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A 76-year-old woman was found to have abnormally enlarged and calcified bilateral axillary lymph nodes on a screening mammogram (Figure 1). These correlated with morphologically abnormal lymph nodes on US with associated internal echogenic reflectors suggestive of calcifications (Figure 2). The patient had a known diagnosis of multiple myeloma with associated biopsy-proven systemic light-chain (AL) amyloidosis involving multiple lymph node stations, including mediastinal nodes seen on CT of the chest (Figure 3). These abnormal morphology lymph nodes were also hypermetabolic active on FDG-PET-CT (Figure 4). Thus, the axillary lymph nodes on mammogram and US were considered to be the sequelae of amyloidosis.
Amyloidosis is a rare disorder characterized by abnormal plasma cell production and extracellular deposition of insoluble abnormally folded proteins in a beta-pleated sheet format. Systemic AL amyloidosis is known to occur in 10% to 15% of patients with multiple myeloma, and it is a known complication of multiple myeloma. Amyloidosis of the breast has been previously described as either localized or systemic, often presenting clinically as a painless solitary breast mass that may be associated with calcifications. Changes in breast texture and appearance have been clinically reported. The initial presentation of amyloid in breast imaging as isolated bilateral enlarged calcified lymph nodes is a rare presentation that breast radiologists should be aware of. This case is an example of systemic AL amyloidosis, which manifested as widespread hypermetabolic calcified lymphadenopathy involving multiple lymph node stations, including the axilla. Unless a diagnosis has already been established, a lymph node biopsy is essential to establish a histological diagnosis and guide treatment for abnormal calcified axillary lymph nodes because various benign and malignant entities may present with this imaging appearance. Coarse axillary calcifications may be seen in granulomatous disease, sarcoid, or parasitic infections. Metastatic disease from breast primary, gastric, or papillary thyroid cancer can also present with calcifications ranging from fine pleomorphic to coarse. The clinical significance of systemic amyloid is end-organ damage due to abnormal extracellular protein deposition in organs such as the heart and kidneys. The patient presented here subsequently developed worsening dyspnea on exertion with elevated B-type natriuretic peptide levels. This led to an endomyocardial biopsy showing periarteriolar amyloid deposition, for which treatment with daratumumab was started.