Malignant triton tumor with thoracic region as the initial presentation: a case report.

Malignant Triton Tumor (MTT) of the neck

Malignant triton tumor (MTT) is a malignant peripheral nerve sheath tumor (MPNST) with rhabdomyoblastic differentiation. This rare tumor, with fewer than 100 cases reported in the literature, generally affects adult patients with neurofibromatosis 1 (NF-1). We report such a case in a 34-year-old man with NF-1 who presented with a mass over the medial side of the arm. Histopathologically finding of rhabdomyoblasts among malignant Schwann cells in a tumor arising from a peripheral nerve supported by immunostaining with S-100 protein and myogenin confirmed the diagnosis. MTT has a poor prognosis owing to its aggressive biological behavior. The fact that this tumor is extremely rare has prompted us to report this case.

Malignant Triton tumor (MTT) is a rare variant of Malignant Peripheral Nerve Sheath Tumors (MPNST) with striated muscle formation. The diagnosis of MTT must meet the diagnostic criteria of MPNST and proven rhabdomyoblast differentiation. This case is discussed because of its rare incidence, which is 5-10% of all MPNSTs. The prognosis in most MTT patients is poor due to its rarity. Malignant Triton tumor (MTT) is a rare variant of malignant peripheral nerve sheath tumor. A 34-year-old woman came to the Head and Neck Surgery clinic of RSUD Dr. Soetomo Surabaya with complaints of a lump on the left upper front neck. This painless lump was small, marble-sized, skin-colored, and had enlarged rapidly over the last year. On physical examination, a skin-colored mass was found in the anterior colli region sinistra, which extended to the infraauricula sinistra, measuring approximately 20 x 20 x 15 cm with a hard solid consistency, partially spongy, flat surface, and indistinct borders. The patient underwent wide excision, vascular exploration, and continued with radiotherapy. The prognosis in most MTT patients is poor, and due to its rarity, studies with a large number of cases are lacking. MTT is a rare variant of MPNST with rhabdomyoblastic differentiation that behaves more aggressively than typical MPNST, thus having a worse prognosis. Treatment modalities, especially in advanced and metastatic cases, still lack standardized management or guidelines for the management of MTT. Until now, surgical excision and adjuvant radiotherapy have been the main therapeutic options for MTT.

A 5-year-old girl with neurofibromatosis type 1 (NF1) presented with a 1-month history of progressive left hemiparesis. Brain MRI revealed a large extra-axial right frontal mass (figure 1). The pathologic findings after complete resection were compatible with malignant triton tumor (MTT) (figure 2). MTT is an aggressive subtype of malignant peripheral nerve sheath tumor, histopathologically characterized by a high-grade spindle cell tumor, with immunohistochemistry demonstrating reaction to skeletal muscle stains, such as desmin and myogenin.1,2 MTT is associated with NF1 in 38% of cases.1 Intracranial MTT is exceedingly rare, usually presenting radiologically as a rapidly enlarging, heterogeneous, and enhancing mass.2

Malignant triton tumors (MTTs) are malignant peripheral nerve sheath tumors with rhabdomyosarcomatous differentiation. Malignant triton tumors affecting the spine are rare but present special challenges to the neurosurgeon. The authors report on 2 new cases of spinal MTTs, and analyze the 8 previously reported cases found via database search. The patients include a 15-year-old girl with thoracic MTT, and a 24-year-old man with lumbosacral MTT; both patients underwent radical resection with spinal stabilization. When these cases were combined with the literature results there was a male/female ratio of 6:4, and an age range of 15-67 years (median 37.5). Nine patients presented with symptoms related to the spinal cord, cauda equina, or nerve root compression. Four patients had undergone previous radiotherapy, and 2 had neurofibromatosis Type 1. Five cases of MTT were lumbosacral, 4 were thoracic, and 1 was cervical. Seven patients had intradural extension of tumor. All patients underwent some form of surgery, with 8 having total macroscopic excision. However, 6 patients required subsequent operations. In the 8 patients for which survival data was available, median time from diagnosis to death was 12 months (range 3-16). Malignant triton tumors are rare but should be included in the differential diagnosis of spinal tumors, particularly in patients who have undergone previous radiotherapy or who have neurofibromatosis. The authors suggest roles for radical surgery and multidisciplinary management.

Malignant Triton Tumors (MTTs) are a rare and aggressive subtype of malignant peripheral nerve sheath tumors (MPNSTs), often associated with neurofibromatosis type 1. This case report describes a unique instance of recurrent sporadic MTT within the carotid sheath in a 33-year-old male without any personal or familial history of neurofibromatosis. The patient initially presented with a biopsy-confirmed MTT in the right neck, involving the carotid body and brachial plexus, and underwent partial resection, radiation therapy, and chemotherapy. Six months later, the patient presented with recurrent MTT, and subsequently underwent radical tumor resection, segmental right carotid artery resection, and deep femoral vein interposition. Recovery was complicated by hematoma formation, and the patient developed vocal fold paralysis and a left vocal fold cyst, necessitating further surgeries. Yearly follow-ups for 8years revealed no recurrence. This case emphasizes the importance of comprehensive patient evaluation, including clinical history, imaging, and biopsy findings, for accurate diagnosis and prompt surgical intervention in managing such rare and aggressive tumors. Further research is needed to identify novel therapies and improve survival rates for patients with MTTs.

Malignant peripheral nerve sheath tumor (MPNST) is an uncommon type of sarcoma that arises from peripheral nerve sheaths and rarely involves the spinal roots. The origin of this tumor is thought to be Schwann cells or pluripotent cells of the neural crest. The subgroup of tumors in which malignant Schwann cells coexist with malignant rhabdomyoblasts is termed malignant triton tumor (MTT). MPNSTs can show different degrees of malignancy, but overall spinal MTTs are high-grade lesions. We report the exceptional instance of a spinal low-grade MTT in a 39-year-old man treated with total surgical removal followed by local radiation therapy. Histological low grade was based on the lack of necrosis, a low grade of atypia, a low mitotic rate and a Ki-67 labelling index <25%. After 18 months of follow-up the patient is alive with no evidence of disease. A thorough review of the literature yielded 57 well-documented spinal MPNSTs. Ten of them corresponded to MTTs, but none showed low-grade features. An analysis of the clinical, radiological and treatment data was performed to identify factors that might influence the outcome. Overall the 18-month survival rate was 45% but dropped to 0% in the subgroup of spinal MTTs. Besides, a size exceeding 2 cm, extra-spinal extension, association with neurofibromatosis and subtotal removal were all related to a worse outcome. In conclusion, spinal MTTs generally exhibit a more aggressive behavior than conventional MPNSTs. The occurrence of a spinal low-grade MTT with a better prognosis should also be recognized.

We report the clinical course in a 25-year-old male patient of neurofibromatosis with malignant triton tumour (MTT). Triton tumour is a peripheral nerve sheath tumour with rhabdomyoblastic differentiation. This is relatively rare tumour of head and neck region and only 26 cases have been reported to date. The present case is the first reported MTT of parapharyngeal space, one of the most aggressive course among all head and neck MTTs, resulting in the death of the patient within three months following surgical resection. The aggressive nature of this tumour necessitates adjuvant therapeutic measures in addition to radical surgery in order to obtain better survival rates.

We report the fourth case of an intracranial malignant triton tumor not associated with a cranial nerve in a 26-year-old male with a clinical history of neurofibromatosis type 1. The patient was found unresponsive and displayed confusion, lethargy, hyperreflexia, and dysconjugate eye movements upon arrival at the emergency room. MRI revealed a large bifrontal mass. Biopsy demonstrated a high-grade spindle cell tumor with focal areas of rhabdomyoblasts that stained positive for desmin, myogenin, and muscle-specific actin. Electron microscopy showed skeletal muscle differentiation. Based on the clinical history of NF1 and the pathologic results, a diagnosis of malignant triton tumor was made. The differential diagnosis, immunohistochemistry, molecular genetics, and treatment of malignant triton tumor are reviewed.

Malignant triton tumor of cervical spine with hemorrhage

The authors present the clinical, radiological, pathological features, and autopsy findings of a patient with malignant triton tumor of the acoustic nerve, which probably arose from a pre-existing acoustic schwannoma. The term "malignant triton tumor" is applied to malignant schwannomas with rhabdomyoblastic differentiation. A cerebellopontine angle tumor with spinal drop metastasis occurred in this patient 10 months after near-total removal of the original tumor.

Late effects of therapy for Hodgkin's disease include secondary malignancies like leukemia, lymphoma or solid tumors developing after long periods of latency. Ionizing radiation often causes the last group. The highest risks have been described for induced breast and lung cancers. We are the first to report a malignant triton tumor (MTT) as a secondary malignancy after radiotherapy and chemotherapy for Hodgkin's lymphoma. MTT is a very rare subtype of malignant peripheral nerve sheath tumors with rhabdomyoblastic differentiation and an aggressive course of disease.

Malignant Triton Tumor of the Cervical Spine: Report of One Case and Review of the Literature

Malignant triton tumors (MTTs) are a rare and aggressive type of malignant peripheral nerve sheath tumor identified histologically by focal rhabdomyoblastic differentiation. A 37-year-old female with a prior history of Hodgkin lymphoma presented with acute-onset confusion, cognitive deficits, and weakness. Brain magnetic resonance imaging revealed a hemorrhagic intracranial mass later confirmed to be a malignant triton tumor. The patient underwent two resections and several courses of chemoradiation for multiple tumor recurrences and metastases. Unfortunately, despite extensive treatment, she died 2 years after initial presentation from complications of this tumor. Her overall survival (OS) of 26.7 months was double that reported in historical cohorts (OS ∼13 mos). The diagnosis and treatment of central nervous system MTTs are difficult and require a multidisciplinary team of neurosurgeons, radiologists, and oncologists. Histopathological analysis is required for confirmation of diagnosis. Gross-total resection of tumor and adjuvant radiation therapy have been shown to give patients the highest rates of survival and improved outcomes. Further studies and clinical trials are warranted to investigate the efficacy of chemotherapeutic agents like temozolomide, bevacizumab, and abemaciclib.

Malignant peripheral nerve sheath tumors (MPNST) are biologically aggressive spindle cell sarcomas with evidence of nerve sheath differentiation and/or arising from a peripheral nerve or neurofibroma. They show a marked tendency for local recurrence and metastasis. Approximately one half arise within patients with neurofibromatosis 1 (NF1), whereas the remainder is sporadic. Radioimaging studies are unreliable in differentiating MPNST from other sarcomas or from benign nerve sheath tumors. From the microscopic standpoint, the majority of MPNSTs are hypercellular, high grade spindle cell sarcomas with plentiful mitoses, often with some degree of nuclear pleomorphism and/or necrosis, and variable positivity for S100, SOX10, EMA, CD34, Nestin, GFAP, collagen IV, and p53 by immunohistochemistry. Approximately 15 % of all MPNSTs will exhibit some form of divergent differentiation, malignant triton tumor being the most frequent of these variants. Surgical excision with adequate margins is the mainstay of therapy.