P844 A stroke of bad fortune

Abstract

Abstract Case description We report the case of a 78 year old man who was referred to our hospital following identification of an intracardiac mass on transthoracic echocardiogram (TTE). The study was for work-up of a recent left middle cerebral artery thromboembolic stroke, with successful endovascular clot retrieval. His only other active medical issue was metastatic prostate cancer with bony involvement, on palliative hormone therapy with a well controlled prostate specific antigen level. He was an ex-smoker and and had an ECOG performance status of zero. On physical examination, the patient was clinically well, with unremarkable cardiopulmonary auscultation. The TTE demonstrated an echodense mass in the left atrium (LA), with Doppler colour giving a suggestion of its size (image A). The subsequent transoesophageal echocardiogram illustrated a large, well defined, heterogenous, echodense mass dominating the LA (image B). It was not adherent to the interatrial septum. There was no significant spontaneous echocontrast or thrombus formation in the left atrial appendage (LAA). Considering the location of the mass, the presumptive diagnosis of atrial myxoma was less likely. Differential diagnoses we considered included pure thrombus, infection and benign or malignant cardiac tumours. It was unlikely that this patient had a pure thrombus only considering the LAA was clear. He also did not have any non-specific or focal clinical features suggestive of infection. The patient went on to have a gated CT thoracic aortogram, which showed a contrast-enhancing soft tissue mass within the LA measuring approximately 50x40 millimetre, which invaded into the left inferior pulmonary vein, and was contiguous with a soft tissue mass in the left lower lobe of the lung (image C). He also had a positon emission tomography scan, which showed the highly metabolically active mass in the lung invading into the left inferior pulmonary vein, and as well as left atrium (image D). The patient underwent a biopsy of this left lower lung lesion, which confirmed squamous cell carcinoma of lung origin. Due to the large tumour burden in the LA, the joint decision with medical and radiation oncology teams, was not to administer systemic chemo- or localised radiotherapy, as this would lead to high risk of tumour embolisation. The patient also had a short period of therapeutic anticoagulation with intravenous unfractionated heparin to treat the likely thrombotic coating to the left atrial tumour extension, but developed a retroperitoneal haematoma, and hence anticoagulation was ceased. The patient was referred to palliative care services, and returned back to the community. Conclusion Cardiac tumours, whether primary or secondary, are rare. They are most frequently identified on post-mortem examination. This case is unusual, in that the patient had a second primary tumour and has remained completely asymptomatic prior to embolic presentation, despite the large size of the mass. Abstract P844 Figure 1.