P324 A CASE OF ATRIAL MYXOMA WITH UNUSUAL CLINICAL PRESENTATION

Abstract

Myxoma (mx) is the most frequent adult cardiac tumour, that often poses a difficult diagnostic challenge due to the variety and aspecifity of presenting clinical signs. Alongside the more typical clinical onset caused by intracardiac obstruction and systemic embolization, mainly at cerebral level, a mx may initially manifest itself with nonspecific systemic symptoms such as fever, weight loss, fatigue, skin rash, myalgia and arthralgia. We present the case of a 58–year–old woman diagnosed in December 2018 with idiopathic, serum–negative arthritis of the metacarpophalangeal joint of the first finger of the right hand, treated with methotrexate (Reumaflex 10 mg/week s.c.), hydroxychloroquine sulphate (Paquenil 200 mg/day per os) and corticosteroids cycles; in January 2021, this therapy was suspended by the patient (pt) as ineffective. In April 2021, pt was admitted for bilateral SARS–CoV–2 pneumonia. As dyspnoea and fatigue persisted during moderate physical activity (NYHA class II), the pt underwent a cardiological examination on 13 August, when echocardiographic diagnosis of a left atrial mass with the appearance of a mx was made. Interleukin–6 (IL–6) was assayed for a suspected relationship between the cardiac tumour and rheumatic symptoms and was found to be elevated (490 pg/m)l. On 23 August, cardiac surgery was performed to remove the left atrial mass by right minithoracotomy. Histopathological examination confirmed that the 3.5 x 2.5 x 1.5 cm neoformation was a mx. On 1 September, strong attenuation of joint pain and IL–6 reduction to 107 pg/ml was detected. On 9 October, resolution of rheumatic symptoms and normalisation of IL–6 to 3.7 pg/ml (N.V < 7) occurred. This clinical case is emblematic of the long time that sometimes can elapse between the first clinical manifestation and the diagnosis of mx. Also the widespread use of echocardiography did not significantly reduce the diagnostic delay when cardiac symptoms are absent. In a large number of cases, onset symptoms mimicking autoimmune connective tissue disease are reported for 5% (“Clinical presentation of left atrial cardiac myxoma. A series of 112 consecutive cases” Medicine (Baltimore) 2001 May;80(3):159–729). The monoarticular localisation we describe is however unusual. Finally, our observation confirms that the association between mx and systemic symptoms is most likely due to IL–6 synthesis by tumour cells.