Malignant peripheral nerve sheath tumor of non-neurofibromatosis type I metastasized to the cerebrospinal axis

Abstract

A malignant peripheral nerve sheath tumor (MPNST) is a type of sarcoma that arises from peripheral nerves or cells of the associated nerve sheath. This tumor most commonly metastasizes to the lung and metastases to the spinal cord and brain are very rare. We describe a case of young patient with spinal cord and brain metastases resulting from MPNST. An 18-year-old man presented with a 6-month history of low back pain and radiating pain to his anterior thigh. Magnetic resonance imaging showed a paraspinal mass that extended from the central space of L2 to right psoas muscle through the right L2-3 foraminal space. The patient underwent surgery and the result of the histopathologic study was diagnostic for MPNST. Six months after surgery, follow-up images revealed multiple spinal cord and brain metastases. The patient was managed with chemotherapy, but died several months later. Despite complete surgical excision, the MPNST progressed rapidly and aggressively. Thus, patients with MPNST should be followed carefully to identify local recurrence or metastasis as early as possible.

Keywords: Brain metastasis; Malignant peripheral nerve sheath tumors; Spinal cord metastasis.

Fig. 1

Pre-operative T1-weighted magnetic resonance imaging (MRI) obtained after contrast administration showing the malignant peripheral nerve sheath tumor extending through the neural foramen to the right psoas muscle. A : Sagittal MRI. B : Axial MRI.

Fig. 2

A : Photomicrographs of the mass demonstrating a spindle cell tumor with high cellularity and a fasciculating growth pattern (hematoxylin and eosin; original magnification ×200). B : Round cells with spindle or fusiform cells appear well a high resolution level (hematoxylin and eosin; original magnification ×400). C : Tumor cells showing immunopositive for S-100 protein (original magnification ×200).

Fig. 3

Post-operative T1-weighted magnetic resonance imaging (MRI) obtained after contrast administration showing gross total resection of the tumor. A : Sagittal MRI. B : Axial MRI.

Fig. 4

Magnetic resonance imaging (MRI) showing spinal cord and brain metastasis of MPNST (6 months after surgery). A : T2-weighted sagittal image showing multiple edematous infiltration of spinal cord. B : Contrast enhanced T1-weighted sagittal image showing multiple tiny enhancing dot lesions. C : T2-weighted sagittal brain MRI showing edematous infiltration on pons and medulla. D and E : Contrast enhanced T1-weighted sagittal and axial images showing small enhancing lesions in the right upper pons. MPNST : malignant peripheral nerve sheath tumor.