An exotic sinusitis.

We report a case of sinusitis caused by mixed free-living amoebae, Acanthamoeba and Naegleria, in an immunocompetent host; this has not been documented before. Free-living amoebae should be considered in the differential diagnosis of pathogens that cause sinusitis with or without central nervous system involvement, especially when bacteria or fungi are not found by smear, biopsy or culture.