Atrial myxoma as a mimicker of intracardiac thrombus in Behçet's syndrome: a case study with histopathological confirmation.

Cardiomyopathies cause most intracardiac thrombosis (ICT), and Behçet's syndrome (BS) is a rare inflammatory disease that can be responsible for a proportion of ICT. Other inflammatory disorders involved in the aetiology of ICT include antiphospholipid syndrome, Henoch-Schonlein purpura, COVID-19, and Loeffler endocarditis. ICT usually occur during the active phase of BS, and they have a close relationship with vascular involvement. Atrial myxomas are benign cardiac tumours arising from the interatrial septum. They can lead to a substantial acute phase response, making them difficult to distinguish from inflammatory diseases. In this case study, we present a 46-year-old female BS patient who presented with constitutional symptoms mimicking BS flare in a routine follow-up visit and was diagnosed with left atrial myxoma after administration of several lines of immunosuppressives. Then, she underwent surgical tumour excision, and a histopathological examination confirmed the diagnosis.In conclusion, atrial myxoma should be kept in mind first of all when suspecting ICT, and advanced imaging methods such as cardiac magnetic resonance imaging (MRI) should be used if necessary.