Image-guided percutaneous biopsy of peripheral nerve tumors of indeterminate nature: risks and benefits

Usual management of peripheral nerve tumors is to avoid biopsy in those that are likely benign; the risk of biopsy outweighs the benefit of definitive tissue diagnosis. Biopsy of presumed malignant lesions is performed widely. There is a subset of peripheral nerve tumors that are not easily categorized as benign or malignant based on the clinical and/or radiological features alone. The role of biopsy in peripheral nerve tumors of uncertain character remains controversial and the risk of biopsy (and the potential risk/benefit ratio) for these lesions is not known.

Following approval by our institutional review board, we reviewed all notes of a single peripheral nerve surgeon from 2000 to 2018 with respect to image-guided percutaneous biopsy of nerve tumors. We divided these patients into 3 groups based on clinicoradiologic features. We determined the risk of complications and the "hit rate" for patients with peripheral nerve tumors of uncertain behavior, defined as the percentage of patients sent for percutaneous biopsy who had a malignancy on their final pathology.

Of 82 patients with tumors of uncertain behavior, 9 had complications, and 23 had malignant final pathology (a "hit rate" of 27.7%). Neurosurgical referral for biopsy of tumors of uncertain behavior was made in 60 patients. Twenty-two had malignant final pathology ("hit rate"= 36.7%). Non-neurosurgical referral for biopsy was made in 22 patients with tumors of uncertain behavior. Two had malignant final pathology ("hit rate"= 4.55%). There was a statistically significant difference between the "hit rate" for the two groups (p = 0.021).

The decision to biopsy a peripheral nerve tumor is largely based on the presumed behavior and prognosis, determined via clinicoradiologic characteristics. Patient care might be improved by delaying percutaneous biopsy of peripheral nerve lesions until after a neurosurgical evaluation.