Correlation between ultrasound characteristics, mammographic findings and histological grade in patients with invasive ductal carcinoma of the breast

AIM: To investigate the relationship between ultrasound characteristics. ma mmographic findings and histological grade in cases of invasive ductal carc inoma which produce a mass on ultrasound. MATERIAL AND METHODS: A retrospective review was performed of the imaging f indings in 120 patients diagnosed with invasive ductal carcinoma of the bre ast between January 1996 and December 1997. Imaging findings were correlate d with the histological grade of tumour. RESULTS: High-grade tumours were significantly larger both on ultrasound an d mammography (P < 0.016). A spiculated margin on mammogram was documented in 72% of low-grade tumours compared with only 24% of high-grade tumours (P = 0.001), Twenty-two per cent of low-grade tumours had a poorly defined ma rgin on mammography compared with 66% of high-grade tumours (P = 0.001). At ultrasound, 16% of high-grade tumours (95% confidence limits 7-29%) had a well-defined margin. Acoustic enhancement was seen in 36% of high-grade tum ours compared with only 9% of low and intermediate-grade tumours (P = 0.003 ): 22% of all tumours showed acoustic enhancement. Acoustic shadowing was s een in 71% of low-grade tumours compared with only 28% of high-grade tumour s (P = 0,003), Malignant-type microcalcification was seen on mammogram in 6 % of low-grade tumours compared with 31% of high-grade tumours (P = 0,045). CONCLUSION: The classical appearance of a malignant breast mass as a spicul ated mass on mammogram associated with acoustic shadowing on ultrasound is more typical of a low-grade tumour, In comparison, high-grade tumours are m ore likely to demonstrate posterior acoustic enhancement, and a proportion has a well-defined margin on ultrasound. Therefore, high-grade invasive duc tal carcinoma may paradoxically display similar imaging features to a benig n breast mass. (C) 2000 The Royal College of Radiologists.