Bone scan findings in idiopathic hyperphosphatasia.

Hyperphosphatasia is a rare genetic disorder characterized by failure to transform woven bone into lamellar bone. A 12-year-old girl with the complaint of right humeral pain was referred for a bone scan with a suspicion of a right humeral bone cyst with respect to the radiographic examination. Bone scan revealed increased uptake in the right humerus at the site of the radiographic abnormality. Increased radiotracer uptake was observed not only in the right humerus, but also at other sites including the pelvis, femurs, and tibias. The patient had a traumatic femoral fracture in the right femur 3 years earlier. For the diagnosis of hyperphosphatasia, clinical, chemical, and radiographic findings are essential, and histopathologic diagnosis should also be done. Nowadays, mutations on the gene causing hyperphosphatasia have been described. In this case, we have used only clinical, chemical, and radiographic findings for diagnosis and, unfortunately, we did not perform a bone biopsy.