NOVEL USE OF EBUS-IFB TO DIAGNOSE SOLITARY FIBROUS TUMORS OF THE PLEURA

Abstract

TOPIC: Procedures TYPE: Fellow Case Reports INTRODUCTION: Endobronchial ultrasound-guided intranodal forceps biopsy (EBUS-IFB) is a novel technique that allows higher yield sampling than fine-needle aspiration (FNA) [1]. We present a case of the EBUS-IFB technique utilized to diagnose a posterior mediastinal solitary fibrous tumor of the pleura. CASE PRESENTATION: A 50-year-old male with tobacco dependence and asbestos exposure presented intoxicated and complained of assault, prompting trauma evaluation. CT chest found an incidental 7.4 cm heterogeneously enhanced mass within the right upper posterior hemithorax abutting the mediastinum. The patient endorsed chronic back pain, cough, and weight loss. Our approach consisted of EBUS-FNA with a 19 gauge needle followed by EBUS-IFB. Immunohistochemistry demonstrated CD34, Vimentin, and signal transducer and activator of transcription 6 (STAT6) protein positive neoplastic cells with a final diagnosis of solitary fibrous tumors of the pleura. DISCUSSION: Solitary fibrous tumors are rare mesenchymal tumors (SFTP) with fibroblastic differentiation characterized by NAB2-STAT6 gene fusion on chromosome 12. NAB2-STAT6 fusion protein drives the nuclear entry of STAT6 protein, facilitating the discrimination between solitary fibrous tumors and histologically similar tumors. EBUS-FNA does not produce high yield results for SFTP [2]. In our case, small mini-forceps were passed into a targeted mass following EBUS-FNA needle puncture, and we obtained adequate tissue to make a successful diagnosis. To our knowledge, this is the first case EBUS-IFB applied to a posterior mediastinal SFTP. CONCLUSIONS: Our case demonstrates the novel use of EBUS-IFB to diagnose paraspinal SFTP. This technique provides a less invasive alternative from surgical biopsy to aid in the diagnosis of SFTP. REFERENCE #1: J Thorac Dis. 2019 Sep;11(9):4049-4058. REFERENCE #2: Curr Opin Pulm Med. 2012 Jul;18(4):339-46 DISCLOSURES: No relevant relationships by Kenneth D'Souza, source=Web Response No relevant relationships by Reiichiro Obata, source=Web Response no disclosure on file for Muhammad Perwaiz