Obstructive Shock Due To Metastatic Chondroid Osteosarcoma Adherent To The Tricuspid Valve

Abstract

Introduction Intracardiac metastatic malignancy is rarely recognized as a potential cause of obstructive shock. Further, when present, such metastases may be mistaken for other causes such as pulmonary embolism. We describe a case of obstructive shock arising from a tricuspid valve metastasis of a chondroid osteosarcoma. Case Presentation A 55-year-old Caucasian woman presented to another facility with exertional syncope. Her history included chondroid osteosarcoma of the right iliac wing requiring hemipelvectomy 5 years previously. Her only recent symptoms were chronic right lower extremity lymphedema and 1 month of bruising. Recent history included prolonged travel 1 day previously, and medications included transdermal estrogen. On presentation, she had hypotension responsive to fluids, with labs remarkable for isolated thrombocytopenia. Electrocardiography was consistent with right heart strain, and a precordial systolic murmur was noted. Computerized tomography (CT) reportedly showed a pulmonary embolism (Fig.1). The patient was transferred to our center for management. Following transfer, transthoracic echocardiography showed right ventricular thrombus versus mass, with extension into the inferior vena cava (IVC) and pulmonary artery, as well as signs of pulmonary hypertension and right ventricular (RV) dysfunction. Despite therapies including platelet transfusion, therapeutic anticoagulation, IVC filter placement, and tPA infusion via catheters placed into the emboli via arteriography, the patient experienced sudden-onset hypotension with clammy extremities, followed by pulseless electrical activity arrest. She expired despite resuscitation including crystalloid, vasopressors, and systemic tPA. At autopsy, a rubbery mass (Fig.2) was found, adherent to the tricuspid valve and chordae tendineae. The mass extended through the pulmonary valve into the pulmonary arteries. No thrombi were noted in the pulmonary vasculature or elsewhere. Histology of the mass demonstrated atypical cartilage consistent with the patient's original tumor. Discussion While rare, cardiac metastases of osteosarcoma have been described, mainly since adjuvant chemotherapy was introduced. Common patient characteristics include female sex, older age at diagnosis, and longer interval to metastases. Presenting signs and symptoms are generally nonspecific and related to pulmonary hypertension, although isolated thrombocytopenia has been noted. Echo and CT are commonly used but may not differentiate tumor from thrombus without serial images during anticoagulation, making initial cardiac magnetic resonance imaging preferable. Complete surgical resection is the therapy of choice and substantially improves survival. Critical care therapies should optimize RV preload and reduce left ventricular afterload. However, the most important action is including intracardiac malignancy in the differential diagnosis of patients with a history of malignancy who present with RV dysfunction. (Figure presented) .