Amyloidosis of the Femoral Neck: An Unusual Cause of Pathologic Fracture.

The deposition of amyloid within human tissue can be detrimental to the proper functioning of multiple organ systems. While the infiltration of the amyloid protein within the musculoskeletal soft tissues can lead to compressive neuropathies, tendon irritation or rupture, and joint stiffness, pathologic fracture as a result of amyloid deposition in bone is a rare manifestation of amyloidosis. We present a case of pathologic fracture of the femoral neck from amyloid deposition in a 59-year-old male on chronic hemodialysis who was found to have lytic lesions in his proximal femur. At the time of hemiarthroplasty, histopathologic analysis of a femoral head sample revealed apple-green birefringence of the deposits under polarized light, consistent with amyloid deposition. Clinicians should have a high index of suspicion for the atypical presentation of amyloidosis in a patient on chronic hemodialysis with lytic bone lesions.