9/17/2023 0 Comments No monoclonal protein detectedIn a Mayo Clinic series of 1596 patients with AL amyloidosis, only 6 (0.4%) showed delayed progression (at 10 to 81 months) to overt myeloma ( 7). In the 10% of cases when myeloma and amyloid overlap, patients almost always present with signs of myeloma first. While both multiple myeloma and AL amyloid are clonal plasma cell disorders, amyloidogenic light chains do not typically cause lytic bone lesions or hypercalcemia, findings associated with multiple myeloma. Although most patients have evidence of multisystem deposition, they typically present with complaints related to involvement of a particular organ system. Up to 20% of individuals ≥50 years with nephrotic-range proteinuria (>3.5 g/day) have AL amyloidosis ( 6). Clinical signs of renal amyloidosis may include albuminuria, hypoalbuminemia, and Bence Jones proteinuria. While glomerular deposition is most common, fibrils may also accumulate in Bowman's capsule, renal tubules, and various renal vessels. Copyright © American Society of Hematology.Īs with our patient, at least 75% of patients with AL amyloid have clinical evidence of renal deposition. Reprinted with permission from Merlini and Stone, Blood 2006 ( 3). ( b) Periorbital purpura exacerbated by the Valsalva maneuver is seen in 6% of patients. ( a) A patient with macroglossia and purpura, Macroglossia is observed in 12% of patients with AL. Prototypical physical findings in primary systemic (AL) amyloidosis. Periorbital vascular infiltration can manifest as purpura, which may result after Valsalva, a classic finding in amyloidosis (Figure (Figure4 4) ( 3). Infiltration of the tongue musculature may generate macroglossia. Accumulation of fibrils in the liver can cause hepatomegaly and liver dysfunction ( 5). Peripheral nerve amyloidosis may generate a variety of neuropathies. Gastrointestinal deposition can induce diarrhea, bleeding, protein loss, and/or malabsorption. Cardiac infiltration can cause arrhythmias and/or restrictive cardiomyopathy. The location of the deposits determines the clinical manifestations. Tissue deposits from AL amyloidosis can occur in many organs, including the kidney, liver, heart, spleen, tongue, skin, ligaments, peripheral nerves, adrenal glands, bladder, small bowel, and bone marrow. AL amyloidosis is rare, with an incidence of 4.5 per 100,000, approximately one tenth the incidence of multiple myeloma ( 3). In the remaining cases, these protein deposits are products of kappa-restricted plasma cell clones. In 75% of cases, the fibrillar deposits of AL amyloidosis are composed of monoclonal lambda light chain proteins or fragments from their variable regions ( 3, 4). Our patient had primary systemic (AL) amyloidosis, which occurs when a monoclonal population of plasma cells generates excess amyloidogenic immunoglobulin light chains. At least 24 different lower-molecular-weight proteins are capable of forming these fibrillar deposits which, when extensive, can interfere with normal physiological function ( 2). Subsequent renal biopsy also showed lambda light chain amyloid.Īmyloidosis describes the extracellular deposition of insoluble fibrils in the walls of small blood vessels and various organs. Bone marrow aspirate (Figure (Figure3 3) and biopsy revealed plasmacytosis of 10% to 15% and light chain amyloid, with a kappa:lambda ratio of 1:50. While serum immunofixation electrophoresis (IFE) was negative for monoclonal light chain (“Bence Jones”) protein, urine IFE did detect a monoclonal lambda protein (Figure (Figure2 2). Quantitative immunoglobulins were depressed, with IgG of 385 mg/dL, IgA of 72 mg/dL, and IgM of 140 mg/dL. Despite significant albuminuria, her serum albumin was 3.9 g/dL. Initial 24-hour urine specimen collected 5.1 g of protein, 64.4% of which was albumin by urine protein electrophoresis (Figure (Figure1 1). This was confirmed by a radionuclide liver-spleen scan, which showed decreased splenic uptake ( 1). Howell-Jolly bodies were identified on peripheral blood smear, suggesting hyposplenism. At that time, the patient's spleen and liver were enlarged. Two years later, a paratracheal node was noted during screening chest x-ray. For unclear reasons, no further evaluation or treatment was undertaken then. While the breast biopsy was benign, pathology from the lymph node revealed amyloid. In 1977, an asymptomatic 68-year-old woman underwent biopsy of a supraclavicular node that had been detected at the time she presented for breast biopsy.
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