Core wash or touch imprint cytology is often used to obtain a quick, preliminary diagnosis on a core needle biopsy (CNB) of breast lesions, essential for the management of the 1-day breast clinic. Contradictory results of both techniques in the literature led to this preclinical study investigating an alternative method of touch imprint and core wash cytology.
Thirty breast lesions were biopsied by a core needle in a laboratory setting. The CNBs were collected in RPMI fluid (Roswell Park Memorial Institute fluid). The touch imprint cytology was performed taking the biopsy out of the fluid and smearing it on a microscopic slide and May-Grunwald Giemsa stained. The core wash cytology was made by fixating the remaining cells in Fixcyt and prepared with a liquid-based preparation method and Papanicolaou stained. The cytologic findings were categorized into benign, atypical favoring benign, atypical, suspicious, and malignant and compared with the histologic CNB results.
The CNBs showed 20 of 30 samples to be malignant, 2 to be phylloides tumors, 7 to be benign, and 1 to be unsatisfactory. Both techniques showed a sensitivity of 95% and specificity of 100%. Touch imprint yielded insufficient diagnoses (13.3%), compared with core wash (6.6%). Of the core wash cases, 86% showed a good quality versus 30% in touch imprint cytology.
This preclinical study on modified touch imprint and core wash techniques led to results that were comparable to or better than those in the literature. The core wash cytology is preferred to touch imprint because of the better morphology.