Each study site is projected to collect approximately 75 cyst cases and 75 solid cases for a total of 150 cases, stratified across the four (4) recognized breast tissue density categories with at least 50% of cases from subjects with heterogeneous and extremely dense breast compositions. The composition of the cyst cases at each site is projected to consist of 25 simple cysts and 50 complicated and complex cysts for a total of 75 cyst cases. All enrolled subjects will undergo ultrasound guided aspiration or biopsy or surgical excision, as applicable for the index lesion. Cytologic or histologic results for all lesions will be performed and collected.