Dermal melanocytosis in Japanese monkeys (Macaca fuscata)

Area of Science:

• Dermatology
• Comparative Pathology
• Primate Biology

Background:

• Japanese monkeys (Macaca fuscata) display skin discolorations resembling human dermal melanocytosis.
• Dermal melanocytes are rare in laboratory animals, making Macaca fuscata unique.

Purpose of the Study:

• To characterize the dermatologic features of Japanese monkeys.
• To investigate gross appearance, skin color, and histopathology.
• To assess Macaca fuscata as a model for dermal melanogenesis.

Main Methods:

• Colorimetric analysis of pigmented and nonpigmented skin sites.
• Histopathological examination of tissue specimens.
• Utilized Yxy, L*a*b*, and L*C*h* color systems.

Main Results:

• Significant colorimetric differences detected between pigmented and nonpigmented sites.
• Pigmented sites showed epidermal melanocyte absence but dermal melanocytes with abundant melanin.
• Nonpigmented sites lacked melanin in both epidermis and dermis.

Conclusions:

• Gross dermal melanocytosis in Japanese monkeys correlates with colorimetric and histopathological findings.
• Macaca fuscata pigmentation is analogous to human dermal melanocytosis.
• Japanese monkeys may serve as a valuable animal model for dermal melanogenesis research.