Triton tumor of the left sympathetic nerve
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《血管的通路杂志》
Servicio de Cirugia Torácica. Hospital Universitario Reina Sofia, Avda. Menendez Pidal s/n. 14004 Cordoba. Spain
Abstract
Malignant triton tumor is a subtype of malignant peripheral nerve sheath tumor which presents a rabdomyoblastic differentiation. We report the case of a 14-year-old male with a radical surgical resection of a mediastinal malignant triton tumor of the sympathetic nerve, a rare location for this tumor. Thereafter, he received adjuvant radiotherapy and was reoperated three months later for an early local recurrence. The prognosis for this group of tumors is poor. Radical surgical excision of the tumor followed by radiation therapy must be the treatment of choice.
Key Words: Peripheral nerve sheath tumor; Malignant triton tumor; Mediastinum
1. Introduction
Malignant tumors with a peripheral nervous sheath are rare tumors derived from Schwann cells. They are associated with peripheral nerves and neurofibromatosis. Most of these tumors occur in patients with von Recklinhausen's disease, or as a late complication of irradiation, although there are also documented cases of sporadic occurrence. The ‘malignant triton tumor’ (MTT) is a variety of this type of tumors which presents a rhabdomyoblastic differentiation. This name is based on the particularity of the triton salamander, which can regenerate the striated muscle through the influence of the normal nerve. This type of tumor features a nervous, cartilaginous, and muscular-skeletal component.
2. Case report
The patient was a 14-year-old male, without signs of neurofibromatosis, who presented palpebral ptosis and miosis in the left eye for the previous three months. The physical examination revealed a unilateral Horner syndrome on the left side without muscular weakness. The routine laboratory data were normal. Under the suspicion of Miastenia gravis, the patient underwent a neurophysiological examination (Jitter) of the left frontal muscle, without finding disorders in the conduction. In addition, the determination of plasma levels of acetylcholine antibodies was normal and Miastenia gravis could be ruled out. A magnetic resonance imaging (MRI) of the orbit, cranium and supra-aortic trunks was performed without any finding that would justify Horner syndrome. A chest radiograph revealed the presence of a mediastinal mass. Chest computed tomography (CT) and magnetic resonance imaging (MRI) showed a round tumor in the superior paravertebral left mediastinum of 4 cm in diameter without communication with the spinal cord, in close relation with the supra-aortic left trunks, especially with the left vertebral artery which was surrounded by the tumor, and displaced anteriorly, as well as the left subclavian artery (Fig. 1). In the T1 sequence, the strength of the signal was medium, while in T2 and STIR it was high, but heterogeneous. In the T1 sequence, the tumor became hypointense with the suppresion of the fat (this suggested a clearly fatty component). These features suggested a cystic hygroma or a lymphangioma. On the basis of these findings, a surgical resection was proposed. A left posterolateral thoracotomy was carried out through the 4th intercostal space. A 5x4 cm left paraverterbral encapsulated tumor was found, originating on the sympathetic chain that did not have contact with the spinal cord. The tumor displaced the left subclavian artery and was fully resected (from T2 to the stallate-ganglion), along with wide margins of resection. The postoperative course was uneventful and the patient was discharged from hospital after five days. The Horner syndrome was not modified after surgery.
The pathologic examination of the specimen demonstrated the presence of a malignant tumor of the peripheral nervous sheath. It presented an S 100 positive phenotype, S 100 positive cartilaginous metaplasia, desmin positive and actin negative. It was diagnosed as a malignant triton tumor with neural, cartilaginous, and skeletal muscle differentiation. The resection margins were free of tumor. We applied adjuvant radiotherapy with a total dose of 3900 cGy. He was free of disease for only three months. A local recurrence was then observed in a subsequent chest CT scan. At rethoracotomy, the tumor involved the supraaortic vessels with cervical progression, precluding the complete resection of the tumor. A tumor reduction surgery was performed at this operative finding (Fig. 2).
3. Discussion
In 1932, Mason was the first one to describe rhabdomyoblasts in a peripheral-nerve tumor. The term ‘triton tumor’ was first described by Woodruff in 1973 [1]. It is an extremely rare tumor, with less than 100 cases documented world-wide, and less than 10 in the mediastinum [2,3]. Ours is the first case in the sympathetic nerve. This tumor may be associated with von Recklinghausen's disease. Approximately 69% of these tumors occur in these patients (young male), the remaining 31% being sporadic cases (older women) [4]. The MTT may affect adults and children, as the case reported herein, and presents chromosomal abnormalities (complete loss of a chromosome or some of its regions) [5]. Although it could be found anywhere (head, neck, trunk, and extremities) [2,3,6], the MTT has better prognosis in those localized in the extremities, presenting a worse prognosis than those that occur in the retroperitoneous and the trunk, with higher probabilities of local recurrence [7]. The tumor has a high propensity for early local recurrence, rather than metastatic disease. The prognosis is poor with a 5-year survival rate around 12% [4], and its location has been correlated with survival [8]. The treatment should include the complete resection of the tumor, as many times as necessary, including tumor reduction surgery followed by adjuvant radiotherapy to prevent local recurrence and metastases. Adjuvant chemotherapy has not been shown to be effective in this tumor [2–4].
In conclusion, the MTT is a rare tumor, especially when localized in the mediastinum. Our case is one of the few recorded in the specialized literature that is located in mediastinum, and the only one in the sympathetic nerve that has been reported. Despite the complete resection of the tumor followed by adjuvant radiotherapy, the natural history of disease was poor, with early local recurrence as a typical feature of this type of tumor.
References
Woodruff JM, Chernik NL, Smith MC, Millet WB, Foote FW. Peripheral nerve tumor with rhabdomyosarcomatous differentiation. Cancer 1973; 32:426–439.
Bose AK, Deodhar AP, Duncan AJ. Malignant triton tumor of the right vagus. Ann Thorac Surg 2002; 74:1227–1228.
Lang-Lazdunski L, Pons F, Jancovici R. Malignant ‘triton’ tumor of the posterior mediastinum: prolonged survival after staged resection. Ann Thorac Surg 2003; 75:1645–1648.
Brooks JS, Freeman M, Enterline HT. Malignant triton tumor. Cancer 1985; 55:2543–2549.
Bridge RS, Bridge JA, Neff JR, Naumann S, Althof P, Bruch LA. Recurrent chromosomal imbalances and structurally abnormal breakpoints within complex karyotypes of malignant peripheral nerve sheath tumor and malignant triton tumour: a cytogenetic and molecular cytogenetic study. J Clin Pathol 2004; 57:1172–1178.
Yilmaz MR, Bek S, Bekmezci T, Gkduman C, Solak AS. Malignant triton tumor of the lumbar spine. Spine 2004; 29:E399–E401.
Kostler WJ, Amann G, Grunt TW, Singer CF, Schneider SM, Brodowicz T, Tomek S, Zielinski CC. Recurrent malignant triton tumour: first report on a long time survivor. Oncol Rep 2003; 10:533–535.
Otani Y, Morishita Y, Yoshida I, Ishikawa S, Otaki A, Aihara T, Nakajima T. A malignant triton tumor in the anterior mediastinum requiring emergency surgery: report of a case. Surg Today 1996; 26:834–836.(Jose Ramon Cano, Francisc)
Abstract
Malignant triton tumor is a subtype of malignant peripheral nerve sheath tumor which presents a rabdomyoblastic differentiation. We report the case of a 14-year-old male with a radical surgical resection of a mediastinal malignant triton tumor of the sympathetic nerve, a rare location for this tumor. Thereafter, he received adjuvant radiotherapy and was reoperated three months later for an early local recurrence. The prognosis for this group of tumors is poor. Radical surgical excision of the tumor followed by radiation therapy must be the treatment of choice.
Key Words: Peripheral nerve sheath tumor; Malignant triton tumor; Mediastinum
1. Introduction
Malignant tumors with a peripheral nervous sheath are rare tumors derived from Schwann cells. They are associated with peripheral nerves and neurofibromatosis. Most of these tumors occur in patients with von Recklinhausen's disease, or as a late complication of irradiation, although there are also documented cases of sporadic occurrence. The ‘malignant triton tumor’ (MTT) is a variety of this type of tumors which presents a rhabdomyoblastic differentiation. This name is based on the particularity of the triton salamander, which can regenerate the striated muscle through the influence of the normal nerve. This type of tumor features a nervous, cartilaginous, and muscular-skeletal component.
2. Case report
The patient was a 14-year-old male, without signs of neurofibromatosis, who presented palpebral ptosis and miosis in the left eye for the previous three months. The physical examination revealed a unilateral Horner syndrome on the left side without muscular weakness. The routine laboratory data were normal. Under the suspicion of Miastenia gravis, the patient underwent a neurophysiological examination (Jitter) of the left frontal muscle, without finding disorders in the conduction. In addition, the determination of plasma levels of acetylcholine antibodies was normal and Miastenia gravis could be ruled out. A magnetic resonance imaging (MRI) of the orbit, cranium and supra-aortic trunks was performed without any finding that would justify Horner syndrome. A chest radiograph revealed the presence of a mediastinal mass. Chest computed tomography (CT) and magnetic resonance imaging (MRI) showed a round tumor in the superior paravertebral left mediastinum of 4 cm in diameter without communication with the spinal cord, in close relation with the supra-aortic left trunks, especially with the left vertebral artery which was surrounded by the tumor, and displaced anteriorly, as well as the left subclavian artery (Fig. 1). In the T1 sequence, the strength of the signal was medium, while in T2 and STIR it was high, but heterogeneous. In the T1 sequence, the tumor became hypointense with the suppresion of the fat (this suggested a clearly fatty component). These features suggested a cystic hygroma or a lymphangioma. On the basis of these findings, a surgical resection was proposed. A left posterolateral thoracotomy was carried out through the 4th intercostal space. A 5x4 cm left paraverterbral encapsulated tumor was found, originating on the sympathetic chain that did not have contact with the spinal cord. The tumor displaced the left subclavian artery and was fully resected (from T2 to the stallate-ganglion), along with wide margins of resection. The postoperative course was uneventful and the patient was discharged from hospital after five days. The Horner syndrome was not modified after surgery.
The pathologic examination of the specimen demonstrated the presence of a malignant tumor of the peripheral nervous sheath. It presented an S 100 positive phenotype, S 100 positive cartilaginous metaplasia, desmin positive and actin negative. It was diagnosed as a malignant triton tumor with neural, cartilaginous, and skeletal muscle differentiation. The resection margins were free of tumor. We applied adjuvant radiotherapy with a total dose of 3900 cGy. He was free of disease for only three months. A local recurrence was then observed in a subsequent chest CT scan. At rethoracotomy, the tumor involved the supraaortic vessels with cervical progression, precluding the complete resection of the tumor. A tumor reduction surgery was performed at this operative finding (Fig. 2).
3. Discussion
In 1932, Mason was the first one to describe rhabdomyoblasts in a peripheral-nerve tumor. The term ‘triton tumor’ was first described by Woodruff in 1973 [1]. It is an extremely rare tumor, with less than 100 cases documented world-wide, and less than 10 in the mediastinum [2,3]. Ours is the first case in the sympathetic nerve. This tumor may be associated with von Recklinghausen's disease. Approximately 69% of these tumors occur in these patients (young male), the remaining 31% being sporadic cases (older women) [4]. The MTT may affect adults and children, as the case reported herein, and presents chromosomal abnormalities (complete loss of a chromosome or some of its regions) [5]. Although it could be found anywhere (head, neck, trunk, and extremities) [2,3,6], the MTT has better prognosis in those localized in the extremities, presenting a worse prognosis than those that occur in the retroperitoneous and the trunk, with higher probabilities of local recurrence [7]. The tumor has a high propensity for early local recurrence, rather than metastatic disease. The prognosis is poor with a 5-year survival rate around 12% [4], and its location has been correlated with survival [8]. The treatment should include the complete resection of the tumor, as many times as necessary, including tumor reduction surgery followed by adjuvant radiotherapy to prevent local recurrence and metastases. Adjuvant chemotherapy has not been shown to be effective in this tumor [2–4].
In conclusion, the MTT is a rare tumor, especially when localized in the mediastinum. Our case is one of the few recorded in the specialized literature that is located in mediastinum, and the only one in the sympathetic nerve that has been reported. Despite the complete resection of the tumor followed by adjuvant radiotherapy, the natural history of disease was poor, with early local recurrence as a typical feature of this type of tumor.
References
Woodruff JM, Chernik NL, Smith MC, Millet WB, Foote FW. Peripheral nerve tumor with rhabdomyosarcomatous differentiation. Cancer 1973; 32:426–439.
Bose AK, Deodhar AP, Duncan AJ. Malignant triton tumor of the right vagus. Ann Thorac Surg 2002; 74:1227–1228.
Lang-Lazdunski L, Pons F, Jancovici R. Malignant ‘triton’ tumor of the posterior mediastinum: prolonged survival after staged resection. Ann Thorac Surg 2003; 75:1645–1648.
Brooks JS, Freeman M, Enterline HT. Malignant triton tumor. Cancer 1985; 55:2543–2549.
Bridge RS, Bridge JA, Neff JR, Naumann S, Althof P, Bruch LA. Recurrent chromosomal imbalances and structurally abnormal breakpoints within complex karyotypes of malignant peripheral nerve sheath tumor and malignant triton tumour: a cytogenetic and molecular cytogenetic study. J Clin Pathol 2004; 57:1172–1178.
Yilmaz MR, Bek S, Bekmezci T, Gkduman C, Solak AS. Malignant triton tumor of the lumbar spine. Spine 2004; 29:E399–E401.
Kostler WJ, Amann G, Grunt TW, Singer CF, Schneider SM, Brodowicz T, Tomek S, Zielinski CC. Recurrent malignant triton tumour: first report on a long time survivor. Oncol Rep 2003; 10:533–535.
Otani Y, Morishita Y, Yoshida I, Ishikawa S, Otaki A, Aihara T, Nakajima T. A malignant triton tumor in the anterior mediastinum requiring emergency surgery: report of a case. Surg Today 1996; 26:834–836.(Jose Ramon Cano, Francisc)