Soft tissue uptake of bone seeking radionuclide in amyloidosis

The diagnosis of amyloidosis is often difficult due to variable clinical manifestations and the need for biopsy confirmation. We evaluated the use of bone scanning radionuclides in an effort to delineate soft tissue amyloidosis. Three of 7 patients with proven amyloid reviewed retrospectively, and 3 of 17 studied prospectively had abnormal soft tissue uptake of radionuclide, most commonly diffuse hepatic uptake. Amyloidosis should be considered in any patient with diffuse hepatic uptake or other soft tissue uptake of bone seeking radionuclides. A mechanism for the abnormal uptake (increased calcium content of the involved tissue) is postulated based on in vitro tissue analysis for calcium.