Cutaneous protothecosis. A clinicopathologic study.

In what we believe to be the first case of cutaneous protothecosis identified in Taiwan, a 5-year-old Chinese girl presented with a pruritic erythematous plaque on her right upper eyelid. A clinical diagnosis of eczematous dermatitis was made initially, and sporotrichosis was diagnosed subsequently. Later, histopathologic and cultural studies of the lesion finally led to the diagnosis of protothecosis. The recognition of the characteristic sporangia containing symmetrically arranged endospores is the most important initial diagnostic clue of protothecosis. Biochemical assimilation tests and direct immunofluorescence study using species-specific antibodies identified the organism as Prototheca wickerhamii. Systemic ketoconazole treatment proved to be effective for our patient. The in vitro minimal inhibitory concentrations of tetracycline hydrochloride, amphotericin B, and ketoconazole were also determined.