Severe functional mitral stenosis due to a left atrial myxoma masquerading as asthma.

While cardiac myxomas are the most common primary cardiac tumours, their overall incidence remains rare. Most cases (90%) are sporadic and occur in the third-sixth decades of life with a female predominance and have a specific predilection for the left atrium (75%). While often asymptomatic, clinical presentations depend on the tumour size, architecture and location. Echocardiography remains the mainstay for diagnostic evaluation. Tumour resection is the only definitive treatment. Histopathology using H&E and immunohistochemical stains, such as calretinin and CD34, confirms the diagnosis. We present a case of a patient with reported history of asthma who presented with recurrent acute on chronic shortness of breath refractory to inhaler therapy, multiple outpatient visits and hospitalisations for 'asthma exacerbations'. After further evaluation, she was diagnosed with a left atrial myxoma attached to the inferior aspect of the intra-atrial septum complicated by severe functional mitral stenosis. © BMJ Publishing Group Limited 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.