Frequency and rationale of fine needle aspiration biopsy conversion to core biopsy as a result of onsite evaluation

OBJECTIVE: To measure the frequency and analyze the rationale and potential diagnostic benefits of converting the fine needle aspiration (FNA) procedure to core biopsy. STUDY DESIGN: The frequency of conversion to core biopsy was calculated over 13 months. Analysis of these cases was conducted in regard to the appropriateness for conversion and whether the core biopsy provided additional specific diagnostic information. RESULTS: During this period, the onsite triaging pathologist recommended FNA conversion to core biopsy in 31 of 821 procedures (3.7%). In 3 instances, the core biopsy could not be performed. The rationale for conversion in the remaining 28 cases (3.4%) included either scant aspirated material in 9 cases (32%) or an anticipated need for additional histologic material to further characterize the lesion in the other 19 (68%). In 27 cases (96%), the rationale for conversion was considered to be appropriate, and in 3 of these (11%) the core provided a change in diagnosis. Additional useful diagnostic information was identified in 12 cases (44%). CONCLUSION: Conversion to core biopsy during FNA is infrequent but justified in most cases. Appropriate utilization of this approach is helpful and may be cost effective.