biostudies-literatureKezlarian BNCI NIH HHS526-534https://www.ebi.ac.uk/biostudies/studies/S-EPMC11037264biostudies-literatureUnknown131(8)<h4>Introduction</h4>Although alterations in SMARCA4-deficient occur in non-small cell lung carcinoma (SD-NSCLC), thoracic SMARCA4-deficient undifferentiated tumor (TSDUT) is recognized as a distinct entity in the 2021 World Health Organization Classification of Thoracic Tumors because of unique morphologic, immunophenotypic and molecular features, and worse survival compared with SD-NSCLC. Cytologic diagnosis of TSDUT is clinically important because of its aggressive behavior and because it is often diagnosed by fine-needle aspiration because TSDUTs are usually unresectable at presentation. Here, we identify cytologic features that can be used for recognition of TSDUT and distinction from SD-NSCLC.<h4>Materials and methods</h4>Cytomorphologic features were investigated in cytology specimeCancer cytopathologyDiagnosis of thoracic SMARCA4-deficient undifferentiated tumor in cytology.PMC11037264P30 CA008748White CSauter JLRiedel EKezlarian BMontecalvo JBodd FMChang JCRekhtman NfalseDiagnosis of thoracic SMARCA4-deficient undifferentiated tumor in cytology.<h4>Introduction</h4>Although alterations in SMARCA4-deficient occur in non-small cell lung carcinoma (SD-NSCLC), thoracic SMARCA4-deficient undifferentiated tumor (TSDUT) is recognized as a distinct entity in the 2021 World Health Organization Classification of Thoracic Tumors because of unique morphologic, immunophenotypic and molecular features, and worse survival compared with SD-NSCLC. Cytologic diagnosis of TSDUT is clinically important because of its aggressive behavior and because it is often diagnosed by fine-needle aspiration because TSDUTs are usually unresectable at presentation. Here, we identify cytologic features that can be used for recognition of TSDUT and distinction from SD-NSCLC.<h4>Materials and methods</h4>Cytomorphologic features were investigated in cytology specime2023-01-01T00:00:00Z2023 Aug2025-04-19T20:45:38.594Z2025-04-19T20:45:38.594ZS-EPMC110372643727810210.1002/cncy.22709