CT Imaging Spectrum of SMARCA4-Deficient Non-Small Cell Lung Cancer: A Descriptive Case Series of 32 Patients

Background SMARCA4-deficient non-small cell lung cancer (SMARCA4-dNSCLC) is a rare primary malignant epithelial tumour of the lungs. This study aimed to characterize the CT imaging findings and clinical features of SMARCA4-dNSCLC in a descriptive case series Methods The CT findings and clinical data from 32 patients with histologically confirmed SMARCA4-dNSCLC treated at Hainan General Hospital from September 2022 to August 2024 were retrospectively analysed. CT findings included location, size, density, presence of the lobulated and speculated sign, internal features, surrounding conditions, and pleural and/or pericardial effusion. Results Among the 32 patients, the age ranged from 33 to 84 years (median 63 years, average 63.6 ± 11 years); 28 were male (87.5%), and 4 were females (12.5%); Thirty-one patients presented with pulmonary nodules and masses (96.9%), among whom 25(78.1%) had peripherally. The tumour size ranged from 9 to 123 mm (median 34 mm, average 38.8 ± 23.4 mm). The tumour composition was solid in 28 patients (90.3%). Twenty-nine patients had the lobulated sign (93.5%), 18 had the spicule sign (58.1%), 15 had necrosis (48.4%) and 24 had the pleural contact sign (77.4%). Sixteen patients had mediastinal and hilar lymph node metastases (50%), and 21 had distant metastases (65.6%). Conclusion SMARCA4-dNSCLC was predominantly observed in elderly men with a heavy smoking history. On CT, the tumors commonly presented as large solid peripheral masses, usually found in the upper lobes of both lungs, with internal necrosis, lobulation, spiculation, and pleural contact. The tumours exhibit rapid growth (mean volume doubling time 55.8 days), with metastasis being common at presentation.