Silent but suspicious: the clinical significance of slowly expanding PET-negative lung nodules.

backgroundSolitary fibrous tumor (SFT) is a rare benign neoplasm arising from fibrous connective tissue of the lung. These tumors are often asymptomatic and incidentally detected, but their radiologic appearance may resemble malignancies. CASE PRESENTATION: A 42-year-old male, former smoker, presented for routine post-COVID-19 imaging. Incidentally, a 38 × 35 mm pulmonary mass was discovered posterior to the left pulmonary artery. The patient was asymptomatic, and physical exam findings were unremarkable. Initial CT and MRI suggested a benign lesion with no PET/CT radiotracer uptake. Despite initial radiological stability, the lesion demonstrated interval growth over 2.5 years, prompting video-assisted thoracoscopic surgical resection. Histopathology confirmed a SFT.

conclusionsThis case highlights the diagnostic challenges associated with slowly enlarging pulmonary masses that appear benign on imaging. It underscores the importance of long-term radiological surveillance and timely surgical evaluation when progressive growth is observed, even in PET-negative lesions, to prevent potential complications and definitively exclude malignancy.