Cytomorphologic and immunophenotypical analysis of SMARCA4 (BRG1)-deficient non-small cell lung carcinoma

Oluwaseun B. Ogunbona, Xiaoqi Lin, Jason L. Hornick, Daniel J. Lubin, Qun Wang, Michelle D. Reid, Frank Schneider, Dehong Li, Dong M. Shin, Qiuying Shi

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Introduction: Inactivation of SMARCA4/BRG1 (Brahma-related gene 1), a member of the switch/sucrose nonfermentable subfamily of adenosine triphosphate-dependent chromatin remodeling complexes, has been demonstrated in a subset of non–small cell lung carcinomas (NSCLCs). However, the cytomorphologic features of SMARCA4-deficient NSCLCs (SMARCA4-dNSCLC) have only rarely been reported. Materials and methods: Eight cytology cases of SMARCA4-dNSCLC and eight SMARCA4-retained NSCLC (SMARCA4-rNSCLC) cases were retrieved from our institution's database. These were compared cytologically and immunophenotypically. Results: All 8 patients with SMARCA4-dNSCLC had a smoking history, and 4 of 8 cases had a prior cancer history. Cytologically, the tumors demonstrated predominantly loosely cohesive and high-grade epithelioid cells with markedly pleomorphic nuclei and prominent nucleoli. Binucleated/multinucleated cells were seen in 5 cases. Six cases showed focal plasmacytoid morphology, and 2 cases showed necrosis. In contrast, in all 8 cases of SMARCA4-rNSCLC, the aspirates were predominantly cohesive with focal, loosely cohesive epithelioid cells showing mild to moderate pleomorphism and lacked necrosis. Only 1 case showed multinucleated cells. All 8 cases of SMARCA4-dNSCLC showed an immunoprofile similar to that of the SMARCA4-rNSCLC cases, including immunoreactivity for AE1/AE3, a lack of immunoreactivity for thyroid transcription factor-1/Napsin A, and p40/p63 but with a loss of BRG1 expression. Conclusions: SMARCA4-dNSCLCs exhibited high-grade cytologic features with marked pleomorphism and might show multinucleation and plasmacytoid morphology. In contrast, SMARCA4-rNSCLCs often show mild to moderate pleomorphism with round to polygonal shapes. Both characteristically lack expression of lung adenocarcinoma/squamous markers. Increased awareness of their cytomorphologic features on fine needle aspiration can ensure consideration of the diagnosis.

Original languageEnglish (US)
Pages (from-to)183-193
Number of pages11
JournalJournal of the American Society of Cytopathology
Volume11
Issue number4
DOIs
StatePublished - Jul 1 2022
Externally publishedYes

Keywords

  • BRG1
  • Clinicopathology correlation
  • Cytology
  • Immunohistochemistry
  • Non–small cell lung carcinoma
  • SMARCA4

ASJC Scopus subject areas

  • Pathology and Forensic Medicine

Fingerprint

Dive into the research topics of 'Cytomorphologic and immunophenotypical analysis of SMARCA4 (BRG1)-deficient non-small cell lung carcinoma'. Together they form a unique fingerprint.

Cite this