Abstract
BACKGROUND Amyloidosis results in fibrillar sheets of beta-pleated amorphous congophilic protein deposition in the extracellular space. Breast amyloidosis is a rare entity, with the first case reported in 1973 and only 2 major case series published since. These deposits can have local or systemic manifestations and typically present unilaterally, although bilateral involvement has been described. Some reported cases of amyloidosis have been linked to breast cancer. CASE REPORT The patient was a 60-year-old woman who presented to the breast surgery clinic for evaluation after image-guided biopsy of a right breast lesion. Core needle biopsy under stereotactic guidance demonstrated pathology consistent with nodular deposition of amyloid, associated with calcifications. Microscopic examination revealed extracellular deposition of acellular eosinophilic material in fat, stoma, and blood vessels. Congo red special stain was positive. Amyloid with Congo red special stain showed apple green birefringence under polarized light. Surgical excision under needle localization was performed, with the final surgical pathology report confirming amyloid deposits. CONCLUSIONS Breast amyloidosis can have calcium affinity, create a foreign body-like reaction with giant cell infiltration, and distribute through periductal, perivascular, or intralobar patterns. Some factors that can contribute to an increased risk or are associated with breast amyloidosis are predisposing clinical conditions, including autoimmune disease, various breast cancers, and B-cell lymphomas. Amyloidosis of the breast should be treated either as primary or secondary, based on etiology. Further studies need to be conducted on whether there are specific genetic markers that predispose populations to the development of amyloidosis of the breast.