Multimodality Imaging of Benign and Malignant Diseases of the Nipple-Areolar Complex.

The nipple-areolar complex (NAC), a unique anatomic structure of the breast, encompasses the terminal intramammary ducts and skin appendages. Several benign and malignant diseases can arise within the NAC. As several conditions have overlapping symptoms and imaging findings, understanding the distinctive nipple anatomy, as well as the clinical and imaging features of each NAC disease process, is essential. A multimodality imaging approach is optimal in the presence or absence of clinical symptoms. The authors review the ductal anatomy and anomalies, including congenital abnormalities and nipple retraction. They then discuss the causes of nipple discharge and highlight best practices for the imaging workup of pathologic nipple discharge, a common condition that can pose a diagnostic challenge and may be the presenting symptom of breast cancer. The imaging modalities used to evaluate and differentiate benign conditions (eg, dermatologic conditions, epidermal inclusion cyst, mammary ductal ectasia, periductal mastitis, and nonpuerperal abscess), benign tumors (eg, papilloma, nipple adenoma, and syringomatous tumor of the nipple), and malignant conditions (eg, breast cancer and Paget disease of the breast) are reviewed. Breast MRI is the current preferred imaging modality used to evaluate for NAC involvement by breast cancer and select suitable candidates for nipple-sparing mastectomy. Different biopsy techniques (US -guided biopsy and stereotactic biopsy) for sampling NAC masses and calcifications are described. This multimodality imaging approach ensures an accurate diagnosis, enabling optimal clinical management and patient outcomes. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Breast Angiosarcoma: Imaging Features With Histopathologic Correlation.

Breast angiosarcoma is a rare malignancy of endothelial origin that can be categorized as primary angiosarcoma (PAS) or secondary angiosarcoma (SAS) based on etiology. Primary angiosarcoma typically affects younger women with no known risk factors, whereas SAS of the breast typically develops in older women who have undergone breast cancer treatment. There are two types of SAS, one that develops in the setting of chronic lymphedema and one that develops as a radiation-associated neoplasm after breast-conserving therapy (BCT). Clinically, PAS often presents as a palpable mass that may be rapidly growing, whereas SAS presents with skin changes such as erythematous plaques or nodules or with areas of skin discoloration. Mammographically, the appearance of PAS can be nonspecific and may be obscured by the dense tissue that is characteristic of the young patient population it typically affects. Cases of mammographically occult PAS have been visible at US and MRI. Mammography and US have been found to be less sensitive than MRI for the diagnosis of secondary radiation-associated angiosarcoma. Angiosarcomas, both PAS and SAS, are graded, depending on degree of differentiation, as low, intermediate, or high grade. Endothelial markers such as ERG and CD31 immunohistochemical stains are used to support the diagnosis of angiosarcomas. In this article, we review the clinical presentation, imaging findings, associated histopathology, and treatment of primary and secondary breast angiosarcoma.