A Rare Central Thoracic Tumor

Journal of Thoracic Oncology ® • Volume 9, Number 6, June 2014 CASE HISTORY A 51-year-old male former smoker, without relevant medical history, had progressive dyspnea on exertion, cough, minor hemoptysis, and a large suprahilar tumor-like mass on chest radiography. A positron emission tomography–computed tomography scan at the referring center showed a lobulated mass invading the mediastinum and right pulmonary artery, and filling defects suspect for pulmonary emboli (Fig. 1). The lesion had moderate F-fluorodeoxyglucose uptake. At bronchoscopy, the right upper lobe was suboccluded by a smooth mass. Forceps biopsies revealed necrosis of unclear origin. The patient was referred for workup. The absence of venous thrombosis, intracardiac clots, pulmonary hypertension, and arterial hypoxemia reduced the likelihood of widespread pulmonary emboli. After reassessment at our thoracic oncology multidisciplinary meeting, a surgical procedure was proposed based on the suspicion of a tumor mass originating from the pulmonary artery. A right-sided intrapericardial pneumonectomy and left-sided pulmonary endarterectomy (PEA) through sternotomy was performed on extracorporal cardiopulmonary bypass. The procedure and postoperative recovery were uncomplicated. The pneumonectomy specimen showed a tumor completely obliterating the right pulmonary artery and protruding into the right upper lobe bronchi. Left PEA from pulmonary valve level to the subsegmental branches was able to remove a pale smooth mass (Fig. 2). Pathology showed a tumor in the pulmonary artery wall with a heterogeneous aspect. Essentially, it concerns a spindle cell process with cellular fascicular to myxoid areas. The tumor cell nuclei were atypical with a mitotic count of 5 of 10 hpf. Immunohistochemistry revealed (nuclear) MDM2 expression and diffuse epidermal growth factor receptor expression (Fig. 3). Stains for desmin, α-smooth muscle actin, CD31, and CD34 were negative. FISH analysis showed strong amplification of the MDM2 and PDGFRA genes, thus confirming an intima sarcoma.