Percutaneous image-guided biopsy in malignant peripheral nerve sheath tumors

The decision to biopsy a peripheral nerve tumor is largely based on its presumed behavior and prognosis, determined by patient history, clinical exam, and radiologic characteristics. Percutaneous image-guided biopsy is not without risk in patients with malignant peripheral nerve sheath tumors (MPNSTs); in particular, there may be concern regarding worsening neurologic function, increasing neuropathic pain, and incorrect or absent diagnosis.

Following approval by our institutional review board, we reviewed records from 1990 to 2019 at our institution's three main sites ("our institution"). Patients with pathology-proven MPNST were selected. Further inclusion criteria included image-guided percutaneous biopsy performed at our institution, pathology report available for review, and follow-up documentation to determine post-biopsy complications.

Three hundred thirty-one patients with MPNST were reviewed. In total, 73 patients undergoing image-guided percutaneous biopsies were included. Twenty-two (30.1%) had biopsy-related complications. This included ten patients with misdiagnosis (13.7%) and six patients with non-diagnostic biopsies (8.2%). Six patients had new or worsened pain that resolved with time and neuropathic pain medication (8.2%), and one patient had subjectively worsened proximal weakness (1.3%) which resolved.

We found nearly a third of patients undergoing biopsy had a biopsy-related complication. The single largest complication was the inability to obtain an accurate diagnosis (21.9%) with the first biopsy. This may lead to the need for repeat percutaneous or open biopsies, or a non-oncologic initial surgery with implications for disease-free and overall survival. Neurologic complications including exacerbation of pain or a deficit were rare and transient. It remains important that clinicians balance the potential risks and benefits based on individual patient characteristics when determining the necessity of an image-guided percutaneous biopsy.