Nearly 10% of Japanese people have pigmented nevi on the soles. Since malignant melanoma also occurs on the plantar area in the Japanese, it would be very valuable to be able to differentiate benign and malignant lesions in the early clinical state. We have investigated the epiluminescence microscopic features of 500 melanocytic nevi on the soles of Japanese people using a dermatoscope and a videomicroscope that can magnify lesions from x 10 to x 200. The results showed that the surface profile of benign melanocytic nevi is mainly classified into five types; that 9% of plantar nevi, however, do not fit into this classification and are categorized as a miscellaneous type; and that the other nonmelanocytic disorders, such as verruca vulgaris and black heel, are easily differentiated by their surface profile. More important, the histological examination showed that atypical nevi, malignant melanoma in situ, and acral lentiginous melanoma are exclusively compartmentalized in the miscellaneous type of surface profile. Our data suggested that epiluminescence microscopy may be a useful method for discrimination of plantar benign and malignant melanocytic lesions.
Langerhans cells are MHC class II (Ia) positive antigen-presenting cells that play a crucial role in the induction of contact hypersensitivity (CHS). The topical application of a hapten modifies the cell surface moieties of Langerhans cells, and activates Langerhans cells to increase their size and Ia intensity. The haptenated and activated Langerhans cells emigrate from the epidermis and thus the in situ density of Langerhans cells usually decreases during 24-48 h after the hapten application in CHS. To determine whether the early activation pattern of Langerhans cells is different between the afferent phase and the efferent phase of CHS, we compared the density and morphologic changes of Langerhans cells in CHS to trinitrochlorobenzene using nonsensitized and sensitized mice. We found that the application of a hapten induces more significant enlargement of Langerhans cell size in the afferent phase than in the efferent phase, whereas the reduction of Langerhans cell density is more marked in the efferent than in the afferent phase of CHS. Moreover, topical immunosuppressive drugs inhibit the in situ activation of Langerhans cells.
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