What Else Is Back There?

Abstract

PresentationChronic back pain is a condition often seen by the internist and rarely requires further testing. When pain is intractable, however, other rare potential causes may need to be evaluated.A 47-year-old Caucasian man with history of chronic back pain presented to our facility for evaluation of sudden-onset, severe, mid-thoracic back pain that radiated around to his chest and was worsened by any movement. No trauma was associated with the pain, which had started the previous day. He had experienced a similar pain episode 3 months previously and had been evaluated by a chiropractor, who determined the cause to be musculoskeletal. The pain had resolved with physical therapy.The patient denied any constitutional symptoms, chest pain, shortness of breath, limb weakness, paresthesias, numbness, or bowel or bladder dysfunction. No other significant past medical or family history was noted. He denied any alcohol, tobacco, or illicit drug use.AssessmentUpon evaluation, the patient had a temperature of 36.3°C, heart rate of 60 beats/min, blood pressure of 114/80 mm Hg, respiratory rate of 20 breaths/min, and oxygen saturation of 100% on room air. The severe pain (10/10 severity) was causing him acute distress. A musculoskeletal exam was remarkable for significant midline T2-T7 tenderness, as well as left paraspinal T4-T6 tenderness. The physical exam was otherwise unremarkable.In laboratory studies, the patient's electrolyte levels and complete blood count were normal. The erythrocyte sedimentation rate was 12 mm/L·h (reference, 0-22 mm/L·h), and the C-reactive protein level was less than 3.0 mg/L (reference,<8.0 mg/L). Chest and thoracic spine x-rays were completely unremarkable.Toradol and morphine were administered intravenously to treat for acute exacerbation of chronic back pain. However, when the pain remained uncontrolled after 2 hours, the patient was sent for further workup. Contrast computed tomography (CT) imaging of the thoracic spine revealed multiple subpleural soft-tissue densities along the inferior aspect of the T5-T8 ribs in the location of the intercostal nerves, suggestive of neurogenic tumors (Figure 1). The patient was admitted to the general medicine service for pain control and further imaging to better characterize the masses. Magnetic resonance imaging (MRI) of the thoracic spine with gadolinium showed multiple T1-weighted isointense (Figure 2) and T2-weighted hyperintense (Figure 3) masses with no enhancement arising from the T4-T9 intercostal nerves bilaterally.Figure 2Thoracic axial MRI T1-weighted image with contrast (T6 level) showing bilateral isointense masses (red circles) suggestive of peripheral nerve sheath tumors in the same region shown in the previous CT scan.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Figure 3Thoracic axial MRI T2-weighted image (T6 level) showing bilateral hyperintense masses (red arrows) in the same plane and location as demonstrated in (Figure 2), confirming the presence of peripheral nerve sheath tumors.View Large Image Figure ViewerDownload Hi-res image Download (PPT)DiagnosisThe MRI findings strongly suggested that the patient had intercostal peripheral nerve sheath tumors. Data on the overall incidence of peripheral nerve sheath tumors is lacking, but only a very small fraction of these tumors occur in the intercostal area.The signs and symptoms of peripheral nerve sheath tumors will vary depending on the location, degree, and amount of nerve affected by the tumors. They may present with a mass, paresthesias, or, if they develop near the surface of the skin, allodynia. If more interior, the symptoms may include nerve impingement with sharp, lightening-like radicular pain, muscle weakness, or paralysis. The age of the patient; the presence of peripheral nerve lesions, prior malignancies, or a history of radiation therapy; and family genetic history can help narrow the diagnosis. If the clinical suspicion of peripheral nerve sheath tumors is high, a thorough screen for neurofibromatosis types 1 and 2, which can affect the rate of malignant transformation, should be undertaken. During the physical exam, the clinician should search for hearing difficulties, café-au-lait spots, neurofibromas, Lisch nodules, axillary/groin freckling, and bowing of the legs to suggest the presence of underlying neurofibromatosis.The diversity of presentation of peripheral nerve sheath tumors can lead to a myriad of tests. Nevertheless, imaging will typically be performed to look for a lesion in the area of question. Plain film radiography can elucidate calcium and fat components within the tumor and also can reveal changes associated with nearby skeletal structures1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google Scholar but its diagnostic yield is limited. Furthermore, it can miss tumors that are small or underneath other structures. MRI with gadolinium has slowly replaced CT imaging with contrast as the modality of choice for the evaluation of peripheral nerve sheath tumors because it provides improved detail without possibility of contrast reaction. However, CT imaging is still useful when MRI is contraindicated, when skeletal or calcific tumor changes are being studied, or when the chest and abdomen are being evaluated for metastases.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google ScholarMRI can confirm the presence of a mass while delineating anatomy and spatial orientation, and it poses minimal risk of complications or side effects.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google Scholar Additionally, MRI allows for 3-dimensional reconstruction, which can aid in determination of the extent of the tumor and provide multi-planar geometry that better delineates resectability options. Peripheral nerve sheath tumors usually demonstrate isointense or slightly hyperintense T1-weighted and hyperintense T2- weighted imaging characteristics.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google Scholar After gadolinium administration, these tumors usually, but not always, demonstrate enhancement.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google Scholar However, the tumors can vary in appearance and intensity on MRI from patient to patient and can even vary in the same patient with multiple scans due to motion artifact, uneven fat suppression, or poor signal-to-noise ratio.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google Scholar Thus, even with advances in MRI, it is still limited in conclusively determining the exact pathologic nature of the tumor. However, malignancy can be suggested by features such as metastasis, rapid growth, a tumor size larger than 5 cm, increased metabolic activity (which can be seen by position emission tomography), and a history of previous malignant peripheral nerve sheath tumors.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google ScholarBiopsy is almost always considered when the history, physical exam, and imaging results are congruent with peripheral nerve sheath tumors. Although no standardized diagnostic algorithm has been established, percutaneous biopsy was not favored in the past because it carried a risk of neurologic injury, tumor seeding along the needle track, and scarring that could increase the challenge of definitive surgical removal. However, newer and safer image-guided biopsy techniques for determining surgical resectability and preoperative planning are becoming more readily available at specialized centers. Biopsy findings associated with peripheral nerve sheath tumors include, but are not limited to, schwannoma, neurofibroma, lipoma, chondroma, vascular tumors, or even rarely, lymphoma.2Chatillon C.E. Guiot M.C. Jacques L. Lipomatous, vascular, and chondromatous benign tumors of the peripheral nerves: representative cases and review of the literature.Neurosurg Focus. 2007; 22: E18Crossref PubMed Google ScholarManagementCurrently, if a diagnosis of peripheral nerve sheath tumors is established either clinically (by imaging) or pathologically (by biopsy), 2 major management strategies exist: observation by serial imaging and surgical excision. Chemotherapy remains controversial and is usually considered only in malignant cases.3Perrin R.G. Guha A. Malignant peripheral nerve sheath tumors.Neurosurg Clin N Am. 2004; 15: 203-216Abstract Full Text Full Text PDF PubMed Scopus (71) Google Scholar Because the natural history of peripheral nerve sheath tumors is poorly understood, appropriate criteria for selection of a management option have yet to be established.More than 90% of peripheral nerve tumors are benign.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google Scholar No prospective studies exist, but current estimates place the incidence of malignant peripheral nerve sheath tumors at 0.001 % in the general population; this rate increases to 3-5 % in those with neurocutaneous syndromes.3Perrin R.G. Guha A. Malignant peripheral nerve sheath tumors.Neurosurg Clin N Am. 2004; 15: 203-216Abstract Full Text Full Text PDF PubMed Scopus (71) Google Scholar, 4Ball J.R. Biggs M.T. Operative steps in management of benign nerve sheath tumors.Neurosurg Focus. 2007; 22: E7Crossref PubMed Scopus (17) Google Scholar If the tumors are deemed to be benign, by either imaging or biopsy, conservative observational management by serial MRI is acceptable. The scans will provide information on growth course, lymph node/vascular involvement, invasion of surrounding structures, and metastatic spread. The risks associated with observational management include progressive pain, neurologic dysfunction, and, rarely, malignant transformation.4Ball J.R. Biggs M.T. Operative steps in management of benign nerve sheath tumors.Neurosurg Focus. 2007; 22: E7Crossref PubMed Scopus (17) Google Scholar The patient under observation will require adequate pain control, physical therapy, and good follow-up. If a question of malignant transformation arises either initially or during follow-up, positron emission tomography can detect the increased metabolic rate consistent with malignancies.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google ScholarOf every 1 million people in the US, an average of 6 per year will require surgical intervention for peripheral nerve tumors.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google Scholar Currently, general indications for surgical management include severely symptomatic lesions with pain or neurologic deficit, malignant imaging findings, involvement of a major nerve plexus, or biopsy-confirmed malignancy.4Ball J.R. Biggs M.T. Operative steps in management of benign nerve sheath tumors.Neurosurg Focus. 2007; 22: E7Crossref PubMed Scopus (17) Google Scholar Post-operative adjuvant radiation therapy is indicated for marginally resected tumors; however, for the more common benign tumors, radiation is rarely required. The rare malignant tumors are candidates for postoperative radiation.3Perrin R.G. Guha A. Malignant peripheral nerve sheath tumors.Neurosurg Clin N Am. 2004; 15: 203-216Abstract Full Text Full Text PDF PubMed Scopus (71) Google Scholar, 5Dorsi M.J. Belzberg A.J. Paraspinal nerve sheath tumors.Neurosurg Clin N Am. 2004; 15 (vii): 217-222Abstract Full Text Full Text PDF PubMed Scopus (15) Google ScholarNeurofibromatosis can affect the rate of malignant transformation and subsequently dictate management options not only for the patient, but also quite possibly for the patient's family. Thus, if neurofibromatosis is suspected, a medical geneticist should be consulted sooner rather than later for further diagnostic and chromosomal evaluation.Orthopedic and neurologic surgery services both evaluated our patient for CT-guided biopsy and determined that it was unnecessary because the tumors did not involve the spinal cord, were not compromising neurologic function, and did not demonstrate malignant imaging findings. The pain resolved over the course of a few days with scheduled oral analgesics and inpatient physical therapy, and the patient was discharged with instructions for follow-up surveillance imaging. Outpatient genetic evaluation for neurofibromatosis was negative. The patient continues to do well with physical therapy. PresentationChronic back pain is a condition often seen by the internist and rarely requires further testing. When pain is intractable, however, other rare potential causes may need to be evaluated.A 47-year-old Caucasian man with history of chronic back pain presented to our facility for evaluation of sudden-onset, severe, mid-thoracic back pain that radiated around to his chest and was worsened by any movement. No trauma was associated with the pain, which had started the previous day. He had experienced a similar pain episode 3 months previously and had been evaluated by a chiropractor, who determined the cause to be musculoskeletal. The pain had resolved with physical therapy.The patient denied any constitutional symptoms, chest pain, shortness of breath, limb weakness, paresthesias, numbness, or bowel or bladder dysfunction. No other significant past medical or family history was noted. He denied any alcohol, tobacco, or illicit drug use. Chronic back pain is a condition often seen by the internist and rarely requires further testing. When pain is intractable, however, other rare potential causes may need to be evaluated. A 47-year-old Caucasian man with history of chronic back pain presented to our facility for evaluation of sudden-onset, severe, mid-thoracic back pain that radiated around to his chest and was worsened by any movement. No trauma was associated with the pain, which had started the previous day. He had experienced a similar pain episode 3 months previously and had been evaluated by a chiropractor, who determined the cause to be musculoskeletal. The pain had resolved with physical therapy. The patient denied any constitutional symptoms, chest pain, shortness of breath, limb weakness, paresthesias, numbness, or bowel or bladder dysfunction. No other significant past medical or family history was noted. He denied any alcohol, tobacco, or illicit drug use. AssessmentUpon evaluation, the patient had a temperature of 36.3°C, heart rate of 60 beats/min, blood pressure of 114/80 mm Hg, respiratory rate of 20 breaths/min, and oxygen saturation of 100% on room air. The severe pain (10/10 severity) was causing him acute distress. A musculoskeletal exam was remarkable for significant midline T2-T7 tenderness, as well as left paraspinal T4-T6 tenderness. The physical exam was otherwise unremarkable.In laboratory studies, the patient's electrolyte levels and complete blood count were normal. The erythrocyte sedimentation rate was 12 mm/L·h (reference, 0-22 mm/L·h), and the C-reactive protein level was less than 3.0 mg/L (reference,<8.0 mg/L). Chest and thoracic spine x-rays were completely unremarkable.Toradol and morphine were administered intravenously to treat for acute exacerbation of chronic back pain. However, when the pain remained uncontrolled after 2 hours, the patient was sent for further workup. Contrast computed tomography (CT) imaging of the thoracic spine revealed multiple subpleural soft-tissue densities along the inferior aspect of the T5-T8 ribs in the location of the intercostal nerves, suggestive of neurogenic tumors (Figure 1). The patient was admitted to the general medicine service for pain control and further imaging to better characterize the masses. Magnetic resonance imaging (MRI) of the thoracic spine with gadolinium showed multiple T1-weighted isointense (Figure 2) and T2-weighted hyperintense (Figure 3) masses with no enhancement arising from the T4-T9 intercostal nerves bilaterally.Figure 3Thoracic axial MRI T2-weighted image (T6 level) showing bilateral hyperintense masses (red arrows) in the same plane and location as demonstrated in (Figure 2), confirming the presence of peripheral nerve sheath tumors.View Large Image Figure ViewerDownload Hi-res image Download (PPT) Upon evaluation, the patient had a temperature of 36.3°C, heart rate of 60 beats/min, blood pressure of 114/80 mm Hg, respiratory rate of 20 breaths/min, and oxygen saturation of 100% on room air. The severe pain (10/10 severity) was causing him acute distress. A musculoskeletal exam was remarkable for significant midline T2-T7 tenderness, as well as left paraspinal T4-T6 tenderness. The physical exam was otherwise unremarkable. In laboratory studies, the patient's electrolyte levels and complete blood count were normal. The erythrocyte sedimentation rate was 12 mm/L·h (reference, 0-22 mm/L·h), and the C-reactive protein level was less than 3.0 mg/L (reference,<8.0 mg/L). Chest and thoracic spine x-rays were completely unremarkable. Toradol and morphine were administered intravenously to treat for acute exacerbation of chronic back pain. However, when the pain remained uncontrolled after 2 hours, the patient was sent for further workup. Contrast computed tomography (CT) imaging of the thoracic spine revealed multiple subpleural soft-tissue densities along the inferior aspect of the T5-T8 ribs in the location of the intercostal nerves, suggestive of neurogenic tumors (Figure 1). The patient was admitted to the general medicine service for pain control and further imaging to better characterize the masses. Magnetic resonance imaging (MRI) of the thoracic spine with gadolinium showed multiple T1-weighted isointense (Figure 2) and T2-weighted hyperintense (Figure 3) masses with no enhancement arising from the T4-T9 intercostal nerves bilaterally. DiagnosisThe MRI findings strongly suggested that the patient had intercostal peripheral nerve sheath tumors. Data on the overall incidence of peripheral nerve sheath tumors is lacking, but only a very small fraction of these tumors occur in the intercostal area.The signs and symptoms of peripheral nerve sheath tumors will vary depending on the location, degree, and amount of nerve affected by the tumors. They may present with a mass, paresthesias, or, if they develop near the surface of the skin, allodynia. If more interior, the symptoms may include nerve impingement with sharp, lightening-like radicular pain, muscle weakness, or paralysis. The age of the patient; the presence of peripheral nerve lesions, prior malignancies, or a history of radiation therapy; and family genetic history can help narrow the diagnosis. If the clinical suspicion of peripheral nerve sheath tumors is high, a thorough screen for neurofibromatosis types 1 and 2, which can affect the rate of malignant transformation, should be undertaken. During the physical exam, the clinician should search for hearing difficulties, café-au-lait spots, neurofibromas, Lisch nodules, axillary/groin freckling, and bowing of the legs to suggest the presence of underlying neurofibromatosis.The diversity of presentation of peripheral nerve sheath tumors can lead to a myriad of tests. Nevertheless, imaging will typically be performed to look for a lesion in the area of question. Plain film radiography can elucidate calcium and fat components within the tumor and also can reveal changes associated with nearby skeletal structures1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google Scholar but its diagnostic yield is limited. Furthermore, it can miss tumors that are small or underneath other structures. MRI with gadolinium has slowly replaced CT imaging with contrast as the modality of choice for the evaluation of peripheral nerve sheath tumors because it provides improved detail without possibility of contrast reaction. However, CT imaging is still useful when MRI is contraindicated, when skeletal or calcific tumor changes are being studied, or when the chest and abdomen are being evaluated for metastases.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google ScholarMRI can confirm the presence of a mass while delineating anatomy and spatial orientation, and it poses minimal risk of complications or side effects.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google Scholar Additionally, MRI allows for 3-dimensional reconstruction, which can aid in determination of the extent of the tumor and provide multi-planar geometry that better delineates resectability options. Peripheral nerve sheath tumors usually demonstrate isointense or slightly hyperintense T1-weighted and hyperintense T2- weighted imaging characteristics.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google Scholar After gadolinium administration, these tumors usually, but not always, demonstrate enhancement.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google Scholar However, the tumors can vary in appearance and intensity on MRI from patient to patient and can even vary in the same patient with multiple scans due to motion artifact, uneven fat suppression, or poor signal-to-noise ratio.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google Scholar Thus, even with advances in MRI, it is still limited in conclusively determining the exact pathologic nature of the tumor. However, malignancy can be suggested by features such as metastasis, rapid growth, a tumor size larger than 5 cm, increased metabolic activity (which can be seen by position emission tomography), and a history of previous malignant peripheral nerve sheath tumors.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google ScholarBiopsy is almost always considered when the history, physical exam, and imaging results are congruent with peripheral nerve sheath tumors. Although no standardized diagnostic algorithm has been established, percutaneous biopsy was not favored in the past because it carried a risk of neurologic injury, tumor seeding along the needle track, and scarring that could increase the challenge of definitive surgical removal. However, newer and safer image-guided biopsy techniques for determining surgical resectability and preoperative planning are becoming more readily available at specialized centers. Biopsy findings associated with peripheral nerve sheath tumors include, but are not limited to, schwannoma, neurofibroma, lipoma, chondroma, vascular tumors, or even rarely, lymphoma.2Chatillon C.E. Guiot M.C. Jacques L. Lipomatous, vascular, and chondromatous benign tumors of the peripheral nerves: representative cases and review of the literature.Neurosurg Focus. 2007; 22: E18Crossref PubMed Google Scholar The MRI findings strongly suggested that the patient had intercostal peripheral nerve sheath tumors. Data on the overall incidence of peripheral nerve sheath tumors is lacking, but only a very small fraction of these tumors occur in the intercostal area. The signs and symptoms of peripheral nerve sheath tumors will vary depending on the location, degree, and amount of nerve affected by the tumors. They may present with a mass, paresthesias, or, if they develop near the surface of the skin, allodynia. If more interior, the symptoms may include nerve impingement with sharp, lightening-like radicular pain, muscle weakness, or paralysis. The age of the patient; the presence of peripheral nerve lesions, prior malignancies, or a history of radiation therapy; and family genetic history can help narrow the diagnosis. If the clinical suspicion of peripheral nerve sheath tumors is high, a thorough screen for neurofibromatosis types 1 and 2, which can affect the rate of malignant transformation, should be undertaken. During the physical exam, the clinician should search for hearing difficulties, café-au-lait spots, neurofibromas, Lisch nodules, axillary/groin freckling, and bowing of the legs to suggest the presence of underlying neurofibromatosis. The diversity of presentation of peripheral nerve sheath tumors can lead to a myriad of tests. Nevertheless, imaging will typically be performed to look for a lesion in the area of question. Plain film radiography can elucidate calcium and fat components within the tumor and also can reveal changes associated with nearby skeletal structures1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google Scholar but its diagnostic yield is limited. Furthermore, it can miss tumors that are small or underneath other structures. MRI with gadolinium has slowly replaced CT imaging with contrast as the modality of choice for the evaluation of peripheral nerve sheath tumors because it provides improved detail without possibility of contrast reaction. However, CT imaging is still useful when MRI is contraindicated, when skeletal or calcific tumor changes are being studied, or when the chest and abdomen are being evaluated for metastases.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google Scholar MRI can confirm the presence of a mass while delineating anatomy and spatial orientation, and it poses minimal risk of complications or side effects.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google Scholar Additionally, MRI allows for 3-dimensional reconstruction, which can aid in determination of the extent of the tumor and provide multi-planar geometry that better delineates resectability options. Peripheral nerve sheath tumors usually demonstrate isointense or slightly hyperintense T1-weighted and hyperintense T2- weighted imaging characteristics.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google Scholar After gadolinium administration, these tumors usually, but not always, demonstrate enhancement.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google Scholar However, the tumors can vary in appearance and intensity on MRI from patient to patient and can even vary in the same patient with multiple scans due to motion artifact, uneven fat suppression, or poor signal-to-noise ratio.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google Scholar Thus, even with advances in MRI, it is still limited in conclusively determining the exact pathologic nature of the tumor. However, malignancy can be suggested by features such as metastasis, rapid growth, a tumor size larger than 5 cm, increased metabolic activity (which can be seen by position emission tomography), and a history of previous malignant peripheral nerve sheath tumors.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google Scholar Biopsy is almost always considered when the history, physical exam, and imaging results are congruent with peripheral nerve sheath tumors. Although no standardized diagnostic algorithm has been established, percutaneous biopsy was not favored in the past because it carried a risk of neurologic injury, tumor seeding along the needle track, and scarring that could increase the challenge of definitive surgical removal. However, newer and safer image-guided biopsy techniques for determining surgical resectability and preoperative planning are becoming more readily available at specialized centers. Biopsy findings associated with peripheral nerve sheath tumors include, but are not limited to, schwannoma, neurofibroma, lipoma, chondroma, vascular tumors, or even rarely, lymphoma.2Chatillon C.E. Guiot M.C. Jacques L. Lipomatous, vascular, and chondromatous benign tumors of the peripheral nerves: representative cases and review of the literature.Neurosurg Focus. 2007; 22: E18Crossref PubMed Google Scholar ManagementCurrently, if a diagnosis of peripheral nerve sheath tumors is established either clinically (by imaging) or pathologically (by biopsy), 2 major management strategies exist: observation by serial imaging and surgical excision. Chemotherapy remains controversial and is usually considered only in malignant cases.3Perrin R.G. Guha A. Malignant peripheral nerve sheath tumors.Neurosurg Clin N Am. 2004; 15: 203-216Abstract Full Text Full Text PDF PubMed Scopus (71) Google Scholar Because the natural history of peripheral nerve sheath tumors is poorly understood, appropriate criteria for selection of a management option have yet to be established.More than 90% of peripheral nerve tumors are benign.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google Scholar No prospective studies exist, but current estimates place the incidence of malignant peripheral nerve sheath tumors at 0.001 % in the general population; this rate increases to 3-5 % in those with neurocutaneous syndromes.3Perrin R.G. Guha A. Malignant peripheral nerve sheath tumors.Neurosurg Clin N Am. 2004; 15: 203-216Abstract Full Text Full Text PDF PubMed Scopus (71) Google Scholar, 4Ball J.R. Biggs M.T. Operative steps in management of benign nerve sheath tumors.Neurosurg Focus. 2007; 22: E7Crossref PubMed Scopus (17) Google Scholar If the tumors are deemed to be benign, by either imaging or biopsy, conservative observational management by serial MRI is acceptable. The scans will provide information on growth course, lymph node/vascular involvement, invasion of surrounding structures, and metastatic spread. The risks associated with observational management include progressive pain, neurologic dysfunction, and, rarely, malignant transformation.4Ball J.R. Biggs M.T. Operative steps in management of benign nerve sheath tumors.Neurosurg Focus. 2007; 22: E7Crossref PubMed Scopus (17) Google Scholar The patient under observation will require adequate pain control, physical therapy, and good follow-up. If a question of malignant transformation arises either initially or during follow-up, positron emission tomography can detect the increased metabolic rate consistent with malignancies.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google ScholarOf every 1 million people in the US, an average of 6 per year will require surgical intervention for peripheral nerve tumors.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google Scholar Currently, general indications for surgical management include severely symptomatic lesions with pain or neurologic deficit, malignant imaging findings, involvement of a major nerve plexus, or biopsy-confirmed malignancy.4Ball J.R. Biggs M.T. Operative steps in management of benign nerve sheath tumors.Neurosurg Focus. 2007; 22: E7Crossref PubMed Scopus (17) Google Scholar Post-operative adjuvant radiation therapy is indicated for marginally resected tumors; however, for the more common benign tumors, radiation is rarely required. The rare malignant tumors are candidates for postoperative radiation.3Perrin R.G. Guha A. Malignant peripheral nerve sheath tumors.Neurosurg Clin N Am. 2004; 15: 203-216Abstract Full Text Full Text PDF PubMed Scopus (71) Google Scholar, 5Dorsi M.J. Belzberg A.J. Paraspinal nerve sheath tumors.Neurosurg Clin N Am. 2004; 15 (vii): 217-222Abstract Full Text Full Text PDF PubMed Scopus (15) Google ScholarNeurofibromatosis can affect the rate of malignant transformation and subsequently dictate management options not only for the patient, but also quite possibly for the patient's family. Thus, if neurofibromatosis is suspected, a medical geneticist should be consulted sooner rather than later for further diagnostic and chromosomal evaluation.Orthopedic and neurologic surgery services both evaluated our patient for CT-guided biopsy and determined that it was unnecessary because the tumors did not involve the spinal cord, were not compromising neurologic function, and did not demonstrate malignant imaging findings. The pain resolved over the course of a few days with scheduled oral analgesics and inpatient physical therapy, and the patient was discharged with instructions for follow-up surveillance imaging. Outpatient genetic evaluation for neurofibromatosis was negative. The patient continues to do well with physical therapy. Currently, if a diagnosis of peripheral nerve sheath tumors is established either clinically (by imaging) or pathologically (by biopsy), 2 major management strategies exist: observation by serial imaging and surgical excision. Chemotherapy remains controversial and is usually considered only in malignant cases.3Perrin R.G. Guha A. Malignant peripheral nerve sheath tumors.Neurosurg Clin N Am. 2004; 15: 203-216Abstract Full Text Full Text PDF PubMed Scopus (71) Google Scholar Because the natural history of peripheral nerve sheath tumors is poorly understood, appropriate criteria for selection of a management option have yet to be established. More than 90% of peripheral nerve tumors are benign.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google Scholar No prospective studies exist, but current estimates place the incidence of malignant peripheral nerve sheath tumors at 0.001 % in the general population; this rate increases to 3-5 % in those with neurocutaneous syndromes.3Perrin R.G. Guha A. Malignant peripheral nerve sheath tumors.Neurosurg Clin N Am. 2004; 15: 203-216Abstract Full Text Full Text PDF PubMed Scopus (71) Google Scholar, 4Ball J.R. Biggs M.T. Operative steps in management of benign nerve sheath tumors.Neurosurg Focus. 2007; 22: E7Crossref PubMed Scopus (17) Google Scholar If the tumors are deemed to be benign, by either imaging or biopsy, conservative observational management by serial MRI is acceptable. The scans will provide information on growth course, lymph node/vascular involvement, invasion of surrounding structures, and metastatic spread. The risks associated with observational management include progressive pain, neurologic dysfunction, and, rarely, malignant transformation.4Ball J.R. Biggs M.T. Operative steps in management of benign nerve sheath tumors.Neurosurg Focus. 2007; 22: E7Crossref PubMed Scopus (17) Google Scholar The patient under observation will require adequate pain control, physical therapy, and good follow-up. If a question of malignant transformation arises either initially or during follow-up, positron emission tomography can detect the increased metabolic rate consistent with malignancies.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google Scholar Of every 1 million people in the US, an average of 6 per year will require surgical intervention for peripheral nerve tumors.1Singh T. Kliot M. Imaging of peripheral nerve tumors.Neurosurg Focus. 2007; 22: E6Crossref PubMed Scopus (37) Google Scholar Currently, general indications for surgical management include severely symptomatic lesions with pain or neurologic deficit, malignant imaging findings, involvement of a major nerve plexus, or biopsy-confirmed malignancy.4Ball J.R. Biggs M.T. Operative steps in management of benign nerve sheath tumors.Neurosurg Focus. 2007; 22: E7Crossref PubMed Scopus (17) Google Scholar Post-operative adjuvant radiation therapy is indicated for marginally resected tumors; however, for the more common benign tumors, radiation is rarely required. The rare malignant tumors are candidates for postoperative radiation.3Perrin R.G. Guha A. Malignant peripheral nerve sheath tumors.Neurosurg Clin N Am. 2004; 15: 203-216Abstract Full Text Full Text PDF PubMed Scopus (71) Google Scholar, 5Dorsi M.J. Belzberg A.J. Paraspinal nerve sheath tumors.Neurosurg Clin N Am. 2004; 15 (vii): 217-222Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar Neurofibromatosis can affect the rate of malignant transformation and subsequently dictate management options not only for the patient, but also quite possibly for the patient's family. Thus, if neurofibromatosis is suspected, a medical geneticist should be consulted sooner rather than later for further diagnostic and chromosomal evaluation. Orthopedic and neurologic surgery services both evaluated our patient for CT-guided biopsy and determined that it was unnecessary because the tumors did not involve the spinal cord, were not compromising neurologic function, and did not demonstrate malignant imaging findings. The pain resolved over the course of a few days with scheduled oral analgesics and inpatient physical therapy, and the patient was discharged with instructions for follow-up surveillance imaging. Outpatient genetic evaluation for neurofibromatosis was negative. The patient continues to do well with physical therapy.