Favorable outcome after radical resection and subsequent local irradiation of malignant peripheral nerve sheath tumor in the cervical spine

A sporadic pediatric case of a spinal dumbbell-shaped epithelioid malignant peripheral nerve sheath tumor with a novel germline mutation in SMARCB1: a case report and review of the literature

Malignant peripheral nerve sheath tumors (MPNSTs) are commonly associated with poor prognosis and are primarily caused by germline mutations in the SMARCB1/INI-1 gene. However, these tumors are rarely found in the spine. This case report presents the case of a 3-year-old boy diagnosed with a lumbosacral dumbbell-shaped epithelioid MPNST, an extremely uncommon manifestation. Immunohistochemistry revealed the complete absence of the SMARCB1/INI-1 protein, and genetic testing identified a novel germline mutation in the SMARCB1/INI-1 gene in both the patient and his father, suggesting a "second-hit loss." One year of follow-up after the tumor's radical resection revealed no suspected metastasis. This case report offers novel genetic research results regarding spinal dumbbell-shaped MPNSTs. Six studies, including 13 cases associated with spinal dumbbell MPNST, were included in the literature. The range of age of these patients varied from 2 to 71 years. Of the 12 known patients diagnosed with spinal dumbbell MPNST, only one received radiation therapy, while the rest underwent surgery. Two patients who underwent partial resection had metastases after surgery, while one of the five patients who underwent complete surgical resection alone had no distant metastases and a good prognosis, indicating that radical resection is more likely to be effective in inhibiting distant metastasis and improving the prognosis.

Need for arthrodesis following facetectomy for spinal peripheral nerve sheath tumors: an institutional experience and review of the current literature

OBJECTIVE

Spinal peripheral nerve sheath tumors (PNSTs) are a group of rare tumors originating from the nerve and its supporting structures. Standard surgical management typically entails laminectomy with or without facetectomy to gain adequate tumor exposure. Arthrodesis is occasionally performed to maintain spinal stability and mitigate the risk of postoperative deformity, pain, or neurological deficit. However, the factors associated with the need for instrumentation in addition to PNST resection in the same setting remain unclear.

METHODS

An institutional tumor registry at a tertiary care center was queried for patients treated surgically for a primary diagnosis of spinal PNST between 2002 and 2016. An analysis focused on patients in whom a facetectomy was performed during the resection. The addition of arthrodesis at the index procedure comprised the primary outcome. The authors also recorded baseline demographics, tumor characteristics, and surgery-related variables. Logistic regression was used to identify factors associated with increased risk of fusion surgery.

RESULTS

A total of 163 patients were identified, of which 56 (32 had facetectomy with fusion, 24 had facetectomy alone) were analyzed. The median age was 48 years, and 50% of the cohort was female. Age, sex, and race, as well as tumor histology and size, were evenly distributed between patients who received facetectomy alone and those who had facetectomy and fusion. On univariate analysis, total versus subtotal facetectomy (OR 9.0, 95% CI 2.01-64.2; p = 0.009) and cervicothoracic versus other spinal region (OR 9.0, 95% CI 1.51-172.9; p = 0.048) were significantly associated with increased odds of performing immediate fusion. On multivariable analysis, only the effect of total facetectomy remained statistically significant (OR 6.75, 95% CI 1.47-48.8; p = 0.025).

CONCLUSIONS

The authors found that total facetectomy and cervicothoracic involvement may be highly associated with the need for concomitant arthrodesis at the time of index surgery. These findings may help surgeons to determine the best surgical planning for patients with PNST.