Core needle biopsy in benign lung lesions: pathologic findings in 159 cases.

Although core needle biopsy has been shown to be an accurate means of diagnosing lung malignancies, there is relatively little information in the literature about its utility in diagnosing specific non-malignant conditions. We reviewed the pathologic findings in 159 core needle biopsies showing benign changes in order to determine the types of processes that can be diagnosed by this technique and the factors that influence accuracy and specificity. There were 155 patients ranging in age from 3 to 86 years (mean 58). Nodules or masses were present radiologically in most. They ranged from 0.5 to 8.0 cm (mean 1.65 cm) in size and 80% measured 2.0 cm or less. Twenty percent were spiculated, and positron emission tomography scans were positive in 48 of 56 cases tested (30% of total). Specific diagnoses were established in 122 (77%) of 159 core needle biopsies, while 24 (15%) were nonspecific and 13 (8%) were nonrepresentative. The most common specific diagnoses were necrotizing granulomatous inflammation (45), scar (28), organizing pneumonia (13), and benign neoplasms (11). A mixture of interstitial fibrosis and chronic inflammation (16) was the most common nonspecific diagnosis. A specific diagnosis was significantly more likely in biopsies with 3 or more cores or with a core length of more than 1 cm. Malignancy was diagnosed on a subsequent biopsy in only one case, and the initial biopsy in that case showed non-specific chronic inflammation and fibrosis. Our findings confirm that core needle biopsy is an accurate method of diagnosing benign lung lesions, yielding specific diagnoses in the majority.