Fine-needle aspiration biopsy of vertebral and intervertebral disc lesions: specimen adequacy, diagnostic utility, and pitfalls.

BACKGROUND AND

OBJECTIVES

Fine-needle aspiration biopsy (FNAB) is used extensively in the clinical workup of radiologically detected bony lesions. The aims of this study were to evaluate the diagnostic utility of FNAB of such radiologically detected vertebral and intervertebral disc lesions in patients with and without a known primary malignancy, to establish criteria for specimen adequacy, and to evaluate the diagnostic pitfalls.

DESIGN

The cytologic material obtained by FNAB performed under computed tomographic guidance of 78 cases comprising 66 vertebral and 12 intervertebral disc lesions was reviewed and analyzed. The initial cytologic diagnosis was compared with the diagnosis after review in all 78 cases.

RESULTS

Thirty-five cases (45%) were positive for malignancy, 1 case (1.3%) was suspicious for malignancy, 9 (11.5%) consisted of normal cellular elements with no evidence of malignancy, 21 (27%) were unsatisfactory/inadequate for diagnosis, and 12 (15.2%) were benign nonneoplastic lesions. Nonneoplastic lesions diagnosed included fracture callus, discitis/osteomyelitis, degenerative disc disease, and Paget disease. In 11 cases, FNAB gave the initial diagnosis of malignancy (8 occult carcinomas and 3 plasmacytomas). In 23 out of 36 cases with a clinical history of a known primary tumor, FNAB established the diagnosis of metastases, and in 1 case, a second primary was detected.

CONCLUSIONS

Fine-needle aspiration biopsy of radiologically suspected vertebral and intervertebral disc lesions in patients with a history of a known malignancy is useful to confirm the presence of metastases. In cases without any history of malignancy, FNAB can provide additional clues to aid in the subsequent workup and treatment of cases diagnosed with an unsuspected malignancy and other nonneoplastic lesions. Through assessment of the specimen adequacy, correct interpretation of the cytologic material available, and correlating with the clinical and radiologic findings, a definitive diagnosis can be made in most cases.