Intraneural perineuriomas: diagnostic value of magnetic resonance neurography

Abstract

Intraneural perineurioma (IP) is an under-recognized hypertrophic peripheral nerve tumor. It affects young patients involving frequently the sciatic nerve and its branches and presents with a progressive, painless and predominantly motor deficit. Magnetic resonance neurography (MRN) is a useful tool to localize the lesion, evaluate its extension, and discriminate between different etiologies. We reviewed the clinical records of 11 patients with pathologically confirm IP. Eight patients were males with mean age 19 years. Initial complains were unilateral steppage (seven patients), bilateral steppage (one patient), unilateral gastrocnemius wasting (one patient), unilateral thigh atrophy (one patient), and unilateral hand weakness (one patient). Nine patients had mild painless sensory loss. Examinations revealed involvement of sciatic nerve extending into the peroneal nerve (eight patients), posterior tibial nerve (one patient), radial nerve (one patient), and femoral nerve (one patient). MRN revealed enlargement of the affected nerve isointense on T1-weighted, hyperintense on T2 fat-saturated images, and with avid enhancement on post-contrast imaging. In all patients, a nerve biopsy confirmed the diagnosis. MRN allows early and non-invasive identification of this tumor and is a key tool providing localization and differential diagnosis in patients with slowly progressive focal neuropathies.

Updates in Musculoskeletal Imaging

“…MRI complements electrodiagnostic testing (EDX) for the evaluation of peripheral neuropathies and is comparatively noninvasive, painless, potentially less prone to interobserver reliability, and can often accurately localize the site of focal pathology. 29,41 Precise localization can potentially save hours in the operating room and decrease patient morbidity associated with extensive nerve exploration. MRI also affords concomitant assessment of all regional muscles within a prescribed field of view when evaluating for denervation, whereas EDX involves direct needle electromyography of each individual muscle.…”

T2 mapping of the distal sciatic nerve in healthy subjects and patients suffering from lumbar disc herniation with nerve compression

“…The sciatic nerve has regularly been under investigation by means of MRN. However, until recently, primarily qualitative MRN has been carried out, with the signal of the sciatic nerve or its morphology being altered in the context of different pathologic conditions such as traumatic or iatrogenic injury and tumors such as perineuriomas [ 5 – 8 ], Fabry disease [ 9 – 11 ], CMTD [ 12 ], or diabetic and other neuropathies [ 13 , 14 ]. Importantly, (semi-)quantitative MRN might be more objective and potentially more robust and reproducible when compared to mere qualitative MRN, with DTI, for instance, being capable of contributing with quantitatively assessable changes by means of diffusion parameters that have already been evaluated among patients with muscular disorders such as myotonic dystrophy [ 15 ], radiculopathy [ 16 ], CIDP [ 17 ], CMTD [ 18 ], or different kinds of neuropathies [ 19 – 21 ].…”

“…Using qualitative MRN and structural evaluations, the sciatic nerve has shown to be affected in various pathologies, such as hamstring injury due to different causes [ 5 ], injection injury after iatrogenic intramuscular infiltrations [ 6 ], injury related to hip replacement surgeries [ 7 ], perineuriomas [ 8 ], Fabry disease [ 9 – 11 ], hereditary motor and sensory neuropathies such as Charcot–Marie–Tooth disease (CMTD) [ 12 ], or diabetic and other neuropathies [ 13 , 14 ]. These studies conducted primarily visual inspections of the sciatic nerves to detect changes in signal intensities, discontinuities, or lesion loads, often together with evaluations of morphological nerve sizes and volumes [ 5 – 14 ].…”

Nerve biopsy in acquired neuropathies

“…Thus, this case demonstrates the usefulness of MRI and ultrasonography as tools in the diagnostic work-up of mononeuropathies, also assisting to identify the ideal site for biopsy. 54 Fusiform nerve enlargement with preserved fascicular architecture can be seen in lipomatosis, schwannoma, neurofibroma, and intraneural perineurioma. 55 Some suggest that a classical clinical presentation with typical MRI findings and nerve conduction studies can make the diagnosis of perineurioma alone.…”