Filamentous Histoplasma capsulatum endocarditis involving mitral and aortic valve porcine bioprostheses.

We report a case of histoplasmosis capsulati endocarditis simultaneously infecting a mitral and aortic porcine bioprostheses. Histologically, the fungus demonstrated a diversity of morphologies, ranging from typical, intracellular, 2- to 5-micron yeast cells, to septate and branching hyphae, to bizarre hyphae with vesicular swellings. Cultures obtained from both valves were positive in four days. The combination of unexpected histologic appearance and rapid growth in culture may pose problems in diagnosis.