Atypical bisphosphonate-associated subtrochanteric and femoral shaft stress fractures: diagnostic features on bone scan.

A 69-year-old woman presented with a spontaneous right subtrochanteric hip fracture. Pan-imaging following orthopedic repair failed to identify a primary malignancy to explain the presumed pathologic basis for this fracture. The patient then underwent bone scintigraphy and SPECT/CT which showed mild uptake in multifocal endosteal thickening of the lateral left femoral diaphysis, diagnostic of bisphosphonate-associated femoral shaft stress fractures, but no evidence of metastatic bone disease. Atypical bisphosphonate-associated subtrochanteric and femoral shaft stress fractures have a fairly specific appearance on bone scintigraphy, and nuclear medicine physicians should be aware of this relatively infrequent emerging pathology.