Progressive disseminated histoplasmosis in an apparently immunocompetent patient with a bioprosthetic aortic valve

Abstract

Histoplasma capsulatum is an endemic fungus in eastern Canada. This organism has a wide spectrum of manifestations ranging from isolated pulmonary to disseminated disease. The latter usually occurs in immunocompromised hosts or those with substantial environmental exposure. In rare instances, disseminated histoplasmosis can present as an endovascular infection or chronic progressive disseminated histoplasmosis. If not recognized, these entities are almost uniformly fatal. We report a case of an immunocompetent man with a history of longstanding constitutional symptoms. An infectious cause was initially presumed to be unlikely given the chronic nature of his presentation and an extensive series of negative investigations. A diagnosis was only obtained post-mortem upon the unusual detection of both yeast and hyphal forms in blood culture bottles inoculated with a bone marrow aspirate.