A rare case of cutaneous acanthamoebiasis in a renal transplant patient

A 35-year-old woman receiving immunosuppression for renal transplantation presented with a one-month history of tender skin nodules on her bilateral upper extremities. A skin biopsy revealed granulomatous inflammation in the deep dermis and the subcutaneous fat with foci of necrosis. Within the foci of necrosis were large histiocytoid structures with prominent nuclei. Periodic acid-Schiff stain revealed a round organism with a thick capsule, consistent with amoebal trophozoites. Testing with the Center for Disease Control revealed the organism to be Acanthamoeba. Despite antimicrobial therapy, the patient continued to develop subcutaneous nodules that extended to the lower extremities and trunk and ultimately extended to the bone, causing acanthamoebal osteomyelitis. Throughout the hospital course, the patient remained neurologically intact without evidence of central nervous involvement. A diagnosis of isolated disseminated cutaneous acanthamoebiasis secondary to iatrogenic immunosuppression was made. Historically, most cases of granulomatous amoebic encephalitis and cutaneous acanthamoebiasis have occurred in patients with HIV/AIDS. However, with the use of newer and more effective immunosuppressive regimens, both are occurring more frequently in the setting of iatrogenic immunosuppression. The rare and isolated cutaneous nature of this patient’s presentation makes this case unique.