Not all cervical masses are ganglions. A case series of 24 patients presenting benign brachial plexus tumors with emphasis on 5 biopsied patients and review of literature.

Introduction: Benign nerve sheath tumors of the brachial plexus (bBPNST) are rare entities that can mimic more common cervical or axillary pathologies such as lymphadenopathy. Research question: How to avoid an unnecessary and risky biopsy of a bBPNST? Patients and methods: We retrospectively reviewed 24 patients with bBPNST. We analyzed the clinical presentation, radiological findings, therapeutic management, with a particular focus on a subgroup of 5 patients who underwent a percutaneous biopsy before neurosurgical consultation. Results: The most common presentations were radiating pain and a palpable mass. MRI well showed the supraclavicular (n = 19) or infra-clavicular (n = 5) tumor whose mean largest diameter was 37 mm. 21 patients underwent surgery. Gross total resection (GTR) was achieved in 19 and subtotal resection (STR) in 2. Postoperative outcomes were favorable, although 2 patients developed a new motor deficit. Among the 5 biopsied patients (7 biopsies in total), only one had a history of cancer. Biopsy-related morbidity included severe neuropathic pain in 2 patients and a new motor deficit in 1. All subsequently underwent surgery (1GTR, 1STR). Postoperative outcomes included two cases of transient motor deficit. One of the 2 patients who had undergone 2 biopsies developed a huge fibro-inflammatory reaction, requiring reoperation at postoperative day 7 for suspected hematoma and developed 2 years later tumor recurrence needing reoperation. Discussion and conclusion: Diagnosis of a bBPNST relies on clinical suspicion, careful clinical examination (mass, Tinel's sign), and MRI. Percutaneous biopsy of a suspected bBPNST provides limited diagnostic benefit and may expose patients to iatrogenic complications.