An intraneural ganglion cyst of the ulnar nerve at the wrist: a case report and literature review

Abstract

Background Intraneural ganglion cysts of the ulnar nerve at the wrist are rare and poorly understood. We report a case of an intraneural ganglion cyst at the level of the wrist. Case presentation: A 48-year-old man presented with the complaints of weakness for 6 months and serious aggravation for 1 month in his right hand. After examinations, including ultrasound, the patient was diagnosed with an intraneural ganglion cyst. Intraoperatively, with exposure of the ulnar nerve, we found that the intraneural ganglion cyst was at the level of Guyon’s canal and extended approximately 6 cm proximally. Postoperatively, sensation of the fingers was normal, but atrophy of his muscles and limited straightening of his ring and little fingers were similar to those preoperatively. Conclusions Diagnosis of an intraneural cyst before surgery is mostly based on ultrasound and magnetic resonance imaging. Transection of the articular branch is an important measure to prevent recurrence of this cyst. If the ulnar nerve is compressed and causes symptoms, nerve decompression, including removal/aspiration of the cyst, and sometimes external neurolysis of the nerve, are necessary to relieve the symptoms and allow regeneration of the nerve. However, these should be performed without damaging the nerve fascicles.

Multimodality imaging review of ulnar nerve pathologies

“…They may also originate from tendon sheaths and rarely arise from a nerve sheath. 50 The etiology is unknown, but thought to be related to degeneration of soft tissue structures surrounding a joint. They are most commonly seen in the volar side of the wrist.…”

“…49 Impingement of the ulnar nerve in Guyon's canal is rare; however, several cases of intraneural and extraneural ganglion cysts have been implicated. [50][51][52][53] Multiple cases of ganglion cysts at the elbow causing ulnar neuropathy at the cubital tunnel have also been reported. [54][55][56][57] On ultrasound, simple ganglion cysts appear as anechoic areas with a thin wall, no Doppler flow, and variable acoustic enhancement.…”

“…[54][55][56][57] On ultrasound, simple ganglion cysts appear as anechoic areas with a thin wall, no Doppler flow, and variable acoustic enhancement. 50,58,59 Complex cysts may include features such as internal septations, thick cyst wall, color Doppler flow, and a partial solid component. 58 On MRI, uncomplicated cysts are observed to be typically T1 hypointense and T2 homogeneously hyperintense rounded or lobular masses with a thin rim (Figure 7).…”

Review Article “Spotlight on Ultrasonography in the Diagnosis of Peripheral Nerve Disease: The Evidence to Date”

“… 65 , 66 Importantly, the majority of these electrodiagnostically “non-localising” ulnar neuropathies can be localised with ultrasound. 65 , 66 In addition, ultrasound can readily diagnose ulnar nerve injury at Guyon’s canal for example due to cycling-related wrist compression, 67 intraneural ganglion cyst 68 or ulnar artery thrombosis. 69…”

Intraneural ganglion cyst of the ulnar nerve causing cubital tunnel syndrome masquerading a peripheral nerve abscess of a neuritic leprosy

“…They are associated with painless swelling in the nerve. 3 Pure neuritic leprosy manifests with neurological symptoms without any skin manifestations. Nerve abscess due to pure neuritic leprosy producing nerve abscess is reported.…”