A 58-year-old man presented to the cardiology clinic with intermittent chest pain and a 5-day history of palpitations that were not associated with exercise. His medical history revealed that a cardiac mass was detected at echocardiography performed 3 years ago and for similar symptoms. However, he was lost to follow-up before his examinations were concluded. Apart from that, his medical history was unremarkable, and he had not experienced any cardiac symptoms in the intervening 3 years. He had a family history of sudden cardiac death, and his father died of a heart attack when he was 57 years old. Physical examination findings were unremarkable except for increased blood pressure (150/105 mmHg). Laboratory findings, including a complete blood count and creatinine, C-reactive protein, electrolyte, serum calcium, and troponin T levels, were within normal limits. Electrocardiography (ECG) was performed and revealed sinus rhythm and ST depression in the left precordial leads. T ransthoracic two-dimensional echocardiography revealed an irregular left ventricle mass. The patient subsequently underwent contrast-enhanced ECG-gated cardiac CT followed by cardiac MRI to evaluate the left ventricle mass (Figs 1–5).Scanogram of the chest showed a calcified lesion superposed to the heart (Fig 1). ECG-gated cardiac four-chamber (Fig 2A), left ventricle outflow tract (Fig 2B), two-chamber (Fig 2C), and short-axis (Fig 2D) CT images revealed a calcified irregular mass with a tubular and infiltrative appearance in the basal inferior segment of the left ventricle, with extension into the mid-inferior wall, mid-inferior septum, and inferior papillary muscle. Three-dimensional volume-rendering reconstructions of a cardiac CT image showed the hyperattenuating irregular left ventricle mass with fluffy ossification (Fig 3). Axial unenhanced T1weighted double inversion-recovery MRI without fat saturation revealed the irregular hypointense left ventricular mass compared with the myocardium (Fig 4A). Short-axis plane triple inversion-recovery MRI at the midbasal level of the left ventricle showed the hypointense irregular mass infiltrating the mid-inferior wall, mid-inferior septum, and inferior papillary muscle, with no myocardial edema (Fig 4B). Balanced steady-state free precession (b-SSFP) MRI with three-chamber (Fig 4C) and two-chamber (Fig 4D) views of the left side of the heart and axial b-SSFP MRI (Fig 4E) showed the mass was hypointense compared with the myocardium. Midbasal short-axis plane cardiac MRI with cine early first-pass perfusion 30 seconds after contrast medium injection (gadoterate meglumine [0.2 mL per kilogram of body weight], Opaxol; Opakim) showed no contrast enhancement of the left ventricular mass (Fig 5A). Late gadolinium-enhanced phase-sensitive inversionrecovery MRI was performed 15 minutes after contrast medium injection and showed no late enhancement in the left ventricular mass (Fig 5B). The patient underwent transfemoral left ventricle endomyocardial biopsy in an external center, and histopathology revealed no evidence of malignancy or amyloid, but dense fibrous fragments were detected. The patient was diagnosed with cardiac calcified amorphous tumor (CCAT) based on the radiologic and histopathologic findings. Because of the infiltrative nature and extent of the calcified cardiac mass, surgical excision was avoided, and the patient was observed clinically and with imaging methods (echocardiography and MRI). The 6-year follow-up was uneventful, and the lesion was stable. What is your diagnosis?