A CASE OF IDENTITY: A LUNG MASS WITH SMARCA4 DEFICIENCY

TOPIC: Lung Cancer TYPE: Medical Student/Resident Case Reports INTRODUCTION: SMARCA4 (SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily A, member 4) gene loss in non-small cell lung cancer (NSCLC) has been documented for the last 20 years but is only recently being recognized as a distinct NSCLC subset. Currently, there limited data on its morphologic description, diagnostic criteria, response to therapy, and prognosis [1]. We describe patient presenting with mass brain metastasis who was diagnosed SMARCA-4 undifferentiated carcinoma which an aggressive rare tumor best described so far at GI sites. CASE PRESENTATION: Our forty-seven-year-old Caucasian male 30 pack-year smoking history presented hospital complaints chronic cough, hoarse voice, dysphagia, right-hand weakness. CT head CTA neck revealed multiple lesions right upper lobe mass. chest showed large 7.6 x 6.7 8.6 cm apex peripheral enhancement central low density occluding bronchi apical segment extension into mediastinum mediastinal lymphadenopathy. MRI 11 diffuse lesions, ranging from 6-17 mm size suggestive metastatic disease. The largest lesion located left inferior frontal gyrus had vasogenic edema resulting effect 6 left-to-right midline shift. Subsequently, he underwent craniotomy resection his lesion. also bronchoscopy endobronchial ultrasound (EBUS) transbronchial needle aspiration (TBNA) 4R lymph nodes. Preliminary tissue reports poorly differentiated adenocarcinoma. Pathology epithelioid cells copious pale or eosinophilic cytoplasm, irregular vesicular nuclei, nuclear pleomorphism. It strongly positive pan keratin, negative SOX10, OCT3/4, TTF, SMARCA4, indicating product this Swi/Snf complex. This next-generation sequencing program death ligand-1 (PDL-1) expression subsequent immunotherapy DISCUSSION: Thoracic newly entity cancer. strong predilection towards young males history. Patients present large, infiltrative, compressive thoracic masses associated cervical lymphadenopathy, brain, bones, adrenal glands, have poor prognosis. therapy deficient tumors not yet codified enhancer zeste homolog 2 (EZH2) inhibitors shown be effective reported cases.[ 2] CONCLUSIONS: case adds repository sheds light their clinicopathological presentation diagnosis. REFERENCE #1: Nambirajan Singh V, Bhardwaj N, Mittal S, Kumar Jain D. SMARCA4/BRG1-Deficient Non-Small Cell Carcinomas: A Series Review Literature. Arch Pathol Lab Med. 2021 Jan 1;145(1):90-98. doi: 10.5858/arpa.2019-0633-OA. PMID: 33367658. #2: Chatzopoulos K, Boland JM. Update genetically defined neoplasms: NUT SMARCA4-deficient tumors. Virchows Arch. 2021;478(1):21-30. doi:10.1007/s00428-020-03011-3 DISCLOSURES: No relevant relationships by Sukhmani Boparai, source=Web Response Prangthip Charoenpong, Deon Ford, Aswani Thurlapati,