Combined radiology and cytology in the diagnosis of bone lesions: a retrospective study of 370 cases.

Background: Some of the risks with open biopsy can be avoided by fine-needle aspiration biopsy. The diagnostic contribution of radiologic findings has not been systematically studied.

Patients and methods: We retrospectively analyzed the validity of combined radiology and fine-needle aspiration cytology for the diagnosis of bone lesions in a consecutive series of 370 patients. The treatment diagnosis was based solely on radiology and cytology in 234 cases, whereas in 136 cases histopathology was also applied.

Results: Comparison of radiology and cytology showed diagnostic compliance in 256 cases (69%) and non-compliance in 101 (28%). 13 (3%) cases failed to yield diagnostic material for cytology. Among the 256 compliant cases, the diagnostic error rate was 1% (2 were falsely benign), whereas the corresponding rate was 17% among the 101 non-compliant cases. In the latter group, 36 cases yielded only normal cells at aspiration, out of which 20 proved to have a neoplastic lesion (8 metastases, 12 benign). The overall sensitivity of cytology alone in recognizing malignancy was 90%. The specificity was 95%. Given a malignant or benign diagnosis, the positive predictive value was 97% and the negative predictive value was 84%.

Interpretation: Our study suggests that a simple approach based on conventional radiography and fine-needle aspiration cytology offers a valid means of diagnosing bone lesions. Provided there is compliance between radiology and cytology, the risk of false diagnosis is around 1%.