Severe mitral stenosis secondary to eosinophilic granulomatosis resolving after pharmacological treatment

We present a case of 44-year-old woman who underwent effective pharmacological treatment of severe mitral stenosis. The patient was hospitalized due to rapidly progressive dyspnea. Her medical history included asthma, perennial rhinitis, and nasal polyps. Echocardiography showed a mass of the left ventricle involving the mitral valve; cardiac MRI suggested acute endocarditis. Severe peripheral blood eosinophilia was found. Eosinophilic granulomatosis with polyangiitis was diagnosed; treatment with prednisone and cyclophosphamide was started. Despite the clinical improvement, severe mitral stenosis persisted, surgical treatment was planned. However, evaluation after 6 cycles of cyclophosphamide pulse therapy revealed a significant regression of the valvular disease.