Ann Rehabil Med.  2014 Jun;38(3):427-432. 10.5535/arm.2014.38.3.427.

Acetabular Paralabral Cyst as a Rare Cause of Obturator Neuropathy: A Case Report

• Kim SH
• Seok H
• Lee SY
• Park SW

• KMID: 2165765
• DOI: http://doi.org/10.5535/arm.2014.38.3.427

Abstract

An acetabular paralabral cyst is a benign soft tissue cyst usually seen in association with a tear of the acetabular labrum. Acetabular paralabral cysts are often the cause of joint pain, but they rarely cause compression of the adjacent neurovascular structures. We present a case of a 63-year-old male patient who had paresis and atrophy of right hip adductor muscles. Right obturator neuropathy was confirmed through an electrodiagnostic study. In addition, magnetic resonance imaging showed a paralabral cyst in the right acetabulum which extended to the pelvic wall. The patient underwent conservative treatment without surgical procedure. The pain was decreased after 1 month of conservative therapy. The pain was decreased at the 1-month follow-up. Follow-up electromyography showed polyphasic motor unit potentials in adductor magnus and adductor longus muscles. Based on the experience of this case, an acetabular paralabral cyst should be considered as one of the rare causes of obturator neuropathy.

Keyword

Acetabulum; Synovial cyst; Obturator nerve

MeSH Terms

Acetabulum*
Arthralgia
Atrophy
Electromyography
Follow-Up Studies
Hip
Humans
Magnetic Resonance Imaging
Male
Middle Aged
Muscles
Obturator Nerve
Paresis
Synovial Cyst

Figure

• 

  Fig. 1 T2-weighted magnetic resonance images of the pelvis. Axial image (A, B), coronal image (C), and parasagittal image (D) show an approximately 2.8 cm sized well-defined, lobulated, contoured, high signal intensity cystic lesion (arrow) in the anteroinferior aspect of the right acetabulum. This cystic lesion extended to the right obturator muscle and the lateral wall of lesser pelvis. (D) Parasagittal T2-weighted image demonstrates that the lobulated cystic lesion (arrow) extended along the course of the obturator nerve (arrowheads).

• 

  Fig. 2 Magnetic resonance imaging findings of the obturator muscle. Axial T1-weighted image (A), axial T2-weighted image (B), and gadolinium-enhanced coronal T1-weighted image (C) show high signal intensity in the right obturator muscle (arrow). These findings are suggestive of fatty atrophy.

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