E1525. Incidental Extra-Mammary Findings on Breast MRI: Mediastinal Masses and Beyond
  1. Ifeoma Aguanunu; University of Cincinnati
  2. Ann Brown; University of Cincinnati
  3. Charmi Vijapura; University of Cincinnati
  4. Rifat Wahab; University of Cincinnati
  5. Su-Ju Lee; University of Cincinnati
  6. Mary Mahoney; University of Cincinnati
The use of breast MRI to screen and stage breast has dramatically increased over the past few decades, increasing 16-fold in community practice from 2000 to 2011.1 In addition to the breasts tissue, other anatomical structures are commonly included in the field of view, such as the mediastinum, thyroid, lungs, vascular structures, bones, and upper abdominal organs. Although extra-mammary findings (EMFs) are frequently overlooked or inaccurately assessed on breast MRI, several MR sequences provide sufficient detail to allow accurate diagnosis. Radiologists should be aware of the spectrum of EMFs on breast MRI and be able to characterize them as benign, indeterminate, or reasonably suspicious to warrant further work-up.

Educational Goals / Teaching Points
Discuss the frequency of EMFs on breast MRI and commonly reported sites of EMFs; recognize the mediastinal compartments, differential diagnosis for mediastinal masses and their MRI characteristics; review other commonly encountered EMFs; formulate appropriate strategies to guide the work-up and management of EMFs.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Overview of frequency and location of EMFs on breast MRI. Review mediastinal compartments and presentation of specific mediastinal masses and their imaging findings, including the following: teratoma, thymic masses/goiter, lymph nodes in sarcoidosis, esophageal leiomyoma, hiatal hernia, vascular anomalies, vertebral hemangioma, and cervical spinal cord syrinx. Identify other sites of EMFs, including the following: neurofibromatosis type 1, rib fracture, hepatic hemangioma, and pleural effusion. Discuss steps that should be taken when an EMF is identified on breast MRI, including reviewing past imaging studies, assessing patients’ risk factors for having extra-mammary malignant lesions, and formulating recommendations for additional imaging work-up and/or follow-up of EMFs.

As the number of breast MRI studies continues to rise, it is important for radiologists to recognize and report extra-mammary findings because they can be clinically relevant. Benign lesions are the most common extra-mammary findings. However, given the high-risk population undergoing breast MRI, malignant lesions cannot be dismissed, as such findings can significantly alter patient management.