Human protothecosis: A case report in northeastern Brazil

Abstract

We describe a case of extensive human cutaneous protothecosis in the northeastern of Brazil. The diagnosis was made through histopathological examination of skin samples and culturing on Sabouraud dextrose agar, with identification through mass spectrometry. Treatment with itraconazole failed and was switched to liposomal amphotericin followed by voriconazole with clinical cure. Prothotecosis should be a diagnostic hypothesis when there are skin lesions after trauma, specially in situations of atypical evolution.

Keywords: Protothecosis; Skin diseases; Soft tissues infectious.

Fig. 1

A – Hyperemic infiltrative lesion with burning pain, presented at the first consultation (D0). B – Lesion with worsening of its characteristics, presenting micro-ulcerations, worsening of pain and mild secretions, with secondary infection, under treatment with itraconazole (400 mg/day) (D+30). C – Upper limb, 18 months after the end of treatment with voriconazole (200 mg, every 12 hours for 6 months) (D+615).

Fig. 2

A - Prototheca colony seeded on Sabouraud dextrose agar medium. B - Direct investigation under light microscopy, using KOH and permanent black Parker ink. C - Protothecosis. HE 20x. Skin section showing large thick-walled Prototheca, containing spores, intensely silvered. Note multiple Langerhans giant cells. Elsewhere, the epidermis is involved, showing hyperplasia. D - Tissue section, 40x, showing ovoid or spherical Prototheca with conspicuous walls that became intensely stained using the usual stains for fungi, i.e., Gömöri's methenamine and periodic acid-Schiff (PAS).