Epidermal cysts in a tacrolimus treated renal transplant recipient.

Tacrolimus, a calcineurin inhibitor, formerly also known as FK506, is a macrolactam drug isolated from Streptomyces tsukubaensis. Its mode of action closely parallels the action of cyclosprorin A (CsA) and can be used for the treatment of inflammatory and autoimmune skin diseases in which systemic CsA has proved effective against psoriasis, pyoderma gangrenosum, atopic dermatitis, lupus erythematosus and graft versus host disease (GVHD). Although several cases of epidermal cysts have been reported in patients using cyclosporine and other immunosuppressants after organ transplantation; such types of cases have yet not been reported after administration of tacrolimus. However, we report herein a case of presence of multiple, various sized epidermal cysts in a renal transplant recipient receiving tacrolimus.