E1649. A Guest in the Breast: An Imaging Review of Breast Amyloidosis
  1. Regan Ferraro; UCLA Medical Center
  2. Bo Li; UCLA Medical Center
  3. Tiffany Chan; UCLA Medical Center
Amyloidosis is a disease characterized by the abnormal deposition of extracellular fibrillar proteins. This entity can be either systemic or localized, with involvement of almost any organ. Amyloidosis of the breast is a rare entity and can mimic both benign and malignant pathologies on imaging, and biopsy is required to exclude primary breast malignancy. Amyloidosis should be on the differential for any breast mass in a patient with suspicious findings and a concomitant hematologic or systemic disease or systemic amyloidosis. Radiologists should be aware of this entity and its many imaging manifestations in order to communicate this differential diagnosis to pathologists, as Congo red histopathological staining is needed to confirm the diagnosis.

Educational Goals / Teaching Points
This exhibit focuses on the manifestations of amyloid primarily in the breast as well as other commonly involved organs. This will include a review of the incidence, common presentations of amyloid and various imaging appearances of amyloid in the breast and other commonly involved organs, as well as key pathologic features that aid in the diagnosis. Additionally, the radiologist should know when to include amyloidosis on the differential for an abnormal breast finding.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
The exhibit will discuss the pathophysiology of amyloidosis and its relationship to hematologic disorders. The incidence and prevalence of localized and systemic disease will be reviewed. Next, we will discuss the most common clinical presentations and imaging findings of amyloid on mammography and ultrasound. Sample cases will be presented to highlight key imaging features. Given its suspicious imaging findings, tissue diagnosis is essential to exclude a primary breast malignancy and avoid unnecessary surgery. Histopathologic correlation will be reviewed. Lastly, while amyloidosis of the breast typically has a benign course, the diagnosis of amyloidosis in the breast carries significant implications for patient management. As such, patients should undergo full evaluation for concomitant hematologic disorders, malignancies, and systemic amyloidosis.

It is important that every radiologist is familiar with the range of appearances of breast amyloidosis on mammography, ultrasound, and histopathology. Overlapping imaging features with primary breast malignancy can make diagnosis a challenge, and radiologists need to maintain a high level of suspicion to include amyloid on the differential when applicable, as there are significant implications for patient management based on accurate diagnosis.