1994 Volume 35 Issue 1 Pages 69-73
The agar implantation method allows observation of the parasitic form of a fungus by intraperitoneally implanting agar blocks inoculated with the fungus into mice. In the present study, we adapted this method by implanting agar blocks intradermally in mice to observe transepidermal elimination in chromomycosis. Agar blocks containing the fungal elements of Foncecaea pedrosoi were implanted intradermally into the backs of C57BL/6 mice, and the areas of skin including the agar blocks were sequentially harvested and examined histologically. Infiltration of polymorphonuclear leukocytes and lymphocytes was seen around the agar blocks at 2 weeks after implantation. After 4 weeks, histiocytes and epithelioid cells appeared and a pyogenic granuloma formed. At the same time, pseudocarcinomatous hyperplasia of the epidermal processes overlying the agar block was seen. From 6 weeks onwards, the epidermal processes which surrounded the infiltrating cells became longer, and microabscesses partially surrounded by these elongated processes were noted as well as transepidermal elimination of agar containing hyphae. These results suggest that intradermal agar implantation is a useful method for the sequential observation of early infection and transepidermal elimination in chromomycosis.
