Introduction: Mammography is the only technique of proven efficacy in the early diagnosis of breast cancer, even though its sensitivity is much lower in breasts that are dense or with a high parenchymal-stromal component. In the past malignant breast nodules detected at US in patients with negative mammographic and physical findings were considered incidental findings, but more recent papers report increasing numbers of breast cancers detected only at US.
Purpose: We investigated the yield of US performed as a diagnostic complement in asymptomatic women with mammographic findings that were either negative or poorly readable because of dense breast.
Material and methods: We examined 13 women 37 to 55 years old (mean 47): 9 of them were asymptomatic and 4 had poorly specific physical findings. The patients underwent physical examination, mammography, US, microhistologic biopsy with 14G needles under US guidance and surgery.
Results: Fourteen breast lesions 7.0-15 mm in diameter were detected only by US. Mammography (2 or 3 standard views) was negative in all cases. The lesions detected only by US (10% of all carcinomas) were typified with US-guided needle biopsy and finally confirmed surgically.
Discussion and conclusions: Though obtained in a small series, our results seem to suggest that US should be included in the diagnostic work-up, especially of women with dense breast. Also, any hypoechoic lesion detected at breast US in clinically asymptomatic women with negative mammographic findings should be further investigated with US, needle aspiration or core biopsy to make the final diagnosis.