Anterior, posterior, and pinhole views from a bone scan demonstrate a small, cortically based focus of mildly to moderately increased radiotracer accumulation at the proximal left tibia medially (arrow).

Differential Diagnosis

•  Stress fracture: The focal, cortically based uptake in a lower extremity makes this the most likely diagnosis, given the history. The fairly mild uptake suggests this may represent an early stress fracture/reaction.

•  Shin splints: These will also show increased cortically based uptake in the lower extremities but are always located in the mid tibia, and the activity is segmental, running parallel to the bone.

•  Bone metastasis: