A case of mistaken identity: persistent pulmonary embolism symptoms prompt a secondary investigation

SESSION TITLE: Lung Cancer: Rare Malignancies Presenting in the Lung SESSION TYPE: Case Reports PRESENTED ON: 10/09/2023 01:00 pm - 02:00 pm INTRODUCTION: There are rare diagnoses often mistaken for an unresolving pulmonary embolism (PE). We present a rare mimicker of a PE, that is often found postmortem and requires unique management. CASE PRESENTATION: A 53-year-old woman presented to the ED reporting chest pain for two weeks. With an elevated D-dimer, a CT scan was performed showing a large right interlobar PE with extension to distal branches and pulmonary infarct. She was diagnosed with an unprovoked PE and initiated on rivaroxaban. After discharge, she returned periodically to the hospital and pulmonary clinic with persistent chest pain, exertional dyspnea without hypoxia and near-syncopal episodes where it was noted she had persistent radiographic filling defects despite two months of therapy. An expanded workup was launched to evaluate for chronic thromboembolic disease (CTED), primary pulmonary vascular malignancy, or hematologic disease. PFTs showed normal spirometry and lung volumes with mildly reduced diffusion capacity. VQ scan was consistent with chronic PE in the right middle and lower lobes. TTE showed normal biventricular function. A pulmonary angiogram demonstrated normal right heart hemodynamics but a perfusion cutoff in the right lower lobe. She was referred for pulmonary thromboendarterectomy and thoracic surgery evaluation for CTED. Eighteen months after initial imaging, a PET scan showed an enlarging soft tissue mass (SUV 16.3) within the right pulmonary artery and its branches. Bronchoscopy observed right middle lobe endobronchial mucosal abnormalities with transbronchial needle aspirations showing malignant spindle cells consistent with sarcoma. Two years after her initial symptom-onset, she underwent radical intrapericardial right pneumonectomy en-block with pericardial resection. Surgical pathology confirmed a 7.0 cm high grade intimal sarcoma of the right main pulmonary artery with extension into the pulmonary vein and right main stem bronchus. After surgery, surveillance PET showed residual perihilar disease, and she is currently undergoing adjuvant immunotherapy and radiation. DISCUSSION: Primary pulmonary artery sarcoma (PPAS) has an incidence of 0.001% - 0.03% with a median survival of 26.8 months – 36.5 months after complete resection. Increased odds of death are associated with delays in diagnosis, local recurrence, and distant metastasis. It is a life-threatening malignancy that is often misidentified as a PE with its radiographic findings and symptom presentation with dyspnea, cough, chest pain, and hemoptysis. Misdiagnosis delays definitive treatment with pulmonary endarterectomy, full-thickness resection, or pneumonectomy. Our case is a reminder to reevaluate a persistently symptomatic patient with an unresolving pulmonary vascular filling defect for alternative pathologic processes. CONCLUSIONS: There are no guidelines for sequential imaging after a PE. An astute recognition of persistent symptoms should prompt secondary investigation for pulmonary vascular malignancy, such as PPAS, to avoid delayed diagnosis. REFERENCE #1: Bandyopadhyay, D, et al. Primary pulmonary artery sarcoma: a close associate of pulmonary embolism—20-year observational analysis. J Thoracic Disease. 2016. 8(9):2592-2601. REFERENCE #2: Ropp, A., et al. Intimal Sarcoma of the Great Vessels. Radiographics.rsna.org. 2021. 41(2): 361-379. REFERENCE #3: Hassler, K, et al. Pulmonary Artery Sarcoma Complete Resection Facilitated by 3-Dimentional Printed Model. Ann Thoracic Surg. 2021. 114:e375-e378. DISCLOSURES: No relevant relationships by Lily Cheng No relevant relationships by Jenny Han No disclosure on file for Jordan Kempker Clinical Trial Monitoring Board relationship with Genentech Please note: 2020-2021 by Greg Martin, value=Consulting fee Removed 03/15/2023 by Greg Martin, source=Web Response Scientific Medical Advisor relationship with Grifols Please note: 2019- by Greg Martin, value=Consulting fee Scientific Medical Advisor relationship with Beckman Coulter Please note: 2022- by Greg Martin, value=Consulting fee