RESUMEN
INTRODUCTION: Androgen deprivation therapy remains the essential treatment for disseminated prostate cancer. Interstitial pneumonitis following this therapy has been documented for just a few cases. However, reported cases frequently describe the onset of symptoms after recent administration (days or a few weeks) of both GnRH analogues and androgen antagonists, which makes the precise individual impact of each treatment difficult to estimate. CASE REPORT: This report presents a case of a 94-year-old patient with interstitial pneumonitis whose onset started three months after the first dose of leuprorelin and bicalutamide for a metastatic prostate cancer. MANAGEMENT AND OUTCOME: Once other possible diagnosis were ruled out, empiric corticosteroid treatment was initiated within 48 h of the admission. A spectacular clinical and radiological improvement was observed after 3 doses of steroids, enabling the patient to recover his basal respiratory situation. We considered that the most probable cause was toxic interstitial pneumonitis induced by leuprorelin. DISCUSSION: To our knowledge, it describes the longest interval between last administration of antiandrogen therapy and the development of pneumonitis. This fact may support a direct relation with leuprorelin, whose serum levels remain high for months because of its long-acting depot formulation.