Complex cystic breast masses in ultrasound examination.

Complex cystic masses are defined as lesions composed of anechoic (cystic) and echogenic (solid) components, unlike complicated cysts, the echogenic fluid content of which imitates a solid lesion. Complex masses are classified as ACR4 and require histological verification by percutaneous biopsy and/or surgical ablation. The etiology is diverse, and can be benign or high risk (an abscess, hematoma, fat necrosis, fibrocystic mastopathy, a phyllodes tumor, papilloma) as much as malignant (papillary cancer, necrotic cancer, a ductal carcinoma in situ, metastases). The biopsy technique must be adapted to each case and it is often necessary to insert a coil during the procedure. Histopathological correlation is essential to ensure that the samples are representative and concur with the ultrasound appearance, so as not to fail to recognize high risk or malignant lesions requiring appropriate management.