Malignancy risk for the categories: Non-diagnostic, benign, atypical, suspicious, and malignant used in the categorization of endobronchial ultrasound guided-fine needle aspirates of pulmonary nodules.

BACKGROUND

Endobronchial ultrasound-guided fine-needle aspiration (EBUS-FNA) is frequently used for the workup of pulmonary nodules. While no universally accepted diagnostic classification exists, many cytopathologists use the categories: Non-diagnostic, benign, atypical, suspicious and malignant. Sensitivity and specificity for the EBUS technique have been documented, but little information is available for malignancy risk associated with these categories.

METHODS

Departments of Pathology records at the University of Utah and University of North Carolina, Chapel Hill were searched for EBUS-FNAs of pulmonary nodules. Cases with surgical follow-up were selected. Cytologic diagnosis and subsequent surgical diagnosis were correlated and malignancy risk calculated for each category. Sensitivity and specificity were calculated.

RESULTS

155 EBUS-FNAs with surgical follow-up were obtained. Risks of malignancy were: Non-diagnostic 40%, benign 24%, atypical 54%, suspicious for malignancy 82% and malignant 87%. Sensitivity and specificity were 81% and 84% respectively for surgically confirmed cytologic diagnoses when indeterminate categories were excluded.

CONCLUSION

The diagnostic categories are associated with increasing risk of malignancy running from non-diagnostic to malignant. The non-diagnostic category has a significant risk of malignancy. While the risk of malignancy for a benign diagnosis is substantial (24%), it is significantly less than that associated with an atypical or suspicious diagnosis. A suspicious diagnosis carries a risk for malignancy essentially the same as a malignant diagnosis. The categories atypical and suspicious appear to have substantially different risks for malignancy (54% vs.82%). The atypical category has twice the risk of malignancy as benign. This risk stratification may be useful for patient management.