Amyloid Deposition of the Breast

Abstract

76 -year-old woman with a 15-year history of indolent multiple myeloma presented for annual screening mammography. Her myeloma had been diagnosed 15 years earlier by bone marrow biopsy and serum protein immunoelectrophoresis but was not treated because she remained asymptomatic. Annual screening mammography showed grouped, generally smooth branching rodlike calcifications in the upper outer quadrant of the right breast. These calcifications were new since the prior examination a year earlier (Figs. 1A and 1B). No correlative palpable abnormality was present on physical examination. Because of the short-interval appearance of calcium and the branched morphology, biopsy was recommended to exclude breast malignancy. The patient underwent needle localization and surgical excision. Histology showed diffuse dense hyalinized material associated with fibrosis, chronic inflammation (including foreign body‐like reaction), and microcalcifications. This was present in and around ducts, vessels, and stroma. The material exhibited exhibited apple-green birefringence with Congo red stain under polarized light, characteristic of amyloid deposition. No malignancy was identified at pathology (Fig. 1C). Amyloid deposition in the visceral organs may be seen in patients with primary amyloidosis (no preexisting or coexisting disease), multiple myeloma, chronic infectious disease, and chronic inflammatory disease (such as rheumatoid arthritis.) Amyloid tumor of the breast is rare and may present as a similar clinical appearance to mammary carcinoma, with a palpable breast mass and mammogram showing a mass or focal or diffuse density with or without calcifications [1‐6]. Although there are sporadic case reports in the literature, amyloid deposition in the breast has been previously reported only once in the radiology literature to our knowledge [1]. Although it has been incidentally observed as breast nodules or infiltration at autopsy with negative mammograms [2], we are unaware of amyloid presenting as a nonpalpable mammographic abnormality consisting of only indeterminate calcifications on annual screening mammography. The mammographic appearance of nonpalpable amyloid has not been described and is not commonly thought of in the differential diagnosis of nonpalpable breast disease or, more specifically, indeterminate calcifications. In this case, the absence of ill-defined density or a nodule on mammogram may be related to the overall relative increased breast density; however, a discrete lesion was not present on gross pathologic examination either. Amyloid fibrils have an affinity for calcium and deposition around mammary ducts and in blood vessels [3, 6, 7]. In this case, perhaps the branched morphology of the calcium is related to deposition in or around vasculature or mammary ducts. When limited to the breast, primary amyloid tumor is benign. However, secondary amyloidosis may have an ominous significance and poor prognosis [8].