Sim Jaehoon, Kwak Hyunseok, Lee Soonchul, Min Kyunghoon
Department of Rehabilitation Medicine, CHA Bundang Medical Center, CHA University School of Medicine, Seongnam, Korea.
Rehabilitation and Regeneration Research Center, School of Medicine, Seongnam, Korea.
Medicine (Baltimore). 2020 Sep 11;99(37):e22123. doi: 10.1097/MD.0000000000022123.
Peroneal neuropathy is the most common type of peripheral neuropathy in the lower extremities. The peroneal nerve is usually compressed at the lateral aspect of the fibular head. Compression by ganglion cysts are one of the numerous underlying etiologies for peroneal nerve neuropathy and are most frequently located around the fibular neck and proximal tibiofibular joint. To the best of our knowledge, this is the first report of an extraneural ganglion cyst located at the level of the distal thigh that resulted in compressive peroneal neuropathy.
We report a case of a 56-year-old man with sudden onset of left foot drop and gait disturbance caused by an extraneural ganglion cyst located in the popliteal fossa.
Electrodiagnosis (EDX) suggested a peroneal nerve lesion. Subsequently, diagnostic ultrasonography (USG) revealed a cystic mass located within the left side of the supracondylar area of femur. Further magnetic resonance imaging confirmed that the mass was located at the proximal of popliteal fossa.
Surgical excision was performed using a direct posterior approach. The cystic mass was compressing the common peroneal nerve, and was carefully and completely removed ensuring that all nerve branches were protected.
A histopathologic evaluation confirmed the diagnosis of a ganglion cyst. There were no postoperative complications. Two months after the surgery, follow-up USG revealed no evidence of cyst recurrence or residual lesions. Six months after the surgery, the ankle dorsiflexor motor power improved and he experienced less pain and hypoesthesia.
Physicians should bear in mind that the peroneal neuropathy can occur because of the ganglion cyst in the distal thigh. The thorough evaluation of EDX and USG is crucial for the early diagnosis and surgical intervention, although there is no abnormal finding around the fibular neck.
腓总神经病变是下肢最常见的周围神经病变类型。腓总神经通常在腓骨头外侧受压。腱鞘囊肿压迫是腓总神经病变众多潜在病因之一，且最常位于腓骨颈和近端胫腓关节周围。据我们所知，这是首例关于位于大腿远端水平的神经外腱鞘囊肿导致压迫性腓总神经病变的报道。
我们报告一例56岁男性患者，因位于腘窝的神经外腱鞘囊肿突然出现左脚下垂和步态障碍。
电诊断（EDX）提示腓总神经损伤。随后，诊断性超声检查（USG）显示股骨髁上区域左侧有一囊性肿块。进一步的磁共振成像证实该肿块位于腘窝近端。
采用直接后路进行手术切除。囊性肿块压迫腓总神经，小心完整切除，确保所有神经分支得到保护。
组织病理学评估确诊为腱鞘囊肿。无术后并发症。术后两个月，随访超声检查未发现囊肿复发或残留病变的证据。术后六个月，踝关节背屈肌肌力改善，疼痛和感觉减退减轻。
医生应牢记，大腿远端的腱鞘囊肿可导致腓总神经病变。尽管腓骨颈周围无异常发现，但EDX和USG的全面评估对早期诊断和手术干预至关重要。
