Dialysis-related amyloidosis mimicking metastatic bone disease: a scintigraphic pitfall of non–MDP-avid osteolytic lesions on bone SPECT/CT

BACKGROUND: Dialysis-related amyloidosis (DRA) is a recognized complication of long-term dialysis caused by progressive deposition of β2-microglobulin amyloid in osteoarticular and periarticular tissues. Although its musculoskeletal manifestations are well described, bone lesions from DRA may be misidentified as malignant disease on imaging, posing a diagnostic challenge. CASE PRESENTATION: We describe a 70-year-old woman on long-term dialysis who presented with a pathologic femoral neck fracture and adjacent osteolytic lesions initially suspicious for metastatic disease or brown tumor. Bone SPECT/CT showed uptake only at the fracture site with background activity in the lytic lesions. Histopathological examination confirmed the diagnosis of amyloidosis by Congo red staining. CONCLUSIONS: This case illustrates that DRA may present as non-MDP-avid osteolytic lesions on bone scintigraphy, potentially mimicking malignant bone disease. Awareness of this scintigraphic pitfall is essential when evaluating dialysis patients with atypical skeletal lesions.