A solitary pulmonary nodule is defined as a relatively round lesion that is <3 cm in diameter and completely surrounded by lung parenchyma. It is distinct from lung lesions >3 cm in diameter, which are considered lung masses. Traditionally, the definition of solitary pulmonary nodule has also excluded a ground-glass infiltrate seen on computed tomography (CT) scan, as this finding is commonly associated with bronchoalveolar cell carcinoma and does not fulfil the physical characteristics of a nodule.  For the purposes of this topic, we will consider ground-glass opacities as solitary pulmonary nodules.
The goals in managing a patient with a solitary pulmonary nodule are to distinguish the benign from the malignant nodule and, when malignancy is either confirmed or strongly suspected, to expedite resection.
For solitary pulmonary nodules, established clinical features (e.g., patient age, smoking status) and radiographic findings (e.g., calcification, growth rate, size) help determine a probability of malignancy. If necessary, non-invasive and/or invasive testing is used to more accurately determine the probability of malignancy to a level that enables a decision to be made regarding observation or resection. Therefore, the proper use of these tests mandates knowledge about their performance characteristics. Decision analysis approaches using Bayesian methods may also assist with the calculation of the probability of malignancy, although these methods have not consistently outperformed the clinical assessment and testing approach. 
Chief, Complex Chest Disease Center
Co-director, Interventional Pulmonology Massachusetts General Hospital
Harvard Medical School
EEF is the global principal investigator for the NAVIGATE trial, sponsored by Medtronic. He has also served as scientific consultant for Boston Scientific in the development of advanced bronchoscopic techniques.
Director of Lung Cancer Program
Director of Lung Cancer Screening Program
Director of Education
PJM has been paid to participate in clinical advisory board meetings for Oncimmune, InDi, Nucleix, Grail, and Oncocytelooking, all companies interested in developing molecular biomarkers for the evaluation of lung nodules/ lung cancer; he does not have a contractual agreement to disseminate product information for any of these companies. PJM has participated in research supported by InDi Veracyte, that was paid to his institution. He has also participated in research with in-kind support from Oncimmune and 20/20 Genesystems.
Royal Brompton Hospital
Chelsea & Westminster Hospital
PLS declares that he has no competing interests.
Associate Professor of Medicine
Lung Transplant Program
University of Chicago Hospitals
SMB declares that she has no competing interests.
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