Bicalutamide-induced Eosinophilic Pneumonitis - A Serendipitous Diagnosis

Bicalutamide is a first-generation non-steroidal anti-androgen. Interstitial lung disease is a rare side effect of bicalutamide. Centres in the United States of America and Japan have previously reported bicalutamide-induced interstitial lung disease. This has not been reported in the United Kingdom. An 86-year-old Caucasian man with a history of advanced prostate cancer, on oral bicalutamide, presented to the emergency department with sudden onset dyspnoea and chest tightness. Bicalutamide-induced eosinophilic pneumonitis co-existing with community acquired pneumonia, and left ventricular systolic dysfunction were suspected, based on physical examination findings and investigation results that include blood tests, chest radiographs, echocardiogram, in addition to computed tomography pulmonary angiogram performed to rule out pulmonary embolism. There was a marked clinical, biochemical and radiological improvements after discontinuation of bicalutamide, initiation of a high-dose steroid, intravenous antibiotics, and diuretic. Prostate cancer retains a high incidence in the Western population. Recognising toxicities due to anti-androgen therapies is relevant to clinical practice.