A solitary pulmonary nodule (SPN) is defined as a single intraparenchymal lesion less than 3 cm in size and not associated with atelectasis or lymphadenopathy.
A lesion greater than 3 cm in diameter is called a mass.
This distinction is made, because lesions greater than 3 cm are usually malignant, while smaller lesions can be either benign or malignant.
Swensen et al studied the relationship between the size of a SPN and the chance of malignancy in a cohort at high risk for lung cancer (1).
Their findings are listed in the table on the left.
They concluded that benign nodule detection rate is high, especially if lesions are small.
Of the over 2000 nodules that were less than 4 mm in size, none was malignant. #EBM #Radiology #Pulmonary #SolitaryPulmonaryNodule #MalignancyRisk #Malignancy #MalignancyRate #Rate #RadiologyAssistant