Giant Synovial Cysts of the Hip Joint: An Important but Rare Differential Diagnosis of an Inguinal Swelling

Abstract

Synovial cysts around the hip joint are commonly mistaken for other more common causes of an inguinal swelling. We present a report on two patients in whom abnormal pulsatile masses in the groin caused diagnostic difficulty. Patients were initially admitted under vascular surgeons with a clinical diagnosis of aneurysm. Ultrasound examination was useful in excluding aneurysm. Detailed clinical examination revealed painful restricted hip movements and a radiograph showed evidence of arthritis in the hip joint. CT scan confirmed it to be a synovial cyst. Computed arthrotomogram or arthrography showed communication of the cyst with the hip joint. Synovial cysts and iliopsoas bursa enlargement may be more common than previously reported and should be considered as a differential diagnosis in patients with unusual inguinal swelling.