A rare cause of sciatica: Sciatic nerve schwannoma

Abstract

The authors report one case of schwannoma located in the sciatic nerve, just above the popliteal fossa. A sciatic localization is rare, observed in 1% of the patients. The misleading clinical presentation of this localization causes a delay in diagnosis. Magnetic Resonance Imaging (MRI) is the imaging modality of choice, but the final diagnosis is made by the histological examination of the tumor. Schwannoma should be surgically removed without division of the nerve trunk.

Schwannoma of the Sciatic Nerve as a Cause of Extra-articular Knee Pain: Case Report and Literature Review

“…They are described in the literature using different names, such as schwannoma and neurilemoma. Other synonymous names described include neurilemoma, neurinoma neurocytoma, peripheral glioma or perineurial fibroblastoma, peripheral glioma, and schwannoma since it was identified in 1908 by Verocay [ 4 ]. May be associated with syndromes such as neurofibromatosis types 1 or 2, multiple endocrine neoplasia, type II, and the carney complex [ 7 , 8 , 9 ].…”

“…Benign sciatic nerve schwannomas are usually isolated, solitary, well-circumscribed, and well-capsulated tumors and are rarely in the plexiform [ 3 , 10 ]. Lower limb extremities schwannoma is commonly found in the posterior tibial nerve, and involvement of sciatic nerve schwannoma is rare at 1% [ 4 , 10 , 11 ]. It has an incidence of 0.3–04/100.000 cases per year [ 12 ].…”

“…It has an incidence of 0.3–04/100.000 cases per year [ 12 ]. There are 72 previous reported cases of lower limb sciatic nerve schwannoma that we identified from the literature review from the past 51 years until December 2020 [ 1 , 3 , 4 , 5 , 6 , 8 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ].…”

“…T2-weighted MRI will show a hyperintense signal of the mass and a heterogeneous or homogeneous appearance [ 5 , 12 , 15 ]. Maes et al MRI is the imaging modality of choice [ 4 ]. Plain radiography and nerve conduction studies are not often helpful [ 16 ].…”

“…They are isolated, solitary, well-circumscribed, and well-capsulated tumors and are rarely in the plexiform [ 1 , 3 ]. Lower limb benign schwannoma of the sciatic nerve accounts for <1% of all schwannomas [ 2 , 4 ]. These tumors usually present between the 3rd and 5th decades of life [ 5 ].…”