Journal of Clinical & Experimental Dermatology Research
Open Access

Abstract

Pigmented Nevus

Keiji Sugiura and Mariko Sugiura

Background: Pigmented nevi develop at approx. 6 months after birth, and the number of pigmented nevi often increases until middle age. Pigmented nevi evolve with age and finally disappear.
Materials and methods: We studied 300 nevi of 78 male and 222 female Japanese patients. We analyzed the patients’ histopathological findings, the locations of their nevi, and their gender and age. We divided the nevi into three groups (1. all three histopathological-group, 2. junctional and compound group, 3. compound and intradermal group) based on their locations and pathological findings. Sun-exposed areas were the head, face, neck, limbs and hands. Other areas were classified as the non-sun-exposed areas.
Results: There were 41 junctional nevi, 73 compound nevi, and 186 intradermal nevi. The number of pigmented nevi peaked at middle age. The average age of the patients with intradermal nevi was significantly (P<0.05) older than those of the patients with junctional or compound nevi. The peaks in the numbers of junctional (30’s) and compound nevi (20’s) were lower than that of intradermal nevi. All three histopathologicalgroups were observed on the face and back. The junctional and compound nevi groups were observed on the hands, feet and soles. The compound and intradermal nevi groups were observed at the head, neck, chest, upper limb, abdomen, lumbar and buttock.
The face had the largest number of compound nevi and intradermal nevi; 28 and 93 cases, respectively. Junctional nevi were observed more commonly in the non-sun-exposed areas compared to the sun-exposed areas, whereas for the compound and intradermal nevi, the number of nevi at the sun-exposed areas was larger than that in the non-sun-exposed areas. The number of nevi arising at sun-exposed areas was greater than that at non-sunexposed areas in all generations.
Conclusions: Pigmented nevi often appear as junctional nevi and then migrate or evolve with age.