In a patient with amyloidosis involving the heart, kidneys, and skeletal muscles, a Tc 99m pyrophosphate "bone" scan demonstrated intense uptake of tracer by the skeletal muscles; but not by the heart or kidneys. Using the alizarin red stain, prominent calcium deposits were detected histologically in association with the skeletal muscle amyloid. These findings suggest that certain amyloid deposits will take up Tc 99m pyrophosphate, but only if sufficient amounts of calcium are associated with the amyloid.
Keg words: arnyloidosis, radionuclide imaging
INTRODUCTIONAmyloidosis, the deposition within various organs of a distinctive fibrillar protein, is associated with a number of disease processes. When amyloidosis is associated with a plasma cell dyscrasia, monoclonal immunoglobulin light chains become deposited in the form of amyloid within various organs [I]. The heart, alimentary tract, kidneys, and liver are frequently affected and death usually occurs from cardiac involvement [2]. Patients with this syndrome have increased numbers of plasma cells in the bone marrow, and monoclonal light chains are demonstrable in the serum or urine [3,4]. When amyloid involves the thyroid, liver, or spleen, appropriate radionuclide scans may demonstrate organomegaly or decreased tracer uptake (51. A number of brief reports have described the uptake of various bone seeking tracers by amyloid deposits in the heart [6-81, skeletal muscles [8,9], skin [lo], liver [I I], and periarticular tissues [12]. It has been suggested that this phenomenon is due to amyloid calcification, and in two reports [7,8] calcium was demonstrated in amyloid by light microscopy [7,8] or electron microscopy [8]. However, it was not confirmed that those amyloid deposits not taking up tracer were also noncalcified.In this communication, we report a case of amyloidosis associated with a plasma cell dyscrasia in which there was histologically proven involvement of heart, kidneys,
CASE REPORTA 69-year-old man was admitted to the hospital with congestive cardiac failure.There was no macroglossia, hepatosplenomegaly, purpura, or orthostatic hypotension.The hemoglobin was 11.4 gm%, WBC 6300/mm3, and the platelet count 244,000/mm3. Serum creatinine was 1.6 mg% (normal 0.8-1.2), BUN 272 mg% (normal 8-20), and creatinine clearance 35 ml/min. Serum electrophoresis was normal, but immunoelectrophoresis showed an M band of lambda chains. The Ig G was 563 mg% (normal 560-1512), IgA 60 mg% (normal 104-448), and IgM was 33 mg% (normal 66-352). The patient was excreting in his urine 1000 mg/24 hr. of lambda light chains. There were 23.8% plasma cells in the bone marrow and many appeared atypical. The serum creatinine phosphokinase activity was 309 IU per litre (normal 36-188), and was predominantly the MM isoenzyme. The prothrombin time and partial thromboplastin time were normal. Coagulation factor IX was 93%, and factor X was 64% (normal ranges 50-150%).The chest x-ray demonstrated cardiomegaly and congestive cardiac failure. The electrocardiogram revealed varying atri...
