E1351. Malignant Mimickers in Mammography
  1. Aisha Sindhu; Atlantic Health
Numerous breast lesions, both benign and malignant, can occur in women of all ages, and it is not uncommon for benign lesions to present with malignant features on imaging. Proper classification of these lesions as benign is crucial to avoid unnecessary workup and undue patient anxiety. Relevant clinical history and mammographic interpretation play a large role in determining the next best step for a patient with a suspicious-appearing breast lesion. When a lesion presents with suspicious characteristics on mammography, it is assigned an appropriate category based on the American College of Radiology (ACR) Breast Imaging Reporting and Data System (BIRADS); typically a 3, 4, or 5. Further workup and management is based on the assigned category. Breast imagers must have a clear understanding of the various presentations of benign breast lesions, and their etiologies, workup, and management.

Educational Goals / Teaching Points
The goal of this exhibit is to review various benign breast lesions that can mimic breast carcinoma on mammography. For each benign entity, we will discuss the basic fundamentals, including etiology, clinical presentation, and demographics. The suspicious imaging findings that would prompt further workup, as well as the proper next step in determining the etiology of a suspicious-appearing lesion, will be detailed. Finally, the post-biopsy management of each entity will be reviewed. Because breast imaging reporting is highly regimented by the BIRADS lexicon and classification, understanding the assigned category of a lesion based on imaging findings, as well as the change in classification following histologic analysis, is imperative. As such, the BIRADS will be discussed, with special note to further recommendations associated with each category.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Benign breast lesions mimicking carcinoma on mammography include fibroadenoma, fat necrosis, phyllodes tumor, papilloma, post-lumpectomy/post-excisional biopsy scar, sclerosing adenosis, fibrous mastopathy, and diabetic mastopathy. The pathophysiologic development of each benign entity will be discussed, including relevant clinical history that may guide the breast imager to conclude a lesion is benign despite non-benign imaging findings. Additionally, the possible mammographic imaging appearances of each entity will be discussed, with emphasis on the suspicious feature or features that may warrant further workup. Finally, post-biopsy management of each entity will be detailed.

Histologically-benign breast lesions may present with suspicious features on mammography. These lesions must be evaluated in the context of the patient’s history, clinical exam, and symptoms. Breast imagers must be aware of the various mammographic presentations of benign breast lesions and recommend additional workup as needed by way of the assigned BIRADS category.