Ultrasonic elasticity imaging is a promising new tool for breast cancer diagnosis and management. Ultrasound is applied to sense small local tissue deformations noninvasively to image stiffness and thus exploit the large intrinsic stiffness contrast generated during the progression of many diseases in vivo. This paper briefly reviews several related approaches to breast elasticity imaging to explain some of the observed variability in breast imaging results. Preliminary clinical results from a population of 13 patients with small and nonpalpable breast lesions obtained with a low noise elasticity imaging algorithm developed in our group are then reported. All the benign lesions exhibited normal elasticity ranges. About half of the malignant lesions were undetected with elasticity imaging most likely because of their small size ( < 7mm) or softening from the addition of fatty-replaced tissue. Other malignant lesions were clearly identified as areas with extreme elasticity values compared to their surroundings. We observed that some malignant lesions did not exhibit any desmoplasic stiffening while others showed an uncommon softening. It is clear that by broadening the study population to include small and nonpalpable lesions, we see much variability in elasticity image findings.