Corynebacterium endocarditis. Difficult diagnosis in an elderly woman.

Physicians have been reminded repeatedly of the many faces of bacterial endocarditis. In this case, Corynebacterium endocarditis presented as an occult malignancy and eluded diagnosis for six months. The coryneform isolates found in cultures are often considered to be contaminants because of their ubiquitous nature, sometimes causing a delay in diagnosis. Patients with culture-negative endocarditis or Corynebacterium "contamination" should be treated as having Corynebacterium endocarditis pending results of microbiologic isolation tests.