UNIQUE BENIGN TUMOURS OF PERIPHERAL NERVES: RETROSPECTIVE ANALYSIS OF 51 CASES

Abstract

Purpose: Isolated tumours of the peripheral nerves are exceptional and benign in 90% of the cases. They develop from the constitutive elements of the nerve and correspond to schwannomas in 80% of cases. Other tumours are much more rare and exhibit wide histological variability.

Material and methods: Fifty-one patients were reviewed at mean 4.6 years. Forty-one had a resectable tumour: schwannoma (n=39), intranervous lipoma (n=2). Ten an unresectable tumour: solitary neurofibroma (n=5), peri-nervous hemangioma (n=3), neurofibrolipoma (n=2). We detailed the type of lesion, diagnostic elements, and results of complementary explorations. Enucleation was performed for resectable tumours. Epineurotomy for decompression with systematic interfascicular biopsy was performed in the event of an unresectable tumour.

Results: Postoperative neurological deficits were exceptional and transient. In a first case, prognosis was excellent due to the absence of recurrence or degeneration. In the second, neurological disorders persisted but decreased (paraesthesia). The course remained stable.

Discussion: Our findings are in line with reports in the literature. The diagnosis of nerve tumour should be entertained in the event of tumefaction along a nerve trajectory or if palpation triggers pain. MRI is the most powerful complementary exploration, particularly for deep tumours. The nature of the tumour, its benignity, and the possibility for resection can be suspected on the basis of clinical and complementary findings, but surgery and pathology examination of the surgical specimen are required for confirmation. Preservation of nerve continuity is the key to the therapeutic approach. For resectable tumours, exceptional persistence of symptoms should be followed by a new exploration to search for small unrecognised tumour(s) at the same operative site. For all other cases, recent and rapid changes in the clinical presentation is a sign of recurrence and requires appropriate intervention. To our knowledge, malignant degeneration has never been observed.

Conclusion: First-intention resection of a nerve with a nerve tumour is never indicated.