Core wash cytology of breast lesions by ultrasonographically guided core needle biopsy.

Previous studies demonstrated that core wash cytology by stereotactic needle biopsy was useful for the immediate diagnosis of breast lesions. The purpose of this study was to assess the accuracy of core wash cytology of breast lesions by ultrasonographically (US) guided core needle biopsy (CNB). US-guided 18-gauge CNB was performed in a series of 458 cases. Each CNB sample was washed in saline solution. Core wash cytology of the washed core material was performed on material obtained by saline solution lavage of the fragments using a cytocentrifuge. The cytological diagnoses were divided into five categories: benign, atypical/indeterminate, suspicious/probably malignant, malignant, and unsatisfactory, which then were compared with the CNB results. The cytological diagnoses of the 458 cases were as follows: 106 lesions (23.1%) were benign, 28 lesions (6.1%) were atypical/indeterminate, 42 lesions (9.2%) were suspicious/probably malignant, 88 lesions (19.2%) were malignant, and 194 lesions (42.4%) were unsatisfactory. The core wash cytology had a sensitivity of 89% (141 of 158), and a specificity of 72% (76 of 106). The CNB showed 143 of 194 unsatisfactory samples (74%) to be benign, three to be high-risk, and 48 (25%) to be malignant. Unsatisfactory samples were obtained from significantly more benign than malignant lesions. In conclusion, the high rate of insufficient samples for core wash cytology of breast lesions by US-guided CNB makes its use impractical in this setting. This technique is not useful for immediate diagnosis of breast lesions by US-guided CNB.