Rheumatoid synovial cyst of the hip joint: a case report.

Rheumatoid synovial cyst of the hip joint in a 52-year-old man including iliopsoas bursal extension was demonstrated by arthrography and excision biopsy. Surgical excision of the cyst and femoral head replacement were carried out. There was no recurrence for 15 months postoperatively. The condition should be suspected in patients with degenerative changes in the hip joint and adjacent unexplained palpable mass.