Cutaneous protothecosis - Case report
A 61-year-old white woman, housewife by occupation, born in the state of Rio de Janeiro\nand raised in Araruama, a coastal city in an oceanic lakes region, reported the\nappearance of an erythematous and painful lesion in the right leg. It had developed 15\ndays before on an excoriation caused by local trauma that occurred during\nhospitalization for investigation of muscle weakness in the arms and legs. She was\ntreated with cephalexin 500mg, four times a day, for a week, without improvement of the\nlesion and was referred to the dermatology service. Her medical history disclosed\nhypertension and allergic rhinitis in prolonged treatment with systemic corticosteroids\nin anti-inflammatory doses, since the age of 14-year-old (in the last year,\nintramuscular injections of betamethasone 7mg/week). During hospitalization, a motor and\nsensory neuropathy and type II diabetes mellitus were diagnosed and the treatment with\nmetformin 850mg, 3 times a day, was started, with control of glucose blood level. The\npatient was discharged and the investigation of skin lesions continued in the\ndermatology service.\nDermatological examination revealed an erythematous, tender and painful plaque covered\nby pustules and scabs on the right leg ().\nThe clinical picture suggested the diagnosis of erysipela, staphylococcal folliculitis,\ndermatophytosis and sporotrichosis.\nHematologic and biochemical laboratory findings were normal, except for high glucose\nlevels (150mg/dL) before the introduction of metformin. HIV and hepatitis tests were\nnegative.\nA swab was collected from the pustules in addition to biopsy of the lesion. Cultures\nfrom the swab were performed for bacteria and fungi and were negative or both. Fifteen\ndays after sowing, the cultures on Sabouraud dextrose agar and blood agar, developed\nwhite, creamy, yeast-like colonies ().\nCulture microscopy showed sporangiospores within the sporangia, with morula-like aspect,\nconsistent with Prototheca sp.\nHistopathology revealed a suppurative and granulomatous inflammation in the dermis. The\nperiodic acid-Schiff stain (PAS) revealed morula-like structures in the suppurative area\n(). The same structures were colored in\nblack by the Grocott silver stain ().\nFor species identification, a suspension of the culture was submitted to the\ncarbohydrate assimilation test by the Vitek automated system, indicating P.\nwickerhamii as the causative species.\nAfter the diagnosis of cutaneous protothecosis, treatment was started with itraconazole\nat a dose of 200 mg daily for 3 months with complete healing of the lesion.