A 78 year old man was admitted complaining of cough and sputum. Percutaneous needle biopsy identified a right middle lobe mass as squamous cell carcinoma of the lung. Magnetic resonance imaging (MRI) seemed to show that the tumour in the right middle lobe extended continuously into the left atrium via the right pulmonary vein. Transoesophageal echocardiography (TOE) showed that the atrial mass was polyp-like in shape (about 2.5 cm in diameter) with a centralised low echo area, an irregular surface, and a stalk derived from the area of the right pulmonary vein. Colour Doppler showed blood flow from the pulmonary vein into the left atrium around the stalk of the mass. The patient died 10 months after the first symptoms arose. The necropsy findings were compatible with the clinical image data of MRI and TOE. There were no direct attachments between the atrial mass and the left atrial wall other than the stalk.  Few reports of primary lung cancer with intra-left atrial extension via the pulmonary vein have been previously documented. Patients with intracardiac metastases are exposed to the risk of tumour embolisation during operation on the lung or at spontaneous attack. Fortunately, there was no massive tumour embolism in our case. In cases of malignant tumour suggesting cardiac invasion, TOE should be performed to elucidate the mode of invasion of the tumour. This information may not only prove valuable in predicting the prognoses, but may also be essential in deciding the method of treatment and follow-up observations of these patients.

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Figure 1

(A) MRI shows that the main tumour (MT) in the right middle lobe seems to extend directly into the left atrium (LA) through the right pulmonary vein via a stalk-like projection (arrow) and to make an intra-atrial abnormal invasive mass (*). (B) TOE shows the mass (*) in the LA measures about 2.5 cm in diameter. Colour Doppler imaging reveals the mass to have a stalk (S) derived from the right pulmonary vein (arrowhead) which appears to provide its blood flow (PVF). The broken line outlines the edge of the invasive mass

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Figure 2

Necropsy findings. The primary tumour in the lung (main tumour) directly extends into the right middle pulmonary vein (green arrowheads) to form a tumour stalk (S) through the vein as well as the invasive mass (IM) in the left atrium (LA). The primary tumour does not directly invade through the LA wall, which forms a clear border (red arrowheads) between the main tumour and the LA lumen.