Incidental pulmonary nodules detected on abdominal computed tomography

To review the characteristics and outcome of incidental pulmonary nodules reported on abdominal computed tomography (CT).

A database search of abdominal CTs from January 1, 2004, to December 31, 2006, revealed 413 patients with incidental pulmonary nodules and at least one follow-up chest CT. Demographic information, nodule characteristics, and eventual outcome of the nodules were analyzed.

Of the 413 patients, 56% had benign nodules, 11% had malignant nodules, and the remaining 33% had insufficient follow-up. There was a statistically significant difference (P < 0.05) in the age of the patients, history of malignancy, and size of the incidental nodule between benign and malignant groups. No malignant nodules were found in patients younger than 59 years who did not have a known or suspected malignancy.

Small pulmonary nodules (<8 mm) on abdominal CT in patients younger than 50 years with no history of malignancy are unlikely to be malignant.