Sonography of Postexcision Specimens of Nonpalpable Breast Lesions: Value, Limitations, and Description of a Method

The objective of our study was to retrospectively review our experience regarding the value of sonography in identifying a nonpalpable mass within a surgically excised specimen and in assessing the surgical margins in cases of malignancy. One hundred four lumpectomies were performed in 99 consecutive patients with 131 nonpalpable breast lesions after sonographically guided needle localization. All 104 surgical specimens were scanned on sonography, and 86 specimen radiographs were obtained. Visualization of the lesion on sonography was compared with specimen radiographs and histologic findings. Sonographic margin status was classified as negative (shortest distance between tumor and specimen margin, > 0.2 cm) or positive (shortest distance between tumor and specimen margin, 0.2 cm) and was compared with pathology results. Specimen sonography showed 95.4% (125/131) of the excised abnormalities; nonfatty background and a lesion size of greater than 0.5 cm contributed significantly to the success of specimen sonography. Four of six lesions missed on sonography were identified on specimen radiography. Among 81 malignant specimens, sonography identified 38 specimens with positive margins and 43 with negative margins. Pathologic examination revealed eight false-positive and 10 false-negative results (21% false-positive rate and 23.2% false-negative rate). Specimen sonography is an effective procedure for identifying the presence of the lesion within the specimen; however, it is of limited value in cases of small hypoechoic lesions against a fatty background. Assessment of margins is limited by both false-positive and false-negative results.