Nonbacterial thrombotic (marantic) endocarditis in a patient with colorectal cancer

Marantic endocarditis, presently termed nonbacterial thrombotic endocarditis (NBTE), is an infrequent post-mortem diagnosis in the adult population but a not so rare event in the course of neoplastic conditions.

We describe the case of a 74-year-old woman with advanced sigmoid adenocarcinoma, who developed aseptic vegetations in the right atrium of the heart. Systemic anticoagulation therapy was started, and upon clinical improvement systemic chemotherapy was added, resulting in partial response to antineoplastic therapy along with improvement of her cardiopulmonary status. A new cardiac assessment upon tumor recurrence was unable to distinguish the previously described lesions but disclosed a small mitral valve vegetation, in the absence of any signs or symptoms. The patient was again treated with chemotherapy and remains asymptomatic with stable disease.

Although a hypercoagulable state may be etiologically related to malignant conditions, a strong clinical suspicion of NBTE is required. In these cases, it is often difficult to establish a definite diagnosis; however, immediate anticoagulation treatment is mandatory for the prevention of de novo or further thromboembolic events.