In this examination, the doctor assesses the construction of the breast: the proportion of adipose tissue to the glandular and connective tissue contents. The doctor also assesses regional lymph nodes and, what is the most important, looks for focal lesions and breast tumours. Some of them are mild and do not require treatment (e.g., simple cysts), others are usually an indication for breast biopsy. Breast ultrasound examination helps to assess the size, structure and blood supply of the tumour. Such features allow us to assess the risk of malignant tumour. Visualization of a small tumour by ultrasonography allows for precise removal of tissue for histopathological examination by fine needle aspiration and core needle biopsy. In addition to mammography, breast ultrasound is the most important test in the early detection of breast cancer, especially in women before the age of 40.