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May 10, 1965


JAMA. 1965;192(6):567-568. doi:10.1001/jama.1965.03080190133029

The melanocyte is a secretory cell which synthesizes melanin granules in a symbiotic relationship with the keratinocyte, the remaining cellular component of the human epidermis. Melanocytes undergo numerous and diverse functional and neoplastic changes. Electron microscopy and gradient biochemistry indicate that melanin biosynthesis proceeds in specific cytoplasmic organelles, melanosomes, formed by the Golgi apparatus under genetic influences. Tyrosinase is thought to be synthesized by ribosomes and then transferred to the melanosomes which proceed to melanization. Macromolecular characterization and differentiation of various pigmentary diseases is presented in the May issue of the Archives of Dermatology.1 Evidence is offered that melanosomes are not only under genetic control but also show specific polymorphism according to various disease states.

The clinical significance of the distinct morphological differences of melanosomes is evidenced in a comparison of melanotic malignant melanoma and intradermal nevus cells. The differential diagnosis of these conditions is often difficult, in spite