Fibroadenoma of the breast: sonographic appearance.

The sonographic patterns of 100 fibroadenomas, including two giant fibroadenomas and two cystosarcoma phyllodes, were reviewed. The lesions were mostly hypoechoic (92%) and homogeneous in echotexture (72%). Twenty-seven percent of fibroadenomas showed irregular margins. Intratumoral calcifications were noted in 10% of lesions. A marked acoustic shadow without associated calcification was seen in six cases. The mean ratio of the length to the anteroposterior diameter of the tumors was 1.84 +/- 0.52 (standard deviation), indicating an elongation along the general orientation of the breast tissue planes. The ratios of length to anteroposterior diameter calculated in two matching groups of small (less than 1 cm3) fibroadenomas and carcinomas differed significantly. State-of-the-art high-frequency transducers, geometric analysis of tumors, and real-time ultrasound-guided fine-needle aspiration biopsy should help to distinguish between benign and malignant solid breast masses.