Ancillary Studies in FNAC of Soft Tissue and Bone Lesions

Diagnostic benefits and cost-effectiveness of on-site imprint cytology adequacy evaluation of core needle biopsies of bone lesions

BACKGROUND

Core needle biopsy (CNB) is a well-established, successful technique for the diagnosis of various organ system lesions. To increase diagnostic yield, on-site cytologic evaluation of adequacy (OCA) is routinely performed at many institutions. Numerous studies evaluating the impact of OCA on CNB have been published. However, little has been said regarding accuracy of OCA for bone lesions.

METHODS

To evaluate this, we reviewed our experience during a two-year period, and compared OCA results with the final diagnosis of the corresponding CNB. For the study, diagnoses were divided into three categories: malignant, benign, and nonspecific/nondiagnostic findings.

RESULTS

Sixty-one cases were included. During OCA, 25 cases were diagnosed as malignant, three cases as benign, and 33 as nonspecific/nondiagnostic. On histologic evaluation, 29 cases were malignant, 16 were benign, and 16 were classified as nonspecific/nondiagnostic. Concordance with final CNB diagnosis was seen in 100% of malignant, 67% of benign, and 45% of nonspecific/nondiagnostic on-site cytology evaluations. The overall diagnostic success rate of OCA for malignancy was 86% (25/29). The success rate of OCA for benign lesions was only 13%. Fifty-four percent of cases were diagnosed as nonspecific/nondiagnostic on-site. This category included four false negative cases.

CONCLUSIONS

We conclude that for lesions with a suspicion of malignancy, OCA is a valuable adjuvant diagnostic tool. However, for cases with a benign or nonspecific clinical impression, OCA has a limited diagnostic role. Careful selection of cases in which OCA is beneficial is necessary to maintain accuracy and to limit procedure costs.