Imaging Features of Amyloid of the Breast: Review of 94 Cases From the Literature and 6 New Cases

Breast amyloidosis is a rare disease that can be secondary to systemic disease or localized to the breast. The imaging findings are variable with features suspicious for breast malignancy such as calcifications, focal asymmetry, and mass that prompt the recommendation for biopsy. US correlates are also variable, though when present, most are irregular hypoechoic masses. The imaging features overlap with those of primary breast malignancy. Therefore, biopsy and histopathologic correlation are needed to confirm a concordant diagnosis and for amyloid typing. Because approximately half of cases are associated with B-cell disorders, referral to hematology-oncology for evaluation is important. An additional 16% of patients have systemic autoimmune inflammatory disease such as Sjogren's syndrome, rheumatoid arthritis, systemic lupus erythematosus, and polymyalgia rheumatica. Very rare cases are associated with iatrogenic amyloid formation because of injection of synthetic insulin. The remaining approximate one-third of cases are localized to the breast and other limited sites. These cases most commonly occur in postmenopausal women and are often detected on screening mammography. After evaluation to exclude systemic disease, these patients do not require surgical excision or medical treatment.