Primary left ventricular intimal sarcoma: a case report of multimodality imaging and molecular confirmation

Primary cardiac intimal sarcoma is a rare malignant mesenchymal neoplasm whose intracavitary appearance may mimic other cardiac masses. We report a woman in her early 60s with recurrent palpitations and occasional exertional dyspnea. Transthoracic echocardiography (TTE) demonstrated a giant, highly mobile, irregular multilobulated mass occupying most of the left ventricular cavity, with slit-like interlobular clefts and a probable broad-based attachment near the apical interventricular septum. Low-velocity color Doppler demonstrated residual flow around and between lobules, while continuous-wave Doppler showed a peak left ventricular outflow tract velocity of 3.09 m/s and a peak instantaneous gradient of 38 mmHg. Cardiac computed tomography angiography (CTA) showed a large relatively hypoattenuating left ventricular mass with heterogeneous enhancement: some portions showed no obvious enhancement, whereas others showed mild enhancement; the interface with the ventricular wall was locally indistinct, so myocardial involvement could not be excluded. After induction of general anesthesia, intraoperative transesophageal echocardiography (TEE) showed the mass nearly filling the left ventricular cavity, but the attachment and fine multilobulated architecture were less clearly seen than on preoperative TTE. The patient underwent tumor resection with concomitant mitral valve repair. Histology showed mildly atypical spindle cells with fascicular and focal perivascular growth, readily identified mitotic figures, and mild myxoid stromal change. Immunohistochemistry showed MDM2 positivity, and fluorescence in situ hybridization demonstrated MDM2 and CDK4 amplification, supporting the diagnosis of intimal sarcoma. At approximately 2 weeks after surgery, follow-up TTE showed no residual or recurrent left ventricular mass, preserved left ventricular systolic function, minimal residual mitral regurgitation, and a peak outflow tract velocity of 0.92 m/s without residual obstruction. Postoperative 18F-FDG PET/CT performed at approximately the same time identified no definite extracardiac primary tumor or obvious distant metastatic lesions. The case illustrates how multimodality imaging can define the anatomy and hemodynamic effects of a rare left ventricular intimal sarcoma, while histopathologic and molecular findings remain essential for definitive diagnosis.