PULMONARY VEIN INVASION: NOT YOUR TYPICAL PULMONARY EMBOLISM

Abstract

SESSION TITLE: Lung Cancer 3 SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: 10/09/2018 01:15 PM - 02:15 PM INTRODUCTION: Lung cancer is one of the leading causes of death, however invasion of a primary pulmonary tumor into the pulmonary vessels is very rare. To date, few cases of tumor invasion involving the pulmonary vessels have been reported. CASE PRESENTATION: We report a 67-year-old male with presentation of cough, wheezing, and shortness of breath with extensive squamous cell lung carcinoma on PDL-1 therapy. He subsequently under went Computed Tomography Angiography (CTA) of the chest which demonstrated a large filling defect in the left atrium suspicious for tumor thrombosis measuring 2.5 cm x 3 cm in diameter extending into the right pulmonary vein. Lower extremity venous doppler was negative to suggest deep vein thrombosis. Initial treatment consisted of intravenous heparin however after detailed review, it was concluded that the filling defect was due to extension of squamous cell carcinoma into the left atrium and proximal pulmonary vein, rather than pulmonary thromboembolism (PE). DISCUSSION: Pulmonary vessel invasion causing thrombosis and occlusion due to primary pulmonary tumor is extremely rare. The most common incidence of vascular thrombosis is seen in angiosarcoma, however can be also seen in extra thoracic malignancies and pulmonary thromboembolism (1). Typically, microscopic vascular invasion by tumor is often seen, but gross invasion into pulmonary vascular structures is a rare entity (3). To date, there is only a handful cases reported in the literature, with various clinical presentations.Presenting symptoms vary and can include non-productive cough, dyspnea, fever, syncope and hemoptysis (3). Patients are often misdiagnosed and initiated on anti-coagulation (3). Limitations arise with diagnostic modalities such as CT imaging as tumor invasion is difficult to distinguish from PE in vascular structures. Tumor invasion can be a primary manifestation but in most reported cases occurs in the setting of known diagnosis of lung cancer. The prognostic significance of invasion into the pulmonary veins is not well studied. Invasion of the pulmonary artery is believed to lead to dissemination into the pulmonary circulation, however invasion into the pulmonary artery portends better prognosis compared to invasion into other mediastinal structures (1). CONCLUSIONS: Although rare in clinical practice, pulmonary vein invasion from extension of primary lung malignancies should be considered in any patient with known lung cancer and new onset filling defects on CTA imaging. This case represents the diagnostic challenges in patients with primary lung malignancies with typical PE symptoms and radiologic findings of thrombosis. Further use with intrapulmonary vascular catheter biopsy or surgical biopsy at the time of presentation is essential to distinguish PE from vascular invasion of malignant disease. Reference #1: 1. Goto, T., Maeshima, A., & Kato, R. (2012). Lung adenocarcinoma with peculiar growth to the pulmonary artery and thrombus formation: report of a case. World journal of surgical oncology, 10(1), 16. Reference #2: 1. 2. Pang, J., Nair, G. B., Ilowite, J., Hoffman, J., & Chawla, S. (2013). An unusual presentation of squamous cell carcinoma of lung in an immunocompromised patient mimicking pulmonary artery embolism. Chest, 144(4), 616A. Reference #3: 1. Çakır, H., Öcal, L., Öcal, A. G., Çakır, H., Akkuş, E. E., & Kahveci, G. (2014). Unusual presentation of a recurrent squamous cell lung cancer. QJM: An International Journal of Medicine, 108(3), 231-232. DISCLOSURES: No relevant relationships by Sara Ali, source=Web Response No relevant relationships by Brandon Hooks, source=Web Response