When biopsy goes wrong: a case series of misdiagnoses and complications from biopsies of masses of unknown origin potentially originating from a peripheral nerve.

OBJECTIVE: Biopsies of peripheral nerve tumors (PNTs) are often used to plan an efficient treatment strategy. However, performing a biopsy is controversial when the mass is likely to be a benign PNT (BPNT). The aim of this study was to evaluate the side effects of biopsies in patients with potential PNTs. METHODS: A retrospective and cross-sectional study was conducted on 24 patients who underwent biopsy of a mass of unknown origin potentially originating from a peripheral nerve (MUOPON), performed in nonspecialty services, and who were later referred to the authors' service for resection of their lesion between January 2005 and December 2022. The patients were evaluated for pain score, presence of a motor or sensory deficit, biopsy diagnosis, and definitive histopathological postsurgical diagnosis. RESULTS: The location of the tumor was supraclavicular in 7 (29.2%) patients, in the axillary region in 3 (12.5%), in the upper limb in 7 (29.2%), and in the lower limb in 7 (29.2%). Twenty-one (87.5%) patients were evaluated by MRI before biopsy, and 3 (12.5%) underwent ultrasound. One patient did not have an examination before the procedure. Based on the biopsy findings, 12 (50%) analyses had an inconclusive histopathological result. The preexisting pain worsened, as measured 1 week after biopsy, in all patients and had remained unchanged at the first evaluation by the authors (median 3 months, range 2-4 months). In 1 case, the open biopsy had to be interrupted because the patient experienced excruciating pain. Four (16.7%) patients developed motor deficits. Subsequent surgery was hampered by scar formation and intratumoral hemorrhage in 5 (20.8%) patients. The initial diagnosis obtained by biopsy differed from the final histopathological diagnosis in all patients, of whom 21 (87.5%) had BPNTs, 2 (8.3%) malignant peripheral nerve sheath tumors, and 1 (4.2%) an ancient schwannoma. CONCLUSIONS: Biopsies of PNTs are controversial and may result in misdiagnosis, neuropathic pain, or neurological deficit due to axonal damage, and they may also hinder microsurgical resection when if performed when not indicated. Indications for biopsy of an MUOPON must be carefully considered, especially if BPNT is a possible diagnosis.

Surgery as an Effective Therapy for Ulnar Nerve Neuropathic Pain Caused by Gunshot Wounds: A Retrospective Case Series.

BACKGROUND: Peripheral nerve injuries remain a major medical problem worldwide and are associated with multiple causes, including gunshot wounds (GSWs), which are the second most common cause of brachial plexus injuries in peacetime and the main, or only, cause reported in wartime studies. The ulnar nerve (UN) is one of the most affected nerves. Peripheral nerve trauma may cause intense neuropathic pain, which is very difficult to control. Particularly UN gunshot injuries may impact individual daily life, as injuries to this nerve result in both sensory and motor deficits within the hand. We evaluated the improvement of neuropathic pain after surgical treatment in a consecutive series of 20 patients with UN injury due to GSWs. METHODS: This single-center, retrospective, consecutive case series included 20 patients with UN injuries due to GSWs, who presented with excruciating neuropathic pain and underwent surgical treatment between 2005 and 2017. RESULTS: Of injuries, 13 occurred in the right upper limb (65%); 12 patients had a high UN injury (60%). Regarding associated injuries, 8 patients had bone injuries (40%), and 4 patients had arterial injuries (20%). A neuroma in continuity was detected in 8 cases (40%), and 4 patients (20%) had shrapnel lodged within the UN. All patients had severe neuropathic pain and functional deficit, with a mean visual analog scale score of 8.45 ± 1.4 and a mean reduction of 6.95 points 12 months after surgery; 10 patients (50%) had a British Medical Research Council score ≥M3. CONCLUSIONS: Surgery is an effective treatment for neuropathic pain from GSWs. Early isolated external neurolysis is associated with better pain management and functional outcomes postoperatively.