B80-5-06 Reversible Hypoxemia Due to Intra-Sarcoma Shunt: A Case Study

Abstract Introduction Solid tumors modify local angiogenesis and co-opt surrounding vasculature to maintain energy supply required for ongoing growth. This process is often complicated by metastasis and hemorrhage. Pulmonary tumors can rarely create intrapulmonary shunt physiology and hypoxemia in this manner; this has been described most often in bronchoalveolar carcinoma. We present a case of malignant intrapulmonary shunt occurring with spindle cell sarcoma, which resolved with arterial embolization. Case Presentation A 72-year-old male with a history of stage IV spindle cell sarcoma with abdominal, vertebral, and pulmonary metastases presented to an outpatient appointment with three weeks of fatigue and decreased exercise tolerance. He had no history of parenchymal lung disease nor any home oxygen requirement. In clinic, he was found to require 6L per minute of supplemental oxygen to maintain saturation of 88%. He was directly admitted to the oncology service. Initial laboratory evaluation was unremarkable. CT imaging demonstrated normal lung parenchyma, no pulmonary embolism, and an 11cm vascular tumor involving proximal branches of the local pulmonary artery (Figure). Transthoracic echocardiography (TTE) with agitated saline revealed a large intrapulmonary shunt. As the patient had limited response to oxygen therapy, this intra-tumoral shunt was deemed the most likely cause of his hypoxemia. Surgical resection was considered but was deemed to confer limited clinical benefit in the setting of multiple metastases. Embolization of the local pulmonary artery was therefore pursued with Interventional Radiology. The patient tolerated the procedure well with complete resolution of hypoxemia post-procedure. His energy and mobility improved, and he was discharged home. Three months later, he continued to require no supplemental oxygen. Discussion While shunt physiology is commonly part of the differential for hypoxemia, it is rarely described as an oncologic complication. This appears to be the first report of such pathology in a sarcoma patient, and the first to report shunt resolution through arterial embolization rather than surgical resection or systemic anti-tumor therapy. In addition, previous cases typically describe shunt detection via selective pulmonary arterial occlusion by Swan-Ganz catheter, whereas here the noninvasive TTE with agitated saline was sufficient. While the few existing reports highlight good response to lobectomy or pneumonectomy, this case highlights the potential for minimally invasive vascular intervention. Despite the metastatic nature of this patient’s disease, he received significant, rapid physiologic and functional benefit from a procedure with less morbidity. Maintaining suspicion of intra-tumoral shunt physiology is appropriate for patients with vascular pulmonary masses and hypoxemia. This abstract is funded by: None