A case of probable hydroxyapatite deposition disease (HADD) of the hip.

We describe a patient with acute calcific periarthritis in an unusual site, the ilio-femoral ligament. The clinical findings in this patient resembled those of septic arthritis. T2*-weighted images with gradient field echo clearly showed foci of low signal intensity in this region, corresponding to the calcification shown on plain radiographs, and increased signal intensity around the foci, representing edema. These signal intensities were diagnostic of the disease.