A 70 year old woman was admitted because of breathlessness and chest discomfort. An ovarian tumour had been resected six months before admission, and was diagnosed as a mature cystic teratoma with squamous cell carcinoma. On physical examination, hypotension, peripheral oedema, and jugular vein dilatation were evident. Transthoracic echocardiography revealed a high echoic large mass in the right ventricular (RV) cavity, an enlarged right atrium (RA), and pericardial effusion (top left, parasternal short-axis view; top right, apical four chamber view; LV, left ventricle). No masses were detected elsewhere. Contrast computed tomographic scans showed a large filling defect in the RV cavity. The patient died of developmental cardiogenic shock two weeks later.

Necropsy revealed that a cardiac tumour arising from the RV free wall occupied the RV cavity almost completely (bottom left). Pathological diagnosis of the tumour was squamous cell carcinoma, suggesting metastasis of the ovarian cancer previously resected (bottom right). Surprisingly, metastatic lesions were not found in the other major organs, including brain, lung, liver, kidney, as well as adrenal gland. The pericardium is the most common site of cardiac metastasis of malignant tumours and the resultant cardiac tamponade is the most frequent cause of hemodynamic compromise. However, the involvement in endocardium is extremely rare. In contrast, only a few cases with intracavitary metastatic lesions causing haemodynamic compromise have been reported. In the present case, the sole metastatic tumor grew progressively without any other metastatic lesions in the whole body.