不明病因的腱鞘囊腫通常附著於關節囊或肌腱鞘膜。腱鞘囊腫可能會發生在任何關節。它有許多不同的表徵，乃是手部、腕部和腳部最常見的軟組織腫瘤。然而它卻很少發生在髖關節。我們提出一個臀部髖關節腱鞘囊腫的病例。經過36個月的追蹤，患者並無不適感，而且囊腫沒有復發。此外，對於一個不明本質的深層腫瘤，我們建議，有時候手術探查術是必要的。

Ganglia are cystic lesions of uncertain etiology that are usually attached to the joint capsule or tendon sheath. They have many different appearances and are the most common soft tissue tumors of the hand, wrist, and foot. A ganglion cyst of the hip occurs rarely and we present such a case. Neither further complaints nor recurrence were observed during a follow-up period of 36 months. We suggest that surgical exploration is needed if the nature of a deep-seated mass is unclear.