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.Un hombre de 52 años presentó lesiones costrosas, verrucosas, fisuradas, acordonadas y cicatriciales en la rodilla, pierna y pie izquierdos, de 2 años de evolución, luego de trauma contra un Arbol. Clínicamente se pensó en esporotricosis y cromomicosis. El cultivo mostró un moho negro y el examen directo hifas y esporos pigmentados, por lo cual se diagnóstico cromomicosis. La biopsia no mostró levaduras carmelitas en la inflamación granulomatosa con microabscesos de la dermis, sino cuerpos asteroides esporotricósicos por lo cual se hicieron nuevos cultivos y biopsias. Aquellos revelaron el crecimiento del mismo moho negro y de Sporothrix schenkii. En los múltiples cortes seriados de todas las biopsias se vieron cuerpos asteroides esporotricósicos y nunca se demostraron en la dermis levaduras septadas, pigmentadas tan fáciles de ver en la cromomicosis. En algunos focos se observaron esporos marrones e hifas cortas pigmentadas en las costras. El paciente curó con loduro de Potasio. Pensamos que el moho negro es un saprofito presente únicamente en las costras, originando una contaminación superficial sin repercusión clínica y difícilmente demostrable histopatológicamente, pero muy aparente en el cultivo. Este, en la cromomicosis, debe ir acompañado de biopsia que confirme la presencia de levaduras pigmentadas en la dermis. El cuerpo asteroide de la esporotricosis es específico y característico. Cuando se ve, debe insistirse en el cultivo del hongo, pero si ello no es posible, es indicio suficiente para instaurar el tratamiento específico