Fine needle aspiration of bone tumors

Fine needle aspiration cytology (FNAC) was performed in 226 cases of bone tumors and the cytohistologic correlation was calculated to assess the technique's diagnostic efficacy aided by immunocytochemistry, considering histopathology as the gold standard. Of the 226 cases, 136 were malignant and 72 cases were benign tumors. In the remaining 18 cases, cytohistopathologic examination revealed no bony lesion. There were 178 evaluable cases, but the specific morphologic diagnosis on FNAC was possible only in 159 cases with one false positive and 29 false negatives. Giant cell tumor (32%) and Ewing's sarcoma (22%) were the most common bony tumors encountered in this series. The diagnostic indices were calculated by a decision matrix comparison. The overall sensitivity and specificity were 86.0 (confidence interval [CI], 80.3-90.3) and 94.7 (CI, 71.9-99.7), respectively. The positive predictive value (PPV) was as high as 99.4 (CI, 96.5-100), while the negative predictive value (NPV) was 38.3 (CI, 24.9-53.6) with positive and negative likelihood ratios of 16.338 and 0.147, respectively. Diagnosis of malignant tumors was more accurate with a PPV of 99.2 (CI, 94.8-100.0) and specificity of 94.7 (CI, 71.9-99.7), while the sensitivity was 89.0 (CI, 82.2-93.5) and NPV was 54.5 (CI, 36.6-71.5). This study highlights the usefulness of FNAC along with the use of immunocytochemistry in the rapid diagnosis of bone tumors.