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Malignant peripheral nerve sheath tumor in the cervical spine with multiple nevus cell nevi
Journal of Orthopaedic Science 21 (2016) 250e254
Contents lists available at ScienceDirect
Journal of Orthopaedic Science journal homepage: http://www.elsevier.com/locate/jos
Case report
Malignant peripheral nerve sheath tumor in the cervical spine with multiple nevus cell nevi Kenichi Asano a, 1, Go Yoshida a, *, 1, Daigo Morita a, 1, Tadashi Ito a, 1, Yoji Shido b, Atsushi Kouyama a, 1, Toshiki Iwase a, 1, Yukihiro Matsuyama b a b
Department of Orthopaedic Surgery, Hamamatsu Medical Center, 328 Tomitsuka-cho, Naka-ku, Hamamatsu, Shizuoka 432-8580, Japan Department of Orthopaedic Surgery, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan
a r t i c l e i n f o Article history: Received 10 July 2014 Received in revised form 12 October 2014 Accepted 30 October 2014 Available online 2 July 2015
1. Introduction Malignant peripheral nerve sheath tumor (MPNST) is the diagnostic term for malignant neoplasms that arises from a peripheral nerve or that incurs nerve sheath differentiation [1,2]. Intra- and extradural MPNST in the upper cervical spine are extremely rare. Wide resection with a negative surgical margin is the most effective treatment [3,4]; however it is often not possible to achieve in cases of MPNST in the cervical spine because of the close proximity to vital structures such as the spinal cord and vertebral artery. We experienced a rare case of MPNST in the cervical spine with dermatological findings. The patient had distinctive multiple nevus cell nevi over his left upper extremity and trunk on the same side as the tumor. The patient underwent gross total resection of the tumor with postoperative radiotherapy, and there was significant neurological improvement after surgery. Therefore, we present the clinical and neurological manifestations, as well as the radiological and pathological findings, of an intra- and extradural cervical spinal MPNST with multiple nevus cell nevi.
* Corresponding author. E-mail address: [email protected] (G. Yoshida). 1 Tel.: þ81 053 453 7111; fax: þ81 053 452 9217.
2. Case report 2.1. Presentation The patient was a 45-year-old male from the Philippines with no medical history of neoplastic disease. He had more than a hundred black eruptions with the size ranging from 1 to 5 mm in diameter at the left side of his back and upper extremities (Fig. 1). Progressive posterior cervical pain and left hemiparesis was observed (manual muscle test 3/5). The patient was unable to walk by himself. He had severe bladder and bowel dysfunction. Magnetic resonance imaging (MRI) showed a dumbbell-shaped tumor spreading across the intra- and extradural space that was compressing the spinal cord medially at the C2-3 level. The tumor had an isointense signal on T1-weighted images, and a hyperintense signal on T2-weighted images. Gadolinium-enhanced MRI revealed heterogeneous enhancement in the tumor (Fig. 2). The lesion extended through the left C2-3 intervertebral foramen and compressed the left vertebral artery. 2.2. Surgery Under general anesthesia, the patient was placed in a prone position. Laminectomy was performed at C2-C3 levels. After a left C2-C3 facetectomy, the intradural tumor was detected ultrasonically. The tumor was easily isolated from the surrounding tissues. The intradural tumor was completely removed and duraplasty was performed. The left extradural tumor appeared adherent to the dura and C3 root, and we resected the tumor piece by piece after cutting the left C3 root (this root was not triggered by MEP). Cervical spine fixation was achieved using a pedicle screw and rod system. Pedicle screws were inserted bilaterally at C2-C3 levels (Fig. 3). 2.3. Pathologic study Hypercellular spindle cells were arranged in sweeping fascicles with a nuclear pleomorphism. Well differentiated areas showed irregularly buckled, wavy cells as typically observed in Schwann
http://dx.doi.org/10.1016/j.jos.2015.06.015 0949-2658/© 2015 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.
K. Asano et al. / Journal of Orthopaedic Science 21 (2016) 250e254
251
cells (Fig. 4a). After immunohistochemical staining, some tumor cells were positive for S-100 proteins (Fig. 4b), Leu-7 and GFAP. However, staining for Desmin, MyoD1, CD34, MelanA, HMB45, and CytokeratinAE1/AE3 showed negative results. Mitoses were frequent (10 per 1 high power fields) and necrosis was seen. The Ki67 index was approximately 58%. The histopathological findings of the tumor indicated an MPNST. In addition, pigmented eruptions histologically represented intradermal nevus (Fig. 5). 2.4. Postoperative course Postoperatively, the patient's neurological condition and posterior cervical pain were markedly improved. He was able to walk independently and to take care of himself. He underwent local irradiation, 2.0 Gy daily for 5 days a week. After a complete dose of 30 Gy, no adjuvant chemotherapy was performed. He returned home 3 months after surgery; however, he died because of thermic fever 1 year after surgery. There was no local recurrence or distal metastasis at that time. Consent for publication was obtained from the patient's families. 3. Discussion
Fig. 1. The patient had pigmented eruptions at the left side of his back.
MPNST has been classified as a soft tissue sarcoma and constitutes only 3%e10% of all soft tissue sarcomas [3,5]. The World Health Organization (WHO) coined the term “MPNST” to indicate that the lesions are malignant lesions of neurogenic origin with
Fig. 2. Preoperative magnetic resonance image showing the dumbbell-shaped C2-3 tumor with heterogeneous enhancement. (a)Sagittal gadolinium-enhanced image (b) Coronal gadolinium-enhanced image (c) Axial gadolinium-enhanced image.
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K. Asano et al. / Journal of Orthopaedic Science 21 (2016) 250e254
Fig. 3. Intraoperative photograph and Postoperative magnetic resonance image show that intra-to extradural tumor was removed and duraplasty was done. (a) Intraoperative photograph (b) Sagittal T2-weighted image (c) Coronal T2-weighted image (d) Axial T2-weighted image.
similar biological behavior [6]. MPNST can arise either de novo or from a sarcomatous degeneration within a pre-existing plexiform neurofibroma [5]. They have also been shown to arise within a field of previous irradiation [7,8]. A definitive diagnosis requires a biopsy specimen collected when the tumor is removed. Excision represents the mainstay of treatment, whereas the roles of
chemotherapy and radiotherapy are still being defined. Anghileri et al. (2006) [3] reported that a negative surgical margin is the most significant factor for survival and local control of MPNST. However, wide resection is often not possible to achieve in cases of spinal MPNST because of the close proximity to vital structures. MPNST in the upper cervical spine are extremely rare. Only 5 cases of MPNST
Fig. 4. Photomicrographs showing a hypercellular spindle cell population with some mitotic figures and nuclear pleomorphism. (a) Hematoxylin and eosin staining 400 (b) Some tumor cells immunoreactive for S-100 protein 400.
K. Asano et al. / Journal of Orthopaedic Science 21 (2016) 250e254
253
Fig. 5. Photomicrographs showing intradermal nevus. Nevus cells were identified beneath the basal layer of the epidermis. (a) Hematoxylin and eosin staining 1.25 (b) Hematoxylin and eosin staining 5 (c) Hematoxylin and eosin staining 20.
in the cervical spine have been previously reported [9e12] and, of these cases, wide resection was only achieved in 1 case, gross total resection in 2 cases and partial resection in 2 cases. In the present case, the tumor had developed across the intra- and extradural space, encasing the left vertebral artery. To perform a wide resection in such cases, vertebral artery embolization is usually required. However, because the balloon Matas test was positive, we realized that wide resection was difficult and we performed gross total resection of the tumor. The histology of MPNST is highly cellular, showing a fascicular pattern with spindle-shaped nuclei and scant cytoplasm. Diagnosis of gross fusiform tumors in relation to nerves include the microscopic features of spindle cells with a fascicular pattern and positive immunostaining for S-100 proteins and neuron specific enolase [13]. In the present case, the spindle cells were arranged in sweeping fascicles with pleomorphic nuclei. S-100 proteins were focal positive. Although clear cell sarcoma was still included in the differential diagnosis, we excluded it because the tumor was negative for HMB45 and MelanA. In addition, the tumor was negative for Desmin and MyoD1, thus, we excluded malignant Triton tumor. Finley and Kolbusz [14] reported a case of segmental neurofibromatosis with hyperpigmented speckles clinically appearing as a nevus spilus. Segmental neurofibromatosis (NF-5) -au-lait spots or neurofibromas, which is limited to a given had cafe segment of the body [15]. Segmental neurofibromatosis resembles our case, but we could not histologically find neurofibromas in pigmented eruptions. Nevus spilus comprise nevus cells in a junctional area and show diffuse junctional activity [16]. Our case was different from nevus spilus, and histologically represented intradermal nevus. In the present case, the patient had no medical and family his-au-lait spots or neurofibromas. Although we did not tory of cafe check the abnormality of NF1 gene, the tumor might be a sporadic neurofibrosarcoma not associated with NF1. On the other hand, he had multiple nevus cell nevi. Multiple nevus cell nevi were evident only on the left side of his back. Skin and nervous tissues were both derived from ectoderm. Therefore, it is possible for nevus cell nevi
to be associated with MPNST, and this is the only case of MPNST in the cervical spine with multiple nevus cell nevi. Lentiginous melanocytic nevus, such as melanocytic hyperplasia and lentigo simplex, are often associated with neurofibroma and its malignant counterpart, MPNST [17]. However, we have not found any report for the association of MPNST with multiple nevus cell nevi. It can be argued that the occurrence of this type of nevus in MPNST is a coincidence. Recent research indicates that skin melanocytes and Schwann cells are derived from the common population of the neural origin [18,19]. Nevus cells belong to the melanocyte lineage. The patient developed nevus cell nevi and MPNST on the same body segment. Thus, it is also suggested that the developmental anomaly of the common neural population leads to these skin lesions. A wide range of the gene analysis in nevus cells and MPNST cells of the patient will clarify this issue. In conclusion, we present a rare case of MPNST in the upper cervical spine with multiple nevus cell nevi. Gross tumor resection resolved both neurological and pain symptoms.
Conflict of interest The authors declare that they have no conflict of interest.
References [1] Wong WW, Hirose T, Scheithauer BW, Schild SE, Gunderson LL. Malignant peripheral nerve sheath tumor: analysis of treatment outcome. Int J Radiat Oncol Biol Phys 1998;42:351e60. [2] Louis DN, Ohgaki H, Wiestler OD, Cavenee WK, Burger PC, Jouvet A, Scheithauer BW, Kleihues P. The 2007 WHO classification of tumours of the central nervous system. Acta Neuropathol 2007;114:97e109. [3] Anghileri M, Miceli R, Fiore M, Mariani L, Ferrari A, Mussi C, Lozza L, Collini P, Olmi P, Casali PG, Pilotti S, Gronchi A. Malignant peripheral nerve sheath tumors: prognostic factors and survival in a series of patients treated at a single institution. Cancer 2006;107:1065e74. [4] Carli M, Ferrai A, Mattke A, Zanetti I, Casanova M, Bisogno G, Cecchetto G, Alaggio R, De Sio L, Koscielniak E, Sotti G, Treuner J. Pediatric malignant peripheral nerve sheath tumors: the Italian and German soft tissue sarcoma cooperative group. J Clin Oncol 2005;23:8422e30.
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[5] Angelov L, Davis A, O'Sullivan B, Bell R, Guha A. Neurogenic sarcomas:experience at the University of Toronto. Neurosurgery 1998;43:56e64. [6] Kar M, Deo SV, Shukla NK, Malik A, Dattagupta S, Mohanti BK, Thulkar S. Malignant peripheral nerve sheath tumors (MPNST)-clinicopathological study and treatment outcome of twenty-four cases. World J Surg Oncol 2006;4:55. [7] Baehring JM, Betensky RA, Batchelor TT. Malignant peripheral nerve sheath tumors: the clinical spectrum and outcome of treatment. Neurology 2003;61: 696e8. [8] Cashen DV, Parisien RC, Raskin K, Hornicek FJ, Gebhardt MC, Mankin HJ. Survival data for patients with malignant schwannoma. Clin Orthop Relat Res 2004;426:69e73. [9] Khan RJ, Asgher J, Sohail MT, Chughtai AS. Primary intraosseous malignant peripheral nerve sheath tumor: a case report and review of the literature. Pathology 1998;30:237e41. [10] Adamson DC, Cummings TJ, Friedman AH. Malignant peripheral nerve sheath tumor of the spine after radiation therapy for Hodgkin's lymphoma. Clin Neuropathol 2004;23:245e55. [11] Moon SJ, Lee JK, Seo BR, Kim JH, Kim SH, Lee KH, Lee MC. An intraosseous malignant peripheral nerve sheath tumor of the cervical spine: a case report and review of the literature. Spine 2008;33:712e6.
[12] Sasamori T, Hida K, Yano S, Aoyama T, Asano T, Kubota K, Ito M, Abumi K, Iwasaki Y, Saito H, Houkin K. Favorable outcome after radical resection and subsequent local irradiation of malignant peripheral nerve sheath tumor in the cervical spine: case report. Med Chir 2012;52:670e4. [13] Gachiani J, Kim DH, Nelson A, Kline D. Surgical management of malignant peripheral nerve sheath tumors. Neurosurg Focus 2007 Jun 15;22(6):E13. [14] Finley EM, Kolbusz RV. Segmental neurofibromatosis clinically appearing as a nevus spilus. Int J Dermatol 1993;32:358e60. [15] Riccardi VM. Neurofibromatosis: clinical heterogeneity. Curr Probl Cancer 1982;7:1e34. [16] Vaidya DC, Schwartz RA, Janniger CK. Nevus spilus. Cutis 2007;80:465e8. [17] Ball NJ, Kho GT. Melanocytic nevi are associated with neurofibromas in neurofibromatosis, type 1, but not sporadic neurofibromas: a study of 226 cases. J Cutan Pathol 2005;32:523e32. [18] Misago N. The relationship between melanocytes and peripheral nerve sheath cells (partⅠ): melanocytic nevus (excluding so-called “blue nevus”) with peripheral nerve sheath differentiation. Am J Dermatopathol 2000;22: 217e29. [19] Kroumpouzos G, Cohen LM. Intradermal melanocytic nevus with prominent Schwannian differentiation. Am J Dermatopathol 2002;24:39e42.
Contents lists available at ScienceDirect
Journal of Orthopaedic Science journal homepage: http://www.elsevier.com/locate/jos
Case report
Malignant peripheral nerve sheath tumor in the cervical spine with multiple nevus cell nevi Kenichi Asano a, 1, Go Yoshida a, *, 1, Daigo Morita a, 1, Tadashi Ito a, 1, Yoji Shido b, Atsushi Kouyama a, 1, Toshiki Iwase a, 1, Yukihiro Matsuyama b a b
Department of Orthopaedic Surgery, Hamamatsu Medical Center, 328 Tomitsuka-cho, Naka-ku, Hamamatsu, Shizuoka 432-8580, Japan Department of Orthopaedic Surgery, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan
a r t i c l e i n f o Article history: Received 10 July 2014 Received in revised form 12 October 2014 Accepted 30 October 2014 Available online 2 July 2015
1. Introduction Malignant peripheral nerve sheath tumor (MPNST) is the diagnostic term for malignant neoplasms that arises from a peripheral nerve or that incurs nerve sheath differentiation [1,2]. Intra- and extradural MPNST in the upper cervical spine are extremely rare. Wide resection with a negative surgical margin is the most effective treatment [3,4]; however it is often not possible to achieve in cases of MPNST in the cervical spine because of the close proximity to vital structures such as the spinal cord and vertebral artery. We experienced a rare case of MPNST in the cervical spine with dermatological findings. The patient had distinctive multiple nevus cell nevi over his left upper extremity and trunk on the same side as the tumor. The patient underwent gross total resection of the tumor with postoperative radiotherapy, and there was significant neurological improvement after surgery. Therefore, we present the clinical and neurological manifestations, as well as the radiological and pathological findings, of an intra- and extradural cervical spinal MPNST with multiple nevus cell nevi.
* Corresponding author. E-mail address: [email protected] (G. Yoshida). 1 Tel.: þ81 053 453 7111; fax: þ81 053 452 9217.
2. Case report 2.1. Presentation The patient was a 45-year-old male from the Philippines with no medical history of neoplastic disease. He had more than a hundred black eruptions with the size ranging from 1 to 5 mm in diameter at the left side of his back and upper extremities (Fig. 1). Progressive posterior cervical pain and left hemiparesis was observed (manual muscle test 3/5). The patient was unable to walk by himself. He had severe bladder and bowel dysfunction. Magnetic resonance imaging (MRI) showed a dumbbell-shaped tumor spreading across the intra- and extradural space that was compressing the spinal cord medially at the C2-3 level. The tumor had an isointense signal on T1-weighted images, and a hyperintense signal on T2-weighted images. Gadolinium-enhanced MRI revealed heterogeneous enhancement in the tumor (Fig. 2). The lesion extended through the left C2-3 intervertebral foramen and compressed the left vertebral artery. 2.2. Surgery Under general anesthesia, the patient was placed in a prone position. Laminectomy was performed at C2-C3 levels. After a left C2-C3 facetectomy, the intradural tumor was detected ultrasonically. The tumor was easily isolated from the surrounding tissues. The intradural tumor was completely removed and duraplasty was performed. The left extradural tumor appeared adherent to the dura and C3 root, and we resected the tumor piece by piece after cutting the left C3 root (this root was not triggered by MEP). Cervical spine fixation was achieved using a pedicle screw and rod system. Pedicle screws were inserted bilaterally at C2-C3 levels (Fig. 3). 2.3. Pathologic study Hypercellular spindle cells were arranged in sweeping fascicles with a nuclear pleomorphism. Well differentiated areas showed irregularly buckled, wavy cells as typically observed in Schwann
http://dx.doi.org/10.1016/j.jos.2015.06.015 0949-2658/© 2015 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.
K. Asano et al. / Journal of Orthopaedic Science 21 (2016) 250e254
251
cells (Fig. 4a). After immunohistochemical staining, some tumor cells were positive for S-100 proteins (Fig. 4b), Leu-7 and GFAP. However, staining for Desmin, MyoD1, CD34, MelanA, HMB45, and CytokeratinAE1/AE3 showed negative results. Mitoses were frequent (10 per 1 high power fields) and necrosis was seen. The Ki67 index was approximately 58%. The histopathological findings of the tumor indicated an MPNST. In addition, pigmented eruptions histologically represented intradermal nevus (Fig. 5). 2.4. Postoperative course Postoperatively, the patient's neurological condition and posterior cervical pain were markedly improved. He was able to walk independently and to take care of himself. He underwent local irradiation, 2.0 Gy daily for 5 days a week. After a complete dose of 30 Gy, no adjuvant chemotherapy was performed. He returned home 3 months after surgery; however, he died because of thermic fever 1 year after surgery. There was no local recurrence or distal metastasis at that time. Consent for publication was obtained from the patient's families. 3. Discussion
Fig. 1. The patient had pigmented eruptions at the left side of his back.
MPNST has been classified as a soft tissue sarcoma and constitutes only 3%e10% of all soft tissue sarcomas [3,5]. The World Health Organization (WHO) coined the term “MPNST” to indicate that the lesions are malignant lesions of neurogenic origin with
Fig. 2. Preoperative magnetic resonance image showing the dumbbell-shaped C2-3 tumor with heterogeneous enhancement. (a)Sagittal gadolinium-enhanced image (b) Coronal gadolinium-enhanced image (c) Axial gadolinium-enhanced image.
252
K. Asano et al. / Journal of Orthopaedic Science 21 (2016) 250e254
Fig. 3. Intraoperative photograph and Postoperative magnetic resonance image show that intra-to extradural tumor was removed and duraplasty was done. (a) Intraoperative photograph (b) Sagittal T2-weighted image (c) Coronal T2-weighted image (d) Axial T2-weighted image.
similar biological behavior [6]. MPNST can arise either de novo or from a sarcomatous degeneration within a pre-existing plexiform neurofibroma [5]. They have also been shown to arise within a field of previous irradiation [7,8]. A definitive diagnosis requires a biopsy specimen collected when the tumor is removed. Excision represents the mainstay of treatment, whereas the roles of
chemotherapy and radiotherapy are still being defined. Anghileri et al. (2006) [3] reported that a negative surgical margin is the most significant factor for survival and local control of MPNST. However, wide resection is often not possible to achieve in cases of spinal MPNST because of the close proximity to vital structures. MPNST in the upper cervical spine are extremely rare. Only 5 cases of MPNST
Fig. 4. Photomicrographs showing a hypercellular spindle cell population with some mitotic figures and nuclear pleomorphism. (a) Hematoxylin and eosin staining 400 (b) Some tumor cells immunoreactive for S-100 protein 400.
K. Asano et al. / Journal of Orthopaedic Science 21 (2016) 250e254
253
Fig. 5. Photomicrographs showing intradermal nevus. Nevus cells were identified beneath the basal layer of the epidermis. (a) Hematoxylin and eosin staining 1.25 (b) Hematoxylin and eosin staining 5 (c) Hematoxylin and eosin staining 20.
in the cervical spine have been previously reported [9e12] and, of these cases, wide resection was only achieved in 1 case, gross total resection in 2 cases and partial resection in 2 cases. In the present case, the tumor had developed across the intra- and extradural space, encasing the left vertebral artery. To perform a wide resection in such cases, vertebral artery embolization is usually required. However, because the balloon Matas test was positive, we realized that wide resection was difficult and we performed gross total resection of the tumor. The histology of MPNST is highly cellular, showing a fascicular pattern with spindle-shaped nuclei and scant cytoplasm. Diagnosis of gross fusiform tumors in relation to nerves include the microscopic features of spindle cells with a fascicular pattern and positive immunostaining for S-100 proteins and neuron specific enolase [13]. In the present case, the spindle cells were arranged in sweeping fascicles with pleomorphic nuclei. S-100 proteins were focal positive. Although clear cell sarcoma was still included in the differential diagnosis, we excluded it because the tumor was negative for HMB45 and MelanA. In addition, the tumor was negative for Desmin and MyoD1, thus, we excluded malignant Triton tumor. Finley and Kolbusz [14] reported a case of segmental neurofibromatosis with hyperpigmented speckles clinically appearing as a nevus spilus. Segmental neurofibromatosis (NF-5) -au-lait spots or neurofibromas, which is limited to a given had cafe segment of the body [15]. Segmental neurofibromatosis resembles our case, but we could not histologically find neurofibromas in pigmented eruptions. Nevus spilus comprise nevus cells in a junctional area and show diffuse junctional activity [16]. Our case was different from nevus spilus, and histologically represented intradermal nevus. In the present case, the patient had no medical and family his-au-lait spots or neurofibromas. Although we did not tory of cafe check the abnormality of NF1 gene, the tumor might be a sporadic neurofibrosarcoma not associated with NF1. On the other hand, he had multiple nevus cell nevi. Multiple nevus cell nevi were evident only on the left side of his back. Skin and nervous tissues were both derived from ectoderm. Therefore, it is possible for nevus cell nevi
to be associated with MPNST, and this is the only case of MPNST in the cervical spine with multiple nevus cell nevi. Lentiginous melanocytic nevus, such as melanocytic hyperplasia and lentigo simplex, are often associated with neurofibroma and its malignant counterpart, MPNST [17]. However, we have not found any report for the association of MPNST with multiple nevus cell nevi. It can be argued that the occurrence of this type of nevus in MPNST is a coincidence. Recent research indicates that skin melanocytes and Schwann cells are derived from the common population of the neural origin [18,19]. Nevus cells belong to the melanocyte lineage. The patient developed nevus cell nevi and MPNST on the same body segment. Thus, it is also suggested that the developmental anomaly of the common neural population leads to these skin lesions. A wide range of the gene analysis in nevus cells and MPNST cells of the patient will clarify this issue. In conclusion, we present a rare case of MPNST in the upper cervical spine with multiple nevus cell nevi. Gross tumor resection resolved both neurological and pain symptoms.
Conflict of interest The authors declare that they have no conflict of interest.
References [1] Wong WW, Hirose T, Scheithauer BW, Schild SE, Gunderson LL. Malignant peripheral nerve sheath tumor: analysis of treatment outcome. Int J Radiat Oncol Biol Phys 1998;42:351e60. [2] Louis DN, Ohgaki H, Wiestler OD, Cavenee WK, Burger PC, Jouvet A, Scheithauer BW, Kleihues P. The 2007 WHO classification of tumours of the central nervous system. Acta Neuropathol 2007;114:97e109. [3] Anghileri M, Miceli R, Fiore M, Mariani L, Ferrari A, Mussi C, Lozza L, Collini P, Olmi P, Casali PG, Pilotti S, Gronchi A. Malignant peripheral nerve sheath tumors: prognostic factors and survival in a series of patients treated at a single institution. Cancer 2006;107:1065e74. [4] Carli M, Ferrai A, Mattke A, Zanetti I, Casanova M, Bisogno G, Cecchetto G, Alaggio R, De Sio L, Koscielniak E, Sotti G, Treuner J. Pediatric malignant peripheral nerve sheath tumors: the Italian and German soft tissue sarcoma cooperative group. J Clin Oncol 2005;23:8422e30.
254
K. Asano et al. / Journal of Orthopaedic Science 21 (2016) 250e254
[5] Angelov L, Davis A, O'Sullivan B, Bell R, Guha A. Neurogenic sarcomas:experience at the University of Toronto. Neurosurgery 1998;43:56e64. [6] Kar M, Deo SV, Shukla NK, Malik A, Dattagupta S, Mohanti BK, Thulkar S. Malignant peripheral nerve sheath tumors (MPNST)-clinicopathological study and treatment outcome of twenty-four cases. World J Surg Oncol 2006;4:55. [7] Baehring JM, Betensky RA, Batchelor TT. Malignant peripheral nerve sheath tumors: the clinical spectrum and outcome of treatment. Neurology 2003;61: 696e8. [8] Cashen DV, Parisien RC, Raskin K, Hornicek FJ, Gebhardt MC, Mankin HJ. Survival data for patients with malignant schwannoma. Clin Orthop Relat Res 2004;426:69e73. [9] Khan RJ, Asgher J, Sohail MT, Chughtai AS. Primary intraosseous malignant peripheral nerve sheath tumor: a case report and review of the literature. Pathology 1998;30:237e41. [10] Adamson DC, Cummings TJ, Friedman AH. Malignant peripheral nerve sheath tumor of the spine after radiation therapy for Hodgkin's lymphoma. Clin Neuropathol 2004;23:245e55. [11] Moon SJ, Lee JK, Seo BR, Kim JH, Kim SH, Lee KH, Lee MC. An intraosseous malignant peripheral nerve sheath tumor of the cervical spine: a case report and review of the literature. Spine 2008;33:712e6.
[12] Sasamori T, Hida K, Yano S, Aoyama T, Asano T, Kubota K, Ito M, Abumi K, Iwasaki Y, Saito H, Houkin K. Favorable outcome after radical resection and subsequent local irradiation of malignant peripheral nerve sheath tumor in the cervical spine: case report. Med Chir 2012;52:670e4. [13] Gachiani J, Kim DH, Nelson A, Kline D. Surgical management of malignant peripheral nerve sheath tumors. Neurosurg Focus 2007 Jun 15;22(6):E13. [14] Finley EM, Kolbusz RV. Segmental neurofibromatosis clinically appearing as a nevus spilus. Int J Dermatol 1993;32:358e60. [15] Riccardi VM. Neurofibromatosis: clinical heterogeneity. Curr Probl Cancer 1982;7:1e34. [16] Vaidya DC, Schwartz RA, Janniger CK. Nevus spilus. Cutis 2007;80:465e8. [17] Ball NJ, Kho GT. Melanocytic nevi are associated with neurofibromas in neurofibromatosis, type 1, but not sporadic neurofibromas: a study of 226 cases. J Cutan Pathol 2005;32:523e32. [18] Misago N. The relationship between melanocytes and peripheral nerve sheath cells (partⅠ): melanocytic nevus (excluding so-called “blue nevus”) with peripheral nerve sheath differentiation. Am J Dermatopathol 2000;22: 217e29. [19] Kroumpouzos G, Cohen LM. Intradermal melanocytic nevus with prominent Schwannian differentiation. Am J Dermatopathol 2002;24:39e42.