

BACKGROUND

Few published data, concerning the electron microscopy findings of idiopathic guttate hypomelanosis have been published so far.

OBJECTIVES

To reveal the electron microscopic findings of idiopathic guttate hypomelanosis and their aetiopathogenetic associations.

METHODS

Punch biopsy specimens from four patients with idiopathic guttate hypomelanosis, after being properly processed, were observed under the electron microscope.

RESULTS

In the epidermis, melanocytes and melanosomes were normal in structure. In some areas, there was a reduced uptake of melanosomes by the keratinocytes. In the dermis, fibroblasts were structurally normal. Also, most elastic and collagen fibres were normal, but there were focal elastotic changes.

CONCLUSIONS

No significant structural abnormality of the melanocytes was observed, but rather a functional defect in the transfer of melanosomes from the melanocytes to the keratinocytes.