LETTER

Hippokratia 2018, 22(2):91

Milenković SS, Mitković MM
Clinic for Orthopedic surgery and Traumatology, Clinical Centre of Nis, Medical faculty, University of Nis, Nis, Serbia

 

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Key words: Schwannoma, common peroneal nerve 

Corresponding author: Sasa Milenkovic, University Orthopedic & Traumatology Clinic Nis, Clinical center Nis, 48 Bul. Dr Zorana Djindjica, 18000, Nis, Serbia, tel: +38163428791, e-mail : This email address is being protected from spambots. You need JavaScript enabled to view it.

 

Dear Editor,

Schwannomas (neurilemomas) are benign tumors of peripheral nerves that originate from Schwann cells. They were first described by the Verocay in 19081. Cases of common peroneal nerve schwannomas are rarely reported in the literature2.

A 41-year-old man presented with intermittent left knee pain of five months duration, and paresthesia of the lower posterolateral, anterolateral leg, and dorsum of the foot of three months duration. He experienced increased pain with passive and active dorsiflexion. Motor function of the deep and superficial peroneal nerves was normal. Physical examination revealed a palpable tumor mass on the posterolateral aspect of his left knee. Therefore, a magnetic resonance imaging (MRI) scan of his left knee was performed, which showed a well-defined tumor mass of the posterolateral aspect of the knee (Figure 1A). The patient underwent surgery under spinal anesthesia with tourniquet use. The tumor was exposed via a lateral surgical approach (Figure 1B) and was excised in toto after careful dissection of the perineurium (Figure 1C). Macroscopic nerve integrity was maintained during the procedure. Postoperatively he suffered no neurological complication. The excised specimen (measuring 3 x 2.5 cm) was sent for histopathology which showed to be benign nerve Schwannoma.



Figure 1: A) Sagittal images of magnetic resonance imaging of the left knee of 41-year-old man presenting with intermittent left knee pain, showing a well-defined tumor mass of the posterolateral aspect of the knee; B) Surgical exposure of the common peroneal nerve schwannoma via a lateral surgical approach excision; C) Tumor excision in toto after careful dissection of the perineurium with preservation of the macroscopic nerve integrity.

Schwannomas are the most common benign peripheral nerve sheath tumors with less than one percent chance of malignant transformation. Schwannomas of the peroneal nerve are very rare, and one can find in the literature only a few cases in the last 20 years3. Treatment of these tumors requires surgical excision with careful dissection and preservation of the nerve. Cases of peroneal nerve injury following surgical excision are not uncommon resulting in foot drop and such complications after surgical excision have been described in the literature4,5. Three months after the surgery our patient recovered completely and was able to walk without assistance and his complaints of pain and paresthesia fully resolved.

Conflict of interest

Authors declare no conflict of interest.

References

1. Zhou J, Man XY, Zheng M, Cai SQ. Multiple plexiform schwannoma of a finger.  Eur J Dermatol. 2012; 22: 149-150.
2. Sharig O, Radha S, Konan S. Common peroneal nerve schwannoma: an unusual differential for a symptomatic knee lump. BMJ Case Rep. 2012; 2012: pii: bcr2012007346.
3. Tan JA, Levin KB, Rhani SA, Hisam A. Schwannoma of the common peroneal nerve - A rare incidence. J Surg Academia. 2017; 7: 24-27.
4. Rafai MA, El Otmani H, Rafai M, Bouhaajaj FZ, Largab A, Trafeh M, et al. [Peroneal nerve schwannoma presenting with a peroneal palsy]. Rev Neurol (Paris). 2006; 162: 866-868.
5. Kim SM, Seo SW, Lee JY, Sung KS. Surgical outcome of schwannomas arising from major peripheral nerves in the lower limb. Int Orthop. 2012; 36: 1721-1725.