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Background/Aim: Malignant triton tumor (MTT) is a rare, highly aggressive malignant nerve sheath tumor with rhabdomyoblastic differentiation. The overall 5-year survival rate is extremely low, and no standardized treatment exists. We report a case of MTT in the distal femur that was treated with surgery and chemotherapy. Case Report: A 16-year-old male was referred to our hospital due to severe pain during physical activity and difficulty in walking. He showed no café-au-lait spots and no family history of Neurofibromatosis-1. He underwent an incisional biopsy and was diagnosed with MTT of the distal femur. After administering preoperative chemotherapy using adriamycin, ifosfamide, and cisplatin, wide resection surgery was performed for MTT. Subsequently, postoperative chemotherapy using methotrexate, in addition to the agents mentioned above, was administered. One and a half years after the surgery, he can walk without pain, and there are no signs of local recurrence or metastasis. Conclusion: The combined modality treatment, integrating chemotherapy and surgery, has successfully prevented local recurrence and accomplished favorable outcomes without lung metastasis. [ABSTRACT FROM AUTHOR]

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 8 years 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. [ABSTRACT FROM AUTHOR]

A 28-year-old female, a known case of neurofibromatosis 1, presented to the respiratory medicine department with complaints of breathlessness and cough for 2 weeks’ duration. Clinical examination revealed right-sided moderate pleural effusion. Computed tomography (CT) chest revealed a large anterior mediastinal mass with chest wall infiltration. Histopathology showed neoplasm with epithelioid cells, arranged as sheets and interlacing spindle cells with a moderate amount of eosinophilic cytoplasm and inconspicuous nucleoli. Histopathological examination of excised specimen showed a malignant peripheral nerve sheath tumor with rhabdomyoblastic differentiation also known as malignant triton tumor. After palliative chemotherapy, later on follow-up, CT-guided biopsy from right side chest wall lesion also showed the same. Because of this rare presentation, we are reporting this case.

Malignant triton tumor (MTT) is a highly aggressive malignant neoplasm, classified as a variant of malignant peripheral nerve sheath tumor with rhabdomyoblastic differentiation. There are few reports that MTT occurred in urogenital system. In the present study, we report the first MTT occurring in the uterus. A 57‐year‐old woman came to the emergency department due to persistent vaginal bleeding for 2 months. The gynecological palpation found that a club‐shaped excrescence existed in the vagina about 7 cm × 3 cm × 3 cm. The mass located in the lower segment of the uterus and the cervix was confirmed by gynecological vaginal ultrasound and magnetic resonance imaging, which was preliminarily diagnosed as cervical carcinoma. After neoplasm punch biopsy, the pathological diagnosis was malignant triton tumor. The patient finally lost follow‐up. This is the first report about MTT in the uterus and suggests that pathological biopsy combined with imaging examination is necessary for the diagnosis of rarely MTT. [ABSTRACT FROM AUTHOR]

Abstract Background Malignant peripheral nerve sheath tumor (MPNST) is an exceedingly rare and aggressive tumor, with limited literature on its management. Herein, we present our series of surgically managed craniospinal MPNSTs, analyze their outcomes, and review the literature. Methods We retrospectively reviewed surgically managed primary craniospinal MPNSTs treated at our institution between January 2005 and May 2023. Patient demographics, tumor features, and treatment outcomes were assessed. Neurological function was quantified using the Frankel grade and Karnofsky performance scores. Descriptive statistics, rank-sum tests, and Kaplan–Meier survival analyses were performed. Results Eight patients satisfied the inclusion criteria (4 male, 4 female). The median age at presentation was 38 years (range 15–67). Most tumors were localized to the spine (75%), and 3 patients had neurofibromatosis type 1. The most common presenting symptoms were paresthesia (50%) and visual changes (13%). The median tumor size was 3 cm, and most tumors were oval-shaped (50%) with well-defined borders (75%). Six tumors were high grade (75%), and gross total resection was achieved in 5 patients, with subtotal resection in the remaining 3 patients. Postoperative radiotherapy and chemotherapy were performed in 6 (75%) and 4 (50%) cases, respectively. Local recurrence occurred in 5 (63%) cases, and distant metastases occurred in 2 (25%). The median overall survival was 26.7 months. Five (63%) patients died due to recurrence. Conclusions Primary craniospinal MPNSTs are rare and have an aggressive clinical course. Early diagnosis and treatment are essential for managing these tumors. In this single-center study with a small cohort, maximal resection, low-grade pathology, young age (

Background: Malignant peripheral nerve sheath tumor (MPNST) is an exceedingly rare and aggressive tumor, with limited literature on its management. Herein, we present our series of surgically managed craniospinal MPNSTs, analyze their outcomes, and review the literature. Methods: We retrospectively reviewed surgically managed primary craniospinal MPNSTs treated at our institution between January 2005 and May 2023. Patient demographics, tumor features, and treatment outcomes were assessed. Neurological function was quantified using the Frankel grade and Karnofsky performance scores. Descriptive statistics, rank-sum tests, and Kaplan–Meier survival analyses were performed. Results: Eight patients satisfied the inclusion criteria (4 male, 4 female). The median age at presentation was 38 years (range 15–67). Most tumors were localized to the spine (75%), and 3 patients had neurofibromatosis type 1. The most common presenting symptoms were paresthesia (50%) and visual changes (13%). The median tumor size was 3 cm, and most tumors were oval-shaped (50%) with well-defined borders (75%). Six tumors were high grade (75%), and gross total resection was achieved in 5 patients, with subtotal resection in the remaining 3 patients. Postoperative radiotherapy and chemotherapy were performed in 6 (75%) and 4 (50%) cases, respectively. Local recurrence occurred in 5 (63%) cases, and distant metastases occurred in 2 (25%). The median overall survival was 26.7 months. Five (63%) patients died due to recurrence. Conclusions: Primary craniospinal MPNSTs are rare and have an aggressive clinical course. Early diagnosis and treatment are essential for managing these tumors. In this single-center study with a small cohort, maximal resection, low-grade pathology, young age (< 30), and adjuvant radiotherapy were associated with improved survival. [ABSTRACT FROM AUTHOR]

Abstract Background Malignant ‘triton’ tumor is an extremely rare subtype of malignant periphery nerve sheath tumors. Clinical diagnosis of malignant triton tumor is difficult before surgery due to its low incidence and the lack of knowledge. Therefore, to describe and summarize the CT imaging characteristics of malignant triton tumor is of great assistance for early and preoperative diagnosis. Case presentation Two cases suspected of MTT by CT scan before operation were closely observed. The diagnosis of malignant triton tumor was eventually confirmed by immunochemical assay, which verified speculation of CT scans. Huge, irregular, well-circumscribed lobulated mass-like shadows can be observed from these patients by CT scans. Besides, heterogeneity of density within the body of tumor was well-established by CT scans, together with linear septum. Meanwhile, CT scans demonstrated that calcifications were remarkable at the margin of tumor body. Conclusions Some CT image features from two cases were presented as a reference for the preoperative consideration of MTT: (i) enormity of mass-like shadow; (ii) presence of well-circumscribed lobulated shape; (iii) septum within the well-defined mass accompanied with hemorrhage, necrosis and cystic changes as well as calcification, especially within neurofibromatosis type 1 patients.

The malignant peripheral nerve sheath tumor is one of the rare sarcomas that have a challenging diagnosis. It occurs independently with neurofibromatosis type 1. Some studies referred that malignant peripheral nerve sheath tumor attains a worse prognosis when it occurs in the head and neck region. In the reported case, a male patient with neurofibromatosis type 1 manifestations presented with a large mass in the temporal region. Based on the clinical history, histopathology, and immunohistochemical findings, the lesion was diagnosed as a low-grade malignant peripheral nerve sheath tumor with rhabdoid features. Surgical resection followed by intensity-modulated radiotherapy was the treatment of choice.

Background/aim: Malignant triton tumor (MTT) is a rare, highly aggressive malignant nerve sheath tumor with rhabdomyoblastic differentiation. The overall 5-year survival rate is extremely low, and no standardized treatment exists. We report a case of MTT in the distal femur that was treated with surgery and chemotherapy., Case Report: A 16-year-old male was referred to our hospital due to severe pain during physical activity and difficulty in walking. He showed no café-au-lait spots and no family history of Neurofibromatosis-1. He underwent an incisional biopsy and was diagnosed with MTT of the distal femur. After administering preoperative chemotherapy using adriamycin, ifosfamide, and cisplatin, wide resection surgery was performed for MTT. Subsequently, postoperative chemotherapy using methotrexate, in addition to the agents mentioned above, was administered. One and a half years after the surgery, he can walk without pain, and there are no signs of local recurrence or metastasis., Conclusion: The combined modality treatment, integrating chemotherapy and surgery, has successfully prevented local recurrence and accomplished favorable outcomes without lung metastasis., (Copyright © 2024, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Background: Malignant 'triton' tumor is an extremely rare subtype of malignant periphery nerve sheath tumors. Clinical diagnosis of malignant triton tumor is difficult before surgery due to its low incidence and the lack of knowledge. Therefore, to describe and summarize the CT imaging characteristics of malignant triton tumor is of great assistance for early and preoperative diagnosis. Case presentation: Two cases suspected of MTT by CT scan before operation were closely observed. The diagnosis of malignant triton tumor was eventually confirmed by immunochemical assay, which verified speculation of CT scans. Huge, irregular, well-circumscribed lobulated mass-like shadows can be observed from these patients by CT scans. Besides, heterogeneity of density within the body of tumor was well-established by CT scans, together with linear septum. Meanwhile, CT scans demonstrated that calcifications were remarkable at the margin of tumor body. Conclusions: Some CT image features from two cases were presented as a reference for the preoperative consideration of MTT: (i) enormity of mass-like shadow; (ii) presence of well-circumscribed lobulated shape; (iii) septum within the well-defined mass accompanied with hemorrhage, necrosis and cystic changes as well as calcification, especially within neurofibromatosis type 1 patients. [ABSTRACT FROM AUTHOR]

Abstract Background Soft tissue sarcomas affecting the root of an upper extremity raise the question of limb amputation depending on their location, size, and malignancy. Malignant triton tumors are a rare subtype of neurofibrosarcomas that have been poorly reported in the literature. We report the case of a challenging reconstruction of the upper extremity using a pedicled latissimus dorsal flap. Case presentation A 25-year-old Occidental man was referred to our sarcoma unit for the management of a large, high-grade malignant peripheral nerve sheath tumor with no regional or distant extension and very fast progression. He was treated first by concomitant neoadjuvant radiotherapy and chemotherapy. Carcinologic excision was performed “en bloc” including the skin, the tumor, and the flexor muscles of our patient’s elbow. Coverage of the skin defect and elbow flexion restoration were achieved by using a homolateral pedicled musculocutaneous latissimus dorsi flap. Histological analysis showed an R0 resection. The reconstruction process recovered a complete bending of his elbow. He is still in remission at 26 months follow-up. Conclusions A malignant triton tumor is a rare, aggressive, and high-grade sarcoma. It was successfully treated and this case report describes an effective treatment modality. Reconstructive surgery, allowing large, complete tumor removal, is indispensable after neoadjuvant chemotherapy and radiotherapy.

Malignant peripheral nerve sheath tumor (MPNST) is a very aggressive peripheral nerve sheath-derived sarcoma, which is one of the most difficult tumors to diagnose due to its wide spectrum of histological findings and lack of specific immunohistochemical markers. Recently, it has been reported that losses of expression of H3K27me3 and H3K27me2 caused by PRC2 dysfunction may be useful diagnostic markers for MPNST, but there is no consensus on their clinicopathological significance. Here, we investigated the relationship between loss of H3K27 methylation and various parameters and clarified the clinicopathological significance of such loss. We analyzed the clinicopathological and immunohistochemical features in 84 MPNST cases. Complete losses of H3K27me3 and H3K27me2 were observed in 37 (44%) and 29 (35%) cases, respectively. Losses of H3K27me3 and H3K27me2 were significantly correlated with myogenic immunopositivity (H3K27me3 vs. desmin, P = 0.0051; H3K27me3 vs. myogenin, P = 0.0009; H3K27me2 vs. myogenin, P = 0.042). Meanwhile, there were significant correlations between preservation of immunohistochemical neurogenic markers and intact H3K27me3 and H3K27me2 (H3K27me3 vs. S-100 protein, P = 0.0019; H3K27me3 vs. SOX10, P = 0.014; H3K27me2 vs. S-100 protein, P = 0.0011; H3K27me2 vs. SOX10, P = 0.0087). In multivariate analysis, local recurrence, distant metastasis, high FNCLCC grade, and loss of SOX10 expression were independent prognostic factors for overall survival. H3K27me3 and H3K27me2 expression was retained in all 26 cases of rhabdomyosarcoma non-alveolar subtype. In conclusion, we suggest that H3K27me3 and H3K27me2 immunonegativity is useful but not definitive for diagnosing MPNST. Complete loss of H3K27 methylation may be involved in aggressive transdifferentiation from neural differentiation to skeletal muscle differentiation in MPNST. [ABSTRACT FROM AUTHOR]

Abstract Under extreme conditions and in palliative settings, shared decision making with the patient is vital; narrative decisions beyond evidence could be considered. If there is a chance of symptom palliation, extended surgery should not be avoided merely because of the limited life expectancy.

Ailing Zhao,1–3,* Daling Ding,4,* Xueqin Li,1–3 Jiangtao Wang1–3 1Department of Infant Ward, Children’s Hospital Affiliated of Zhengzhou University, Zhengzhou, Henan 450018, People’s Republic of China; 2Department of Infant Ward, Henan Children’s Hospital, Zhengzhou, Henan 450018, People’s Republic of China; 3Department of Infant Ward, Zhengzhou Children’s Hospital, Zhengzhou, Henan 450018, People’s Republic of China; 4Department of Neurosurgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, People’s Republic of China*These authors contributed equally to this workCorrespondence: Jiangtao WangDepartment of Infant Ward, Children’s Hospital Affiliated of Zhengzhou University, Zhengzhou, Henan 450018, People’s Republic of ChinaEmail syd2004@yeah.netObjective: Malignant triton tumor (MTT) is a rare and devastating malignant peripheral nerve-sheath tumor, which shows rapid growth and poor clinical outcomes. Here, we reported a 2-year-old girl who was diagnosed as MTT, an overview of the literature was conducted to discuss the clinical features and optimal treatment strategies of MTT.Methods: We conducted an analysis of 42 patients from the PubMed, Medline, Embase and Web of Science databases for relevant articles published between 1938 and 2018.Results: A 2-year-old girl died of tumor recurrence. Forty-two eligible cases of MTT in children (birth to 18 years; mean age, 8.3 years), the highest frequency of occurrence was in 12–16 years; and the male-to-female ratio was 1.7:1. Only 33 provided complete treatment details: 11 patients received treatment by surgery alone; 2 received both surgery and chemotherapy; 4 received both surgery and radiation therapy; 14 received surgery, chemotherapy, and radiation therapy; 1 case received chemotherapy and radiation therapy; and only 1 received supportive care. In the 33 cases, the average OS and 5-year OS probability were 23.9 months (range, 0.3–156 months) and 27.5 ± 4.3%. There were significant differences between radiation therapy and patient survival (p

Malignant triton tumor (MTT) is a rare, aggressive type of tumor that commonly originates from mesenchymal tissue and is mainly found in adults. Herein, we report a single case of a 12-year-old boy diagnosed with intracranial MTT. This report presents the clinical features and imaging findings of MTT. The 12-year-old patient consulted the hospital due to intermittent dizziness and headache. Computed tomography (CT) showed low-density space-occupying lesion in the left parietal fossa. Magnetic resonance imaging(MRI) showed amass shadow with slightly long Tl and longT2 signal intensity in the same area. Contrast enhanced MRI (CE-MRI) showed obvious enhancement of the lesion. He was diagnosed with meningioma and underwent surgery. Postoperative histopathological examination diagnosed the lesion as MTT. Two months after the operation, CT examination showed tumor recurrence. He then underwent local radiotherapy and chemotherapy, and unfortunately, died six months later. Intracranial MTT should be considered as one of the differential diagnoses of intracranial meningiomas. CTand MRI are of great significance in the identification of lesion location, invasion range, and degree of malignancy. Final diagnosis of intracranial MTT requires histopathological examination. MTT has a poor prognosis, and surgical resection of the tumor is the preferred treatment. Intervention after early diagnosis is the key to improve the outcome of patients. [ABSTRACT FROM AUTHOR]

A triton tumor is a malignant peripheral nerve sheath tumor (MPNST) with rhabdomyomatous differentiation These tumors account for 5% of MPNSTs and have an extremely poor prognosis. We describe the case of a 14-year-old girl who presented with a history of painful, progressive protrusion of her right eye with a diminution of vision for the past five years. She had been diagnosed as having an embryonal rhabdomyosarcoma of the right orbit, and she had undergone surgical debulking followed by chemotherapy and radiotherapy. Despite undergoing multiple modalities of treatment, she had several recurrences prior to this consultation. We reviewed her histology slides. HPE features were consistent with a malignant triton tumor with cartilage and osseous differentiation. Immunohistochemistry was done to confirm the diagnosis. In view of the aggressive nature of the tumor with multiple recurrences; she was advised palliative radical excision to reduce the tumor burden. [ABSTRACT FROM AUTHOR]

• Malignant triton tumor are rare tumors causing ileus. • Multimodal treatment with repetitive surgical resection can improve outcome in MTT. • MTT shows a high rate of local recurrence. Malignant triton tumors (MTT) are rare but highly aggressive tumors that originate from the Schwann cells. These tumors can occur in any part of the body, mostly present late and carry poor prognosis. We present a 24-year-old man with a rectal MTT causing non-specific abdominal pain and recurring ileus. The MRI showed a rectal mass near the urinary bladder with compression on the seminal vesical. A complete surgical resection of the tumor was performed. The immunohistological report confirmed a rectal MTT. Because of persistent ileus during the post-operative palliative chemotherapy, another tumor debulking was performed. The patient died 9 months after the diagnosis of MTT due to local recurrence under chemotherapy. MTTs are uncommon tumors in young age with high morbidity and mortality because of local recurrence also after complete resection. [ABSTRACT FROM AUTHOR]

Background: Soft tissue sarcomas affecting the root of an upper extremity raise the question of limb amputation depending on their location, size, and malignancy. Malignant triton tumors are a rare subtype of neurofibrosarcomas that have been poorly reported in the literature. We report the case of a challenging reconstruction of the upper extremity using a pedicled latissimus dorsal flap.Case Presentation: A 25-year-old Occidental man was referred to our sarcoma unit for the management of a large, high-grade malignant peripheral nerve sheath tumor with no regional or distant extension and very fast progression. He was treated first by concomitant neoadjuvant radiotherapy and chemotherapy. Carcinologic excision was performed "en bloc" including the skin, the tumor, and the flexor muscles of our patient's elbow. Coverage of the skin defect and elbow flexion restoration were achieved by using a homolateral pedicled musculocutaneous latissimus dorsi flap. Histological analysis showed an R0 resection. The reconstruction process recovered a complete bending of his elbow. He is still in remission at 26 months follow-up.Conclusions: A malignant triton tumor is a rare, aggressive, and high-grade sarcoma. It was successfully treated and this case report describes an effective treatment modality. Reconstructive surgery, allowing large, complete tumor removal, is indispensable after neoadjuvant chemotherapy and radiotherapy. [ABSTRACT FROM AUTHOR]

Malignant triton tumor (MTT) is a rare subtype of malignant peripheral nerve sheath tumors (MPNSTs) histologically defined by rhabdomyoblastic differentiation. MTTs are primarily found in the head, neck, extremities and trunk, but rare cases of MTT within the buttock, the mediastinum and the retroperitoneum have also been documented. We present the case of a 47-year-old male patient who initially presented with right flank pain and hematuria in July 2019, who was found to have a large pelvic mass below peritoneal reflection. Complete resection of the mass was performed, and pathology identified the mass as a MTT. [ABSTRACT FROM AUTHOR]

• Malignant triton tumor (MTT) is extremely rare subset of malignant peripheral nerve sheath tumor (MPNST) which accounts for < 10% of all MPNST. • Due to their aggressive biological behavior prognosis is very poor. • To date in medical literature only 12 cases of malignant triton tumor has been reported. • We report series of three mediastinal malignant triton. • Managed with radical surgical resection and neoadjuvent chemotherapy &radiotherapy. In 1938, the Malignant Triton Tumor (MTT) was first explained by Mason. Case 1: A man aged 28 years presented with chest pain and difficulty in breathing since last five months, there was no history of cough fever or night sweats. Clinical examination was unremarkable. His routine hematological tests including tumor markers were within normal range, testicular ultrasound was normal. CT scan of thorax revealed a mass in the anterior mediastinum. CT guided biopsy revealed a malignant triton tumor. Case 2: A 30 years old man, nonsmoker presented with history of chest tightness and feeling pressure while kneeling down since last 3 months, otherwise fit and healthy. His routine hematological investigations including tumor markers were within normal range. A CT scan of thorax revealed a large mass in the right posterior mediastinum. CT guided biopsy showed malignant triton tumor. Case 3: A man aged 28 years presented with chest pain and difficulty in breathing since last five months, there was no history of cough fever or night sweats. Clinical examination was unremarkable. His routine hematological tests including tumor markers were within normal range, testicular ultrasound was normal. CT scan of thorax revealed a mass in the anterior mediastinum. CT guided biopsy revealed a malignant triton tumor. Malignant peripheral nerve sheath tumors (MPNST) are uncommon sarcomatous tumors that are believed to be derived from Schwann cell or neighboring cells with perineurial differentiation. MTT is rarely reported in mediastinum, lung and heart (<10%) To the best of our knowledge, only few cases of MTT in the mediastinum have been reported in English literature, including, four were reported in the anterior mediastinum, three in the posterior mediastinum, one in the middle mediastinum and one between the ascending aorta and the main pulmonary artery. Most of the patients were young adults. We report three cases of rare mediastinal malignant triton tumors. They have been treated with palliative surgery/radical surgery +/− adjuvant therapy. The prognosis varied from a 3 month overall survival time to being alive at a 53 month follow-up period. In conclusion we report three rare cases of mediastinal malignant triton tumor treated with radical surgical resection and post-operative radiotherapy, one patient developed lung metastasis, and two had late local recurrence. The malignant triton tumor is a lethal neoplasm which carries very poor prognosis particularly when they occur in the mediastinum because it's very difficult to obtain wider tumor free margin due to the nature of location site. [ABSTRACT FROM AUTHOR]

Introduction: We report a rare and aggressive case of malignant triton tumor (MTT) at the thoracolumbar junction with foraminal extension mistreated as schwannoma.Materials and Methods: A 70-year-old man with a 2-year history of lower back pain and left L4 radiculopathy with no history of neurofibromatosis.Results: Pre-operative MRI suggested a typical schwannoma. Upon complete marginal resection, histological findings revealed a MTT. The patient presented with a local and regional recurrence and died 10 months after surgery. MTTs are a subgroup of malignant peripheral nerve sheath tumors, which develop from Schwann cells of peripheral nerves or within existing neurofibromas, and display rhabdomyoblastic differentiation.Conclusion: Based on the Grand Round case and relevant literature, we present a case of a highly aggressive and fast-growing tumor with a very high local and distant recurrence. There is no consensus treatment plan available and patients usually die shortly after diagnosis. [ABSTRACT FROM AUTHOR]

Malignant triton tumor (MTT) is a highly aggressive malignant neoplasm, classified as a variant of malignant peripheral nerve sheath tumor with rhabdomyoblastic differentiation. MTT is rarely reported in children, and its true prevalence may be underestimated. We herein report such a case in an 8-year-old boy who presented with a mass over the trapezius muscle. He was previously diagnosed with neurofibromatosis in the same area. Four years later, a follow-up magnetic resonance imaging revealed an intradural tumor recurrence at the level of C1–C7. An immunohistochemical test result was positive for S-100 protein and desmin, which confirmed the diagnosis. The patient outcome was fatal despite multimodal therapy. The possibility of this rare but devastating tumor must always be considered when patients present with new compressive spinal symptoms.

Malignant peripheral nerve sheath tumor (MPNST) is a rare form of sarcoma arising from Schwann cells or pluripotent cells of the neural crest. Malignant triton tumor (MTT) is a subtype of MPNST with a component of malignant rhabdomyoblasts in addition to malignant Schwann cells. MPNST and MTT are both aggressive malignancies that most commonly arise from large deep neurofibromas in patients with neurofibromatosis type 1 (NF-1). However, sporadic non-NF-1 cases of MTT have also been reported in the literature. We present a case of a 50-year-old African American male with no stigmata of NF-1 who developed a large mass in a free flap on the right calf. The free flap had been placed by plastic surgery 15 years previously following open right tibial and fibular fractures associated with a large soft tissue defect. Biopsy of the enlarging mass, followed by wide surgical excision, confirmed the pathology to be MTT. Although the development of a high-grade soft tissue sarcoma has been previously reported as a late complication of radiation therapy following free flap reconstructions, we believe this is the first reported case of sarcomatous transformation arising in a vascularized, free muscle transfer. [ABSTRACT FROM AUTHOR]

A 20-year-old Haflinger gelding was submitted with a history of neoplasms as big as a child's head located craniomedial at both thighs. Due to the morphology and predilection sites, initially there was the clinical suspicion of equine sarcoids. Because of advanced tumor growth the treatment consisted in surgical excision under general anesthesia. In the present case representative sites of neoplasia were embedded in paraplast and then asessed by light microscope at the H.-E.-stained cut. In the course of histological examination after routine processing multiple neoplasms composing the clinical visible proliferation medial on the right tight could be identified. In this patient, among other things, a tissue formation was diagnosed, whose histomorphology appeared similar to malignant Triton tumors in humans. These kind of neoplasia are very fast-growing, malignant nerve sheath tumors of peripheral nerves with rhabdomyoblastic differentiation. An immunohistological characterization was done to exclude other mesenchymal tumors (e.g. rhabdomyosarcoma or ulcerated equine sarcoid). The neoplastic cells were checked on a possible expression of S-100-protein, glial fibrillary acidic protein, (GFAP) and desmin. Both, the spindle and the rhabdomyoblastic tumor cells, showed an moderate to high-grade intracytoplasmic expression of S-100-protein. However, an expression of Desmin and GFAP could not be evidenced. The immunohistological result confirmed the suspected diagnosis of a malignant peripheral nerve sheath tumor with rhabdomyoblastic differentiation. To the authors knowledge this is the first description of such a Triton tumor in the horse. So far, there is no data regarding the specific therapy and prognosis in this species. The treatment included surgical excision and subsequent adjuvant therapy with autogenous vaccines. In a period of two years no recurrence in the case has been observed. [ABSTRACT FROM AUTHOR]

Background: Malignant triton tumors (MTTs) are a rare and aggressive type of malignant peripheral nerve sheath tumor identified histologically by focal rhabdomyoblastic differentiation., Observations: 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)., Lessons: 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) constitute a rare variety of soft tissue sarcomas thought to originate from Schwann cells or pluripotent cells of the neural crest. Malignant triton tumor (MTT), a very rare, highly aggressive soft tissue tumor, is a subgroup of MPNST and is comprised of malignant Schwann cells coexisting with malignant rhabdomyoblasts. We herein report the case of a 24-year-old man who presented a subcutaneous mass in his right thigh. The mass was removed surgically in its entirety and radiation therapy was applied locally to prevent tumor regrowth. Nonetheless, the patient died 10 months after surgery from metastases to the lung and brain. He presented neither cafe-au-lait spots nor cutaneous neurofibromas. The histopathology showed a transition from a neurofibroma to an MTT, making this the second report of an MTT arising from a neurofibroma without neurofibromatosis type 1, an autosomal dominant disorder with which 50-70% of tumors reported in previous studies were associated. A histopathological examination using immunostaining with desmin confirmed this diagnosis. MTT has a poorer prognosis than MPNST and should therefore be regarded as a distinct clinical entity.

Malignant peripheral nerve sheath tumor with rhabdomyoblastic differentiation, malignant triton tumor, has a rare incidence. We report such a case in a 40-year-old male who presented with a mass over the buttock. He was a previously diagnosed case of neurofibroma in the same area. Histomorphology supported by immunostaining with S-100 protein confirmed the diagnosis. Malignant triton tumor has a poor prognosis owing to its aggressive biological behavior. The fact that the presence of this tumor in the buttock region is extremely rare has prompted the authors to report this case.

Introduction:Malignant peripheral nerve sheath tumors (MPNSTs) are very rare. Malignant triton tumor is an aggressive variety of MPNSTs with rhabdomyoblastic differentiation. In this study we reported the clinical, radiographic, histopathologic and immunohistochemical features of an intramandibular malignant triton tumor. Case Report: The patient was a 31 year-old male who was referred to maxillofacial surgery ward of Mashhad dental school with a painful swelling in the anterior part of mandible and facial asymmetry. After histopathological evaluation, surgery was performed and immunohistochemical staining confirmed the diagnosis of Triton tumor. Patient was referred for further necessary treatments. Conclusion: In cases of mandibular tumors with initial histopathologic findings of sarcoma, uncommon differential diagnosis such as peripheral nerve sheath tumors must be considered as well.

A 15-year-old female was previously admitted to another hospital because of painless swelling of the lateral right nasal ala for 2 months. Magnetic resonance imaging revealed an expansive enhancing lesion in close proximity to the anterior surface of the right maxillary sinus and lateral wall of the right nasal cavity. Tumor extirpation was performed via the supragingival transantral approach under general anesthesia. Histopathological study revealed a malignant triton tumor (MTT) arising from the nasal vestibule. The patient was referred to our department for consultation regarding additional treatment. Because the surgical margin was positive and MTT has high malignant potential, we recommended expansion re-surgical treatment following immediate free-flap reconstruction and postoperative radiotherapy, but family consent was not obtained. Tumor regrowth was noted 1 month after her first visit to our department. The patient and her family accepted radiotherapy instead of surgical treatment. Complete remission was achieved by radiotherapy alone. No local recurrence or distant metastasis was observed for 30 months after radiotherapy. The conventional mode of treatment for MTT is radical excision followed by high-dose radiotherapy. However, this case is remarkable because our patient experienced complete remission by simple radiotherapy. [ABSTRACT FROM AUTHOR]

Background Malignant triton tumors (MTT) represent a rare subset of tumors with rhabdomyoblastic differentiation within the heterogeneous group of malignant peripheral nerve sheath tumors (MPNST). Case presentation Here, we report on a case of a 25 year-old male with a history of neurofibromatosis type I and MTT of the mediastinal wall who presented in our clinic with a pelvic tumor and multiple hypervascular mesenteric masses and underwent resection. Upon resection, histological findings revealed an MTT of the omentum and an atypical neurofibroma of the pelvis with focal transitions to a low-grade MPNST. The patient relapsed just one month later and died 3 months after the surgery. Conclusion Clinically, MTTs are characterized as highly aggressive tumors that are fast-growing and prone to local recurrence and distant metastasis. To date, there is no treatment consensus available yet and many patients succumb to the disease shortly after diagnosis. This is because the pathogenesis of MTT remains unknown and patients with MTT are often diagnosed at a late stage of disease. Our case presents valuable teaching points in terms of providing a possible progression model based on the coexistence of a low-grade MPNST and MTT in the context of NF1 and an atypical neurofibroma in this patient. Close monitoring of patients with NF1 and atypical neurofibromas or MPNST might therefore help to diagnose MTT at an earlier stage. [ABSTRACT FROM AUTHOR]