Fine-needle aspiration biopsy in the diagnosis and management of bone lesions: a study of 450 cases.

BACKGROUND

Fine-needle aspiration (FNA) biopsy has proved to be a cost-effective technique, with low complication risks and high diagnostic value in distinguishing neoplastic versus nonneoplastic lesions in many organs. This study was designed to determine the reliability, areas of diagnostic difficulty, and limitations of FNA in the diagnosis of bone lesions encountered in a university-affiliated tertiary care hospital.

METHODS

The cytology of 450 FNA biopsies of bone lesions, performed on 427 patients between 1979 and 1996, were reviewed. The results were correlated with the corresponding histology when available, and with clinical follow-up, in an attempt to define the role of FNA in managing patients with bony lesions.

RESULTS

The patients ranged in age from 5 to 94 years, with a male-to-female ratio of 1.25:1. The spine was the most frequently aspirated site (49%), followed by the ilium, sacrum, mandible, ribs, and femur. Three hundred and eighty-five aspirates (86%) were adequate for evaluation, with 215 cases diagnosed cytologically as positive for malignancy, 11 cases as suspicious but not diagnostic of malignancy, and 2 cases as inconclusive. One hundred and fifty-seven cases were interpreted as showing no evidence of malignancy. Metastatic carcinoma was present in 175 of the 215 malignant aspirates, and 67% of these were adenocarcinomas. Forty cases were primary malignant bone neoplasms, including myeloma, lymphoma, Ewing's sarcoma, chondrosarcoma, ameloblastoma, chordoma, neurofibrosarcoma, and unclassified high grade sarcoma. False-negative diagnoses were rendered in ten cases; however, on review, material representative of the bone lesion was not present in six cases. Five cases were correctly diagnosed as malignant but were misclassified with regard to the type of malignancy.

CONCLUSIONS

FNA biopsy of bone lesions is a reliable and easily performed diagnostic test for metastatic and primary bone tumors. False-positive results have major therapeutic implications, hence the significance of the authors' conservative diagnostic approach, which resulted in a false-positive rate of 0.2%. Areas of difficulty were due to inadequate sampling or misclassification with regard to the exact type of malignancy. The simplicity and accuracy of this procedure, which does not require any surgical incisions (open biopsy or manipulation), supports its important role in triaging and managing bone lesions with minimum risk or morbidity.