A rare case of cutaneous acanthamoebiasis in a renal transplant patient

Abstract

A 35-year-old woman receiving immunosuppressionfor renal transplantation presented with a onemonthhistory of tender skin nodules on herbilateral upper extremities. A skin biopsy revealedgranulomatous inflammation in the deep dermisand the subcutaneous fat with foci of necrosis.Within the foci of necrosis were large histiocytoidstructures with prominent nuclei. Periodic acid-Schiffstain revealed a round organism with a thick capsule,consistent with amoebal trophozoites. Testing withthe Center for Disease Control revealed the organismto be Acanthamoeba. Despite antimicrobial therapy,the patient continued to develop subcutaneousnodules that extended to the lower extremities andtrunk and ultimately extended to the bone, causingacanthamoebal osteomyelitis. Throughout thehospital course, the patient remained neurologicallyintact without evidence of central nervousinvolvement. A diagnosis of isolated disseminatedcutaneous acanthamoebiasis secondary to iatrogenicimmunosuppression was made. Historically, mostcases of granulomatous amoebic encephalitisand cutaneous acanthamoebiasis have occurredin patients with HIV/AIDS. However, with the useof newer and more effective immunosuppressiveregimens, both are occurring more frequently inthe setting of iatrogenic immunosuppression. Therare and isolated cutaneous nature of this patient'spresentation makes this case unique.