Major-nerve schwannomas versus intramuscular schwannomas

Shimose Shoji

Sugita Takashi

Kubo Tadahiko

Matsuo Toshihiro

Nobuto Hiroo

Tanaka Kumi

Arihiro Koji

Ochi Mitsuo

Acta Radiologica

Background: A schwannoma is a benign peripheral nerve tumor. Predicting the involvement of a nerve on symptoms or MR findings is crucial to the diagnostic process. Purpose: To compare symptoms, MR findings, and histological findings between major nerve schwannomas and intramuscular schwannomas. Material and Methods: Thirty-four patients with 36 schwannomas (29 major nerve schwannomas and 7 intramuscular schwannomas) surgically excised and proven histologically were retrospectively reviewed. Results: Frequencies of the Tinel - like sign, split-fat sign, entering and exiting nerve, and low-signal margin indicate the presence of the nerve and were significantly higher in major nerve schwannomas than in intramuscular schwannomas. In tumor morphological patterns (the target sign, inhomogeneous pattern, and homogeneous pattern), there were no significant differences between major nerve schwannomas and intramuscular schwannomas. Schwannomas showing the target sign histologically tended to be less degenerative. All major nerve schwannomas and 5 intramuscular schwannomas produce some characteristic symptoms and/or MR findings, but two intramuscular schwannomas didn't have any characteristic symptoms and findings. Conclusion: In major nerve schwannomas, the Tinel - like sign, split-fat sign, entering and exiting nerve, and low-signal margin are commonly observed and useful for diagnosis. In intramuscular schwannomas, these characteristic findings are less common, which makes diagnosis difficult.

Schwannoma

Major nerve

Intramuscular

Target sign

MRI

Tinel-like sign

Medical sciences [ 490 ]

eng

Informa Healthcare

Copyright (c) 2007 Taylor & Francis.

This is an electronic version of an article published in "Acta Radiologica, Volume 48, Issue 6 (2007) pages 672 - 677" Natural Product Research is available at: http://dx.doi.org/10.1080/02841850701326925

[ISSN] 0284-1851

[DOI] 10.1080/02841850701326925

[PMID] 17611877

[NCID] AA10668717

[DOI] http://dx.doi.org/10.1080/02841850701326925