Sciatic nerve sarcoidosis: utility of magnetic resonance peripheral nerve imaging and treatment with radiation therapy

Abstract

Sarcoidosis may involve both the central and peripheral nervous system, although peripheral nerve manifestations are usually seen late in the disease. In this report, the authors describe a case of sarcoidosis in a 22-year-old woman who presented with a foot drop. Although results of conventional lumbar magnetic resonance (MR) imaging were normal, MR peripheral nerve imaging of the thigh showed a mass in the sciatic nerve indicating tumor. An intraoperative biopsy sample revealed noncaseating granulomas consistent with sarcoid. The patient was treated with steroid drugs to control the manifestations of her disease but exhibited early signs of femoral bone necrosis, which required discontinuation of the steroids. She was then treated with local radiation therapy. At her 2-year follow-up visit the patient demonstrated relief of her symptoms and improvement on MR peripheral nerve imaging. This case demonstrates that sarcoidosis may present with peripheral nerve manifestations. The appearance of a diffusely swollen nerve on MR imaging should prompt clinicians to include sarcoidosis in the differential diagnosis and plan surgery accordingly. Patients who are not responsive to or who are unable to tolerate medical therapy may be treated with radiation therapy.

Ultrasonography of the tibial nerve in vasculitic neuropathy

“…We hypothesize that a vasculitic–granulomatous lesion in the epineurium, as well as intrafascicular edema as a consequence of nerve ischemia and axonal degeneration, are responsible for such localized nerve enlargement based on pathological findings, although the pathogenesis of nerve enlargement in tibial vasculitic neuropathy is uncertain because the affected tibial nerve has rarely been biopsied 8. Granuloma or intrafascicular edema, as seen in our patients, has occasionally been reported in the enlarged nerves of neurosarcoidosis,5 leprosy,11 chronic inflammatory demyelinating polyradiculoneuropathy,9 and hypertrophic mononeuritis 8…”

Inflammatory pseudotumor of nerve: clinicopathological characteristics and a potential therapy

“…The heterogeneous signal characteristics and enhancement observed are likely due to their varied composition of inflammation, fibrosis, fat, and vascularity in the epineurium. Collectively, these imaging features make consideration of most inflammatory processes (including CIDP and sarcoid ( Dailey et al, 2004 ) ) and benign neurogenic tumors (including perineurioma ( Mauermann et al, 2009 ) ), part of the clinical differential diagnosis, unlikely. Indeed, heterogeneity, as seen on MRI pre‐ and post‐contrast sequences, is a frequent feature of malignant peripheral nerve sheath tumors ( Matsumine et al, 2009 ) .…”

Pragmatic guide to peripheral nerve disease and the role of clinical biomarkers

“…Imaging of peripheral nerves with MRI and ultrasound scanning has been explored for over 20 years52 53 and has entered diagnostic guidelines 54 55. Nerve thickening and signal abnormality are present in a variety of genetic56 and acquired57 58 neuropathies, including CIDP57 and acute inflammatory demyelinating polyneuropathy,58 MMNCB,59 POEMS60 and neurolymphomatosis,61 infective neuropathies (especially leprosy)62 and rarely sarcoidosis 63…”