Background: Lesions detected by positron emission tomography-computed tomography (PET-CT) during the analysis of thoracic tumours are often impalpable at physical examination, and subsequent ultrasound (US) may aid in finding these lesions for pathologic evaluation.

Objectives: The success rate of percutaneous US-guided biopsies of palpable and non-palpable lesions and the impact on tumour stage were studied prospectively.

Methods: Lesions, significant for diagnosis and disease stage, with metabolic activity on PET-CT and presumed appropriate for percutaneous approach under US guidance were selected for cytologic aspiration or tissue core biopsies.

Results: In 127 patients, 134 lesions (subdivided into 24 local thoracic, 74 supraclavicular and 36 distant metastatic lesions) were biopsied percutaneously under US guidance. Malignancy, benign disease and inadequate biopsies were found in 80% (106/134), 14% (19/134) and 7% (9/134), respectively. In 55% (56/102) of patients, biopsies confirmed the disease stage. Fifty-one percent (18/35) of distant lesions and 54% (43/68) of supraclavicular lesions were impalpable on physical examination.

Conclusions: US-guided biopsies in patients with suspected thoracic malignancy on PET-CT provide an excellent tool for obtaining a pathological diagnosis, leading to a definitive disease stage in over half of the patients.