Giant melanin granules in vitiliginous achromia with malignant melanoma.

Histological and ultrastructural examination of normal and perilesional skin of a patient with vitiliginous depigmentation associated with a malignant melanoma revealed the presence of giant melanin granules in keratinocytes and melanocytes. These structures are compared to macromelanosomes which have been observed in numerous pigmentary diseases. The formation and significance of the giant melanin granules is discussed.