Impact of immediate evaluation of touch imprint cytology from computed tomography guided core needle biopsies of mass lesions: Single institution experience.

Background: Computed tomography (CT) guided core needle biopsy (CT-guided CNB) is a minimally invasive, safe and effective manner of tissue sampling in many organs. The aim of our study is to determine the impact of on-site evaluation of touch imprint cytology (TIC) to minimize the number of passes required to obtain adequate tissue for diagnosis.

Design: A retrospective review of all CT-guided CNBs performed during 4 year period, where pathologists were present for on-site TIC evaluation. Each case was evaluated for the number of passes required before TIC was interpreted as adequate for diagnosis.

Results: A total of 140 CT-guided CNBs were included in the study (liver, lung, kidney, sacral, paraspinal, omental, splenic and adrenal masses). Of the 140 cases, 109 were diagnosed as malignant, 28 as benign and three insufficient. In 106 cases (75.7%), the biopsies were determined adequate by TIC on the first pass, 19 cases (13%) on the second pass and 7 cases (5%) on the third pass. Only in 5 cases (3.6%), more than three passes were required before diagnostic material was obtained. Three cases (2.14%) were interpreted as inadequate both on TIC and on the final diagnosis. Of the biopsies deemed adequate on the first pass, 71% resulted in either termination of the procedure, or only one additional pass was obtained. In five cases, based on the TIC evaluation, a portion of the sample was sent for either flow cytometric analysis or cytogenetic studies.

Conclusions: In the majority of cases, adequate material was obtained in the first pass of CT-guided CNB and once this was obtained, either no additional passes, or one additional pass was performed. This study demonstrates the utility of on-site evaluation in minimizing the number of passes required for obtaining adequate diagnostic material and for proper specimen triage for ancillary studies, which in turn decreases the risk to the patient and costs. However, tumor exhaustion in the tissue as a result of TIC is an important pitfall of the procedure, which occurred in 9 (8.2%) of our malignant cases.