Hip Ganglion Cyst Causing Femoral Nerve Dysesthesia
Subsequent electrodiagnostic studies revealed normal responses of the left femoral and saphenous nerves. Magnetic resonance imaging demonstrated a multilobulated hyperintense T2 cystic lesion over the anteromedial aspect of left acetabulum with mild mass effect in between the left femoral vessels and left femoral nerve (Fig. 2). Although the patient refused aspiration or resection of the ganglion cyst, at 3-month follow-up, she reported slight improvement of numbness without any neurologic deficit after conservative treatment.
Ganglion cysts are benign fluid-filled lesions that usually develop from mucoid degeneration of joint capsule, tendon, or tendon sheaths.1 Sonography is considered the imaging modality of choice because it is accurate for distinguishing between solid and cystic inguinal mass lesions.2 A peripheral neuropathy is an uncommon presentation of hip ganglion, and rarely is a nerve compression readily identified.3 Although electrodiagnostic studies are the criterion standard for peripheral neuropathy, normal electrodiagnostic studies may not exclude a mild or intermittent lesion, as seen in this patient. In addition, electrodiagnostic studies often have limitations and difficulties in precise lesion localization.4 Therefore, it is important for a physician to recognize the nearby ganglion cyst as the cause of dysesthesia and prevent further invasive management.3 Whereas magnetic resonance imaging illustrates superior anatomic relationship between a mass lesion and nearby neurovascular structures, in-office ultrasonography is a more accessible and cost-effective first-line tool to diagnose ganglion cysts.