Peripheral nerve tumors

Primary brachial plexus tumors: imaging, surgical, and pathological findings in 25 patients

Object

The authors report on the treatment of primary brachial plexus tumors in 25 patients at the University of California, San Francisco. They compare their findings with those obtained in similar series.

Methods

The authors reviewed the electronic and medical records, radiological images, operative reports, and pathological findings in 25 consecutive cases of primary brachial plexus tumors. Cases of metastatic lesions or adjacent neoplasms extending into and involving the brachial plexus were excluded.

At presentation patients ranged in age from 19 to 71 years (mean 47 ±15 years), and neurofibromatosis was present in eight patients (32%). Presenting signs and symptoms included palpable mass (60%), numbness/paresthesias (44%), radiating pain (44%), local pain (16%), and weakness (12%). Duration of symptoms ranged from 2 months to 10 years. Neuroimaging revealed lesions ranging widely in size (volume ~1 to >100 ml). Pathological diagnoses included schwannoma (15 [60%]), neurofibroma (five [20%]), malignant peripheral nerve sheath tumor (four [16%]), and desmoid tumor (one [4%]).

Conclusions

Primary tumors arising in the brachial plexus are rare. Careful workup, surgical technique, and attention to pathological diagnosis optimize management.

Neural sheath tumors of major nerves

Over a 22-year period, operations were performed on 263 patients for 288 primary benign tumors of major peripheral nerves. The tumors included 85 schwannomas, 197 neurofibromas, and six plexiform neurofibromas. Total removal was achieved in 83 of the 85 schwannomas, and 76 of these patients were available for follow-up evaluation. Motor function either improved or was unchanged in 87% of these patients and 85% of those with pain in the distribution of the involved nerve had either total or partial resolution of their symptoms. Of the neurofibromas, 123 occurred in 121 patients without von Recklinghausen's disease. All tumors within this group were completely excised using a fascicular approach to the tumor. Of the 99 patients available for follow-up evaluation, 90% had either improved or unchanged motor function and 88% had partial or complete resolution of pain syndromes. Fifty-nine patients with von Recklinghausen's disease had 80 tumors removed: 74 fusiform tumors (58 of which were completely removed) and six plexiform tumors. Forty-eight of the 58 patients with gross total removal of fusiform tumors were available for follow-up evaluation, of whom 83% had improved or unchanged motor function and 74% had partial or complete resolution of pain syndromes. All six patients with plexiform tumors had progression of symptoms postoperatively. One brachial plexus schwannoma recurred and was re-excised without subsequent recurrence at the 5-year follow-up evaluation. Several incompletely excised plexiform neurofibromas have recurred with a symptomatic presentation.

Operative management of selected brachial plexus lesions

A 12-year operative experience with 171 consecutive patients with severe brachial plexus lesions who had at least 1 1/2 years of follow-up review is analyzed. Selection for and timing of operation was helped by categorization of each individual plexus element as "completely" or "incompletely" injured and as "in continuity" or "not in continuity." Results for each element could be given a single grade by a system which defined that element's proximal and distal input. For most lesions in continuity, an operative delay of several months is advocated so that intraoperative electrical evaluation can be used. Thus, in 282 gunshot wounded and stretch-injured elements of which 210 were thought to be clinically complete, 63 were spared resection because of nerve action potentials (NAP's) found at intraoperative testing, and 57 recovered function with only neurolysis. Elements resected (120) were confirmed as neurotmetic both by intraoperative electrical and subsequent histological studies. Acceptable results were achieved in 16 of 24 sutures, in 43 of 89 grafts, and in each of seven split repairs. Upper trunk and lateral and posterior cord elements fared better than lower trunk and medial cord lesions unless the latter were shown, with evidence of NAP's, to be regenerating and could be spared resection. Some stretched elements could, however, not be repaired, even though an attempt was made to exclude such cases from operation. Lacerations to the brachial plexus where continuity is lost are best repaired primarily if the injury is sharp; in this series, 14 of 18 elements having such repair recovered, whereas in 37 elements with secondary repair, grafts were often necessary and only 50% recovered function. Although associated with skin lacerations, 17 elements with complete loss were in continuity, and six of these were shown to be regenerating and were not resected. Despite intraneural location, large size, and prior operation, many benign tumors (including neurofibromas) can be removed without significant loss by use of the surgical loupes or microscope and repetitive NAP recording. Surgery for selected brachial plexus lesions is worthwhile.