Tamoxifen-induced venous thromboembolism in a young male

A 25-year-old man was being treated with tamoxifen for oligozoospermia. He was admitted with progressive shortness of breath, hemoptysis, and left-sided pleuritic chest pain for 5 days. Pulmonary embolism was suspected based on presenting symptoms, electrocardiogram, chest x-ray examination, ventilation-perfusion (V/Q) scan, and confirmed by computed tomography (CT) pulmonary angiography. CT pulmonary angiography showed a large pulmonary embolism, but additional investigations failed to reveal a primary source of embolism eg, deep vein thrombosis or right-. sided cardiac thrombus. The patient was treated with IV heparin. The clot resolved completely, demonstrated by follow up CT angiography, and he was discharged on oral anticoagulation. Antithrombin III level was significantly reduced (31% activity). The cause of venous thromboembolism may have been thrombophilia induced by tamoxifen.