Juxtaacetabular ganglion as a differential diagnosis in pulsating groin masses.

Ganglion cysts of the hip joint are uncommon synovial-lined fluid-filled juxtaarticular groin lesions. Whereas in the past the correct diagnosis was often made only at surgery there are now valuable imaging methods used for the diagnostic work-up. In experienced hands ultrasonography (US) combined with colour duplex Doppler ultrasonography (CDDS) as a real-time imaging technique easily performed at the patient's bedside is a valid alternative to more expensive or invasive investigations. We report on a patient who presented with a ganglion cyst and in whom first supported by conventional US an aneurysm of the femoral artery was suspected. The diagnosis of a juxtaarticular ganglion was subsequently correctly made at our institution by CDDS and magnetic resonance imaging, respectively, and the cyst was exstirpated successfully. The differential diagnosis of a pulsating groin mass as well as the most useful and specific imaging methods in the diagnostic work-up in this clinical setting are discussed.