1356771 - Lightning Strikes Twice: Recurrent Sarcoma and Utilization of Multimodality Imaging

50 year old male with a past medical history of atrial sarcoma status post resection and chemotherapy (with active surveillance with CT/MRI and no evidence of recurrence for 4 years), hypertrophic cardiomyopathy, hypertension and diabetes who presented to the emergency department with left hand numbness and abnormal speech. CT and MRI head showed acute right middle cerebral artery ischemia in the right temporal lobe. Transthoracic echocardiogram was performed and revealed a large, highly mobile mass attached to the anterior leaflet of the mitral valve concerning for myxoma vs. vegetation (Figure 1). Cardiac magnetic resonance (CMR) was obtained for further tissue characterization and findings revealed an irregular shaped mass on the mitral valve consistent with recurrence of sarcoma (Figure 2). PET/CT further demonstrated increased activity in the mitral valve and mitral annulus. Hospital course was complicated with findings of a non-occlusive superior mesenteric artery thrombus concerning for tumor emboli (Figure 3). Patient underwent thrombectomy and pathology demonstrated metastatic undifferentiated spindle cell sarcoma. Due to embolism and extent of disease on CMR, patient underwent surgical tumor resection with aortic and mitral valve replacement and resultant pathology was consistent with undifferentiated sarcoma.

Diagnostic Techniques and Their Most Important Findings:

The cardiac masses were identified on the anterior and posterior leaflet of the mitral valve and aortomitral curtain (Figure 2A, 2B and 2C) and were further characterized on CMR. The mass on the mitral valve was isointense on T1 spin-echo image (Figure 2D), and hyperintense on T2 spin-echo image (Figure 2E). The mass had heterogeneous late gadolinium enhancement at the core of the mass (Figure 2F). The smaller mass on the annulus of the mitral valve also shared the same characteristics. Perfusion imaging demonstrated enhancement of both masses, suggesting vascularity.

Learning Points from this Case:

Undifferentiated sarcoma is a very rare and aggressive type of primary cardiac tumors that carries a poor prognosis. Utilization of multimodality imaging is key to the diagnosis of cardiac tumors. We demonstrate a case where the patient had been without recurrence for four years, and the key differential after initial work up, based on echocardiogram, for our patient's stroke was vegetation, thrombus or myxoma. However, with CMR, we were able to perform tissue characterization of the mass and show the extent of cardiac involvement, which aided in the course of efficient medical and surgical management.