Intraneural ganglion cysts originating from the hip joint: A single-center experience

Introduction/Aims: Intraneural ganglion cysts (INGCs) are non-neoplastic mucinous cysts within the epineurium of peripheral nerves. Characteristics of INGCs around the hip joint have not been adequately described. We aimed to describe clinical features, imaging findings, and treatment outcomes in patients with INGCs originating from the hip joint. Methods: We retrospectively included cystic lesions around the hip joint satisfying the following inclusion criteria over 6 years: (1) multilocular elongated hyperintense cystic mass on T2-weighted imaging; and (2) distribution along the course of the peripheral nerve and its branches on magnetic resonance imaging (MRI). Results: Six patients with an INGC around the hip joint were identified. Parent peripheral nerves were the sciatic nerve (four patients), the superior gluteal nerve (one patient), and the nerve to quadratus femoris (one patient). Buttock, groin, or lower extremity pain/paresthesias were the initial symptoms in all patients. INGCs within the articular branches of the hip joint were identified on MRI. Four patients underwent arthroscopic debridement and capsulotomy. All patients showed generally favorable outcome regardless of treatment. Discussion: Physicians should consider the possibility of INGCs originating from the hip joint as a cause of nontraumatic hip, buttock, or lower extremity pain. This can occur in any nerve innervating the hip joint, and usually it originates in the posterior capsule of the hip joint. Arthroscopic surgery shows promising results; however, more information about the surgical technique and long-term follow-up results are needed.