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SMARCA4‑deficient non‑small cell lung cancer with an EGFR mutation: A case report
Lijun Sun1, Qiong Fu1, Lijiang Chen1
1Department of Pathology, Xiaoshan Affiliated Hospital of Wenzhou Medical University, Hangzhou, Zhejiang 311200, P.R. China.
Abstract:
SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily a, member 4 (SMARCA4)-deficient non-small cell lung cancer (dNSCLC) is a rare malignant tumor that originates in the lungs. It occurs more frequently in male smokers, and the epidermal growth factor receptor (EGFR) gene is often mutation-free. In the present study, the case of a 60-year-old, non-smoking female patient diagnosed with SMARCA4-dNSCLC is reported. Biopsy of the tumor showed solid flaky, nest-like infiltrating growth. Immunohistochemistry revealed the following: SMARCA4/BRG1(-), SMARCB1/INI-1(+), cytokeratin7 (+), cytokeratin 5.2 (+), CK5/6(+) and calretinin(+). The Ki-67 positivity index was 75%, and the thyroid transcription factor-1, NapsinA, p40, nuclear protein in testis, CD34, Sal-like protein 4, SRY-box transcription factor 2 and synaptophysin were negative. Molecular analysis showed mutations in both EGFR and TP53. The pathological diagnosis was SMARCA4-dNSCLC with an EGFR gene mutation. The present case report could be used for broadening the pathological diagnosis of SMARCA4-dNSCLC and for selecting appropriate treatment approaches.
Insights
This case report details a rare SMARCA4-deficient non-small cell lung cancer (dNSCLC) in a non-smoking female. The findings highlight the importance of comprehensive molecular analysis for diagnosing SMARCA4-dNSCLC, even with EGFR mutations.
Area of Science:
- Oncology
- Genetics
- Pathology
Background:
- SMARCA4-deficient non-small cell lung cancer (dNSCLC) is a rare subtype, typically affecting male smokers with no EGFR mutations.
- Understanding the diverse presentations of dNSCLC is crucial for accurate diagnosis and treatment.
Observation:
- A 60-year-old non-smoking female presented with SMARCA4-dNSCLC.
- Tumor biopsy revealed solid, flaky, nest-like infiltrating growth.
- Immunohistochemistry showed SMARCA4/BRG1 negativity, with positive markers for cytokeratin7, cytokeratin 5.2, CK5/6, and calretinin. Ki-67 index was 75%.
Findings:
- Molecular analysis identified mutations in both EGFR and TP53 genes.
- The pathological diagnosis confirmed SMARCA4-dNSCLC with an EGFR mutation, challenging typical presentations.
- Immunohistochemical profile indicated a distinct subtype of dNSCLC.
Implications:
- This case expands the known pathological spectrum of SMARCA4-dNSCLC.
- Accurate diagnosis through comprehensive molecular and immunohistochemical analysis is vital for targeted therapy selection.
- Further research into rare dNSCLC subtypes with EGFR mutations is warranted.
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