Light and Electron Microscopic Study of Riehl's Melanosis. Possible Mode of its Pigmentary Incontinence

Abstract

Four cases of Riehl's melanosis were studied with light and electron microscopes. The results obtained were as follows: Unmyelinated nerve fibers were found in both the epidermis and the dermis, and the Schwann cells enclsing the axons contained melanosomes. A peculiar pigment cell was found in the epidermis, it was thought to be a macrophage phagocytizing melanosomes from the extracellular spaces. A melanophage in contact with a keratinocyte through the gaps of the basal lamina was observed. It was suggested that all these processes might participate in pigmentary incontinence in Riehl's melanosis. At the dermo‐epidermal junction the basal lamina was multilayered. In the upper dermis a large number of melanophages were present, and in addition, amyloid islets and fibrillar masses resembling the “fibrilläre Körper” were observed.

Miz1 is required for hair follicle structure and hair morphogenesis

“…This is confirmed by the observation that melanin accumulates around hair follicles in the dermis with aging (Fig. 5F), which is probably due to a poorly defined process known as pigmentary incontinence described in inflammatory skin diseases (Schaumberg-Lever and Lever, 1973;Nagao and Iljima, 1974;Masu and Seiji, 1983) and in senile lentigo (Ünver et al, 2006). In addition, mice.…”

Electron Microscopic Studies on Civatte Body in Riehl's Melanosis

“…Amyloid-like filament masses which could not be differentiated from the true amyloid in PLCA were observed in four patients. While amyloid stainings such as congo red and thioflavin T stains were entirely negative in our cases, Nagao and Iijima (1974) reported that thioflavin T-positive amyloid were found in their cases of Riehl's melanosis. And it is known in general that the tinctorial properties of amyloid are not always consistent (Nakagawa 1965;Rook et al 1972).…”

“…They speculated that Civatte bodies might be converted into amyloid or in some way provide a matrix for the formation of amyloid. In Riehl's melanosis, Nagao and Iijima (1974) found Civatte bodies and amyloid, and suggested that these two substances were pathogenetically related. Recently, a case with lichen amyloidosus on the legs and Riehl's melanosis-like lesion on the face was studied under the electron microscope, and it was concluded that Civatte bodies could be converted into amyloid under certain conditions like Riehl's melanos is because it was found that there were transitional forms between Civatte body and amyloid in the skin specimen from the face (Masu et al 1979).…”

Melasma on the Nape of the Neck in a Man

“…Riehl's melanosis typically involves the face with a brownish-grey pigmentation; biopsy might be expected to show interface change and liquefaction basal cell degeneration with a moderate lymphohistiocytic infiltrate, melanophages and pigmentary incontinence in the upper dermis. It is usually associated with cosmetic use and may be considered synonymous with pigmented allergic contact dermatitis of the face (6,7). Berloque dermatitis is considered to be caused by a photoirritant reaction to bergapentin; it may affect the sun-exposed areas of the face, neck and arms.…”