Esporotricosis. Valor diagnóstico del cuerpo asteroide

Abstract

A 52 year old patient was seen because of nodular, verrucous, fissured, cord-like and cicatricial lesions on the left leg, from the foot to the knee. The lesions had started two years earlier with an abrasion caused by the trunk of a tree. The clinical picture suggested sporotrichosis or chromomycosis. A black mold was cultured, and on direct examination, pigmented spores were seen. With these findings, the diagnosis of chromomycosis was apparently confirmed. However, the biopsy did not show the brown yeasts usually found within microabscesses in the granulomatous inflamation of the dermis in cases of chromomycosis. On the other hand, it did show asteroid bodies characteristic of sporotrichosis. For this reason, new cultures and two additional biopsies were obtained. This time two different colonies were identified: one of the same black mold and the other of Sporothrix schenkii. We again found asteroid bodies in the serial sections of the biopsies. In contrast, we were never able to find the pigmented yeast with the characteristic septa so easily demonstrable in the granulomatous microabscesses seen in the dermis in chromomycosis. There were occasional brown spores and short pigmented hyphae only in the crusts. The patient recovered completly after 4 months of treatment with potassium iodide. We interpreted the black mold to be a contaminant, present only in the crusts. So, chromomycosis should be diagnosed by culture of the fungus and biopsies from the lesions. Eventually, other cases of this superficial contaminant mold limited to crusts, without major clinical or histological signs, but very prominent in culture, may be found. The asteroid body of sporotrichosis is specific and characteristic. When it is found, the fungus can usually be recovered in culture. If for any reason it is not possible to isolate the organism, the presence of sporotricotic asteroid bodies is sufficient evidence to give the patient treatment with potassium iodide.