PURPOSE: The aim of this study was to evaluate the role of ultrasound (US)-guided core biopsy in the diagnosis of ductal carcinoma in situ (DCIS) and to correlate the histological results on percutaneous biopsy and surgical excision.
MATERIALS AND METHODS: Out of 2,423 consecutive core biopsies performed under US guidance, we evaluated 65 lesions with a histological diagnosis of DCIS. All patients underwent mammography, high-frequency broadband US and percutaneous breast biopsy with a 14-gauge needle and a mean number of five samples (range 4-7 passes). Surgical excision was performed in all cases, and the histological results on the surgical specimen were correlated with those on core biopsy samples. The sonographic features of DCIS lesions were described, comparing pure DCIS (those confirmed by definitive histology) and DCIS with invasive component at surgical excision.
RESULTS: Twenty-seven out of 65 DCIS at core biopsy were found to have an invasive or microinvasive component at surgical excision, leading to rate of histological underestimation of core biopsy of 41.5%. The most frequent sonographic appearances were: (a) mass without microcalcifications (47.4% of pure DCIS, 63% of DCIS with invasive component); (b) mass with microcalcifications (23.7% of pure DCIS, 22% of DCIS with invasive component); (c) isolated microcalcifications (10.5% of pure DCIS); (d) ductal abnormalities (18.4% of pure DCIS, 15% of DCIS with invasive component).
CONCLUSIONS: Due to the high underestimation rate of core biopsy, caution is mandatory in the case of DCIS diagnosis on core biopsy. Although some histological features (such as stromal fibrosis, periductal inflammatory infiltrate, high nuclear grade) can suggest the presence of an invasive component, the sonographic appearance of DCIS cannot be used to predict the cases that are underestimated on US-guided core biopsy. Nevertheless, a sonographically detectable solid component, either inside dilatated ducts or associated with microcalcifications, and a size greater than 20 mm are frequently associated with the presence of an invasive component.
