This study was performed to determine if, in whites, different states of hyperpigmentation exhibit different distribution patterns of melanosomes; if melanosome size influences the distribution of melanosomes; and if melanosome distribution correlates with the degree of pigmentation. It was found by electron microscopic investigations that (1) the distribution patterns of melanosomes vary in different hyperpigmentary states; (2) there is a striking tendency for small melanosomes to be complexed and for large ones to be dispersed as singles; and (3) in whites, there is no definite relationship between the degree of pigmentation and the distribution pattern of melanosomes. Hence, the size of melanosomes determines the distribution pattern but the distribution pattern alone does not correlate with the intensity of pigmentation.
Konrad K, Wolff K. Hyperpigmentation, Melanosome Size, and Distribution Patterns of Melanosomes. Arch Dermatol. 1973;107(6):853-860. doi:10.1001/archderm.1973.01620210021005