Case Reports
Malignant Peripheral Nerve Sheath Tumor of the Lumbar Spine
Am J Orthop. 2009 May;38(5):E89-E92
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Brent K. Ogawa, MD, David L. Skaggs, MD, and Robert M. Kay, MD
Dr. Ogawa is Fellow, Roger A. Mann Foot and Ankle Fellowship, Oakland, California.
Dr. Skaggs is Associate Professor, and Dr. Kay is Associate Professor, Children's Orthopaedic Center, Children's Hospital Los Angeles, Los Angeles, California, and Keck–University of Southern California School of Medicine, Los Angeles, California.
Abstract not available. Introduction provided instead.
Malignant peripheral nerve sheath tumors (MPNSTs) are rare in children. MPNSTs arise from peripheral nerves or show differentiation of nerve sheath elements, including Schwann cells, fibroblasts, and perineural cells. The term malignant peripheral nerve sheath tumor has replaced older terms, such as malignant schwannoma, neurofibrosarcoma, and neurogenic sarcoma. Incidence of MPNST ranges from 2% to 13%.1 MPNSTs account for approximately 5% to 10% of all soft-tissue sarcomas.
Depending on its location and amount of nerve involvement, MPNST can present as a painful or painless mass. MPNSTs that arise from major nerves can cause sensory and motor symptoms, such as pain, paresthesia, and weakness. Most arise in association with major nerve trunks, such as the brachial or sacral plexus or sciatic nerve. Approximately 50% arise in the trunk, 30% in extremities, and 20% in the head and neck.2 Compared with patients who do not have neurofibromastosis type 1 (NF-1), patients with NF-1 have a central distribution of primary tumors.3 An association between MPNST and NF-1 has been well documented.1-20 Patients with NF-1 and MPNST tend to be younger (28.7 years) than patients who have MPNST without NF-1 (39.7 years).4 Prior radiation therapy has also been well documented as an important risk factor in development of MPNST.3,7,8,16,18 Wong and colleagues7 reported that, in 10% of their patients, radiation given for prior unspecified tumors induced MPNST.
MPNSTs often are difficult to diagnose and behave aggressively. Treatment includes wide surgical resection. Adjuvant therapy is advocated by some authors, though the results are mixed. Tumor size, patient age, tumor necrosis, and presence of neurofibromatosis can negatively affect survival. Despite appropriate treatment, recurrence is high and prognosis poor.
We describe the case of a lumbar-spine MPNST that presented as chronic knee pain in a boy. The patient had many of the typical signs and symptoms of an intraspinal tumor, which facilitated appropriate diagnosis and treatment. Such signs and symptoms should be sought in children who present with neurogenic pain.