A 50-year-old male patient was admitted for shortness of breath (New York Heart Association functional class II) and constitutional syndrome of 1 month’s duration. Physical examination was remarkable for a grade 3/6 systolic murmur best heard at the second left intercostal space. Blood pressure was 103/88 mmHg, heart rate was 84 beats/minute and his oxygen saturation at rest was 93%. Electrocardiogram and blood gases at rest were normal. Laboratory tests revealed microcytic hypochromic anaemia, and colonoscopy disclosed a colon adenocarcinoma. Echocardiography was subsequently performed, revealing a mildly dilated right ventricle, mild tricuspid regurgitation, no pulmonary regurgitation and severe elevation of right ventricular systolic pressure (70 mmHg), as well as a 50 × 33 mm mass in the main pulmonary trunk extending into both pulmonary artery branches and producing severe stenosis with minimal residual lumen ( Fig. 1 ). Although computed tomography showed that the mass did not enhance with contrast ( Fig. 2 ), suggesting a giant thrombus as the most likely diagnosis, pathological analysis of the mass confirmed a pulmonary leiomyosarcoma. The patient underwent successful surgical resection of both tumours and remains alive 18 months after the initial diagnosis.
