Right atrial myxomas and hairy cell leukaemia: coincidence or causal relationship?

A 69-year-old man presented with a 6-week history of progressive breathlessness, fatigue and epistaxis. There was no significant past medical history apart from atrial fibrillation diagnosed 2 years earlier when echocardiography was normal. On examination, he was anaemic and had a new mid-systolic murmur. A full blood count revealed pancytopenia (haemoglobin=10.9 g/dl; white cell count=1.7×10 9 /litre; platelets=52×10 9 /litre) and bone marrow histology confirmed a diagnosis of hairy cell leukaemia (Figure 1). A ‘staging’ computed tomography scan of the thorax and abdomen showed no lymphadenopathy but splenomegaly and a mass in the right atrium. Transthoracic echocardiography confirmed the presence of a large right atrial mass, attached to the atrial free wall and a small pedunculated mass attached low on the interatrial septum (Figure 2). Both right and left ventricular contractility were impaired and there was mild tricuspid regurgitation. He was treated with intravenous cladribine (2-chlorodeoxyadenosine) to a total dose of 0.9 mg/kg. His blood count recovered to normal levels over the next 3 months and the splenomegaly resolved. There was, however, no change in the size of the right atrial mass which was then removed surgically. At open heart surgery, both the small pedunculated tumour and the larger, ovoid, more sessile, gelatinous right atrial mass (60 mm diameter) were excised (Figures 3 and 4). Histology showed fusiform cells in a myxoid stroma typical of myxoma (Figure 5), with the larger mass possessing laminated thrombus and degenerative changes.