Tumors of peripheral nerves: correlation of symptoms, clinical signs, imaging features, and histologic diagnosis

Objective. To distinguish between benign and malignant tumors in the peripheral nerves. Design and patients. The clinical, imaging and histologic findings of 99 benign and 16 malignant tumors in the peripheral nerves were reviewed retrospectively. Results. Preoperative motor weakness was observed in only six of 99 benign tumors and was mild, while slight to severe motor weakness was present in 15 of 16 malignant lesions. Pain at rest was present in five of 99 benign tumors and in 15 of 16 malignant tumors. All benign lesions showed a smooth tumoral margin, while half the malignant lesions showed an invasive margin on CT or MRI. Thirteen of 28 benign lesions on CT and nine of 23 on MRI showed round to geographic central enhancement, but this pattern was not seen in malignant lesions. Conclusion. Absence of severe motor weakness and a central enhancement pattern strongly suggest a benign nature, while severe rest pain and invasive tumor margin suggest malignant lesions in peripheral nerve tumors. Received: 30 July 1998 Revision requested: 30 October 1998 Revision received: 30 November 1998 Accepted: 12 January 1999