Cutaneous protothecosis: A case report and review of the literature

Protothecosis is a rare cause of systemic and/ or cutaneous infection. Because approximately 100 cases of human infection with Prototheca wickerhami have been reported, little is known about the pathogenesis of this infection. Cases include both immunocompetent and immunocom-promised patients. However, most cases contain an element of immune compromise, either local or systemic. We present a case of an 81-year-old white woman with a history of multiple nonmelanoma skin cancers, including squamous and basal cell carcinomas and actinic keratoses, throughout her legs and thighs bilaterally. She presented to a central Florida dermatology clinic with complaints of persistent bumps on her right lower leg despite therapy with diclofenac sodium gel 3% and 5-fluorouracil cream 5%. Biopsies of skin specimens from the right lower leg revealed a dermal abscess that contained spherical funguslike organisms, with periodic acid-Schiff staining revealing 6- to 10-mu m organisms with internal septations, which are characteristic of P wickerhamii.