261 Invasive Pulmonary Artery Intimal Sarcoma: A Rare Case of an Aggressive Tumor With Extended Survival.

Introduction: Intimal sarcoma of the pulmonary artery is a rare and aggressive tumor. We present a case of a high-grade primary pulmonary artery intimal sarcoma with extended patient survival status post pneumonectomy. Methods: The patient was a 59-year-old man who presented with worsening dyspnea. Imaging demonstrated a large mass within the right pulmonary artery, with high avidity on PET scan, suspicious for tumor. A right pneumonectomy was performed. The right lung was received with 7 cm of pulmonary artery attached. Obstructing the entire length of artery was a fleshy, white-tan mass with focal attachment to the arterial wall. The specimen was serially sectioned, revealing the mass to consist of heterogeneously soft to fibrous tissue and focally hemorrhagic regions, with significant retrograde extension into the peripheral pulmonary circulation. Histologic examination revealed predominantly spindle-shaped and pleomorphic cells without evidence of specific differentiation, in a background of variably fibrillar, myxoid and fibrous stroma. The tumor arose from the intima of the pulmonary artery, with invasion through the wall and into the adjacent pulmonary vein, as well as into the peripheral parenchyma. Extensive necrosis was noted, as were numerous and occasionally bizarre mitotic figures. An extensive immunohistochemical panel was performed, but was nonspecific. The morphology and growth pattern were most consistent with a primary intimal sarcoma of the pulmonary artery. Conclusions: Intimal sarcoma of the pulmonary artery is a rare and lethal disease, with a one-year mortality rate of 80%. Surgery is the mainstay of treatment, with one case series indicating that evidence of invasive disease renders the patients inoperable and requiring chemoradiotherapy. Our patient is alive and disease free after an interval of approximately 27 months, possibly demonstrating that surgery for invasive disease can offer a survival benefit. [ABSTRACT FROM AUTHOR]