Revista do Instituto de Medicina Tropical de São Paulo
Print version ISSN 0036-4665
LACAZ, Carlos da Silva et al. Atypical disseminated cutaneous histoplasmosis in an immunocompetent child, caused by an "aberrant" variant of Histoplasma capsulatum var. capsulatum. Rev. Inst. Med. trop. S. Paulo [online]. 1999, vol.41, n.3, pp. 195-202. ISSN 0036-4665. http://dx.doi.org/10.1590/S0036-46651999000300012.
A case of atypical disseminated cutaneous histoplasmosis in a five-year old, otherwise healthy child, native and resident in São Paulo metropolitan area is reported. Cutaneous lesions were clinically atypical. Histologic examination disclosed a granulomatous reaction but no fungal structures could be demonstrated by specific staining nor by immunohistochemical reaction. The fungus was isolated from biopsy material on two different occasions, confirming diagnosis of an unusual fungal infection. The fungus, originally thought to be a Sepedonium sp. due to the large sized, hyaline or brownish colored tuberculated macroconidia and to lack of dimorphism (yeast form at 37 °C) produce H and M antigens, visualized by the immunodiffusion with rabbit anti-Histoplasma capsulatum hyperimmune serum. Patients serum sample was non reactive with H. capsulatum antigen by immunodiffusion, counterimmunoelectrophoresis and complement fixation tests, and immunoenzymatic assay failed to detect the specific circulating antigen. This serum was tested negative by double immunodiffusion when antigen obtained from one of the isolated samples was used. Both cultures were sent to Dr. Leo Kaufman, Ph.D. (Mycoses Immunodiagnostic Laboratory, CDC-Atlanta/USA), who identified them as H. capsulatum by the exoantigen and gen-probe tests. Both clinic and mycologic characteristics of the present case were atypical, suggesting the fungus isolated is an aberrant variant of H. capsulatum var. capsulatum, as described by SUTTON et al. in 199719. Treatment with itraconazole 100 mg/day led to cure within 90 days
Keywords : Histoplasma capsulatum; Cutaneous histoplasmosis; Aberrant strain.