Analysis of clinical features and prognosis of malignant triton tumor: A report of two cases and literature review

Recurrent sporadic malignant triton tumor in the carotid sheath in the absence of neurofibromatosis

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.

Impact of CT and MRI in the diagnostic workup of malignant triton tumour-a monocentric analysis and review of the literature

OBJECTIVES

Malignant triton tumours (MTTs) are rare but aggressive subtypes of malignant peripheral nerve sheath tumours (MPNSTs) with a high recurrence rate and 5-year survival of 14%. Systematic imaging data on MTTs are scarce and mainly based on single case reports. Therefore, we aimed to identify typical CT and MRI features to improve early diagnosis rates of this uncommon entity.

METHODS

A systematic review on literature published until December 2022 on imaging characteristics of MTTs was performed. Based on that, we conducted a retrospective, monocentric analysis of patients with histopathologically proven MTTs from our department. Explorative data analysis was performed.

RESULTS

Initially, 29 studies on 34 patients (31.42 ± 22.6 years, 12 female) were evaluated: Literature described primary MTTs as huge, lobulated tumours (108 ± 99.3 mm) with central necrosis (56% [19/34]), low T1w (81% [17/21]), high T2w signal (90% [19/21]) and inhomogeneous enhancement on MRI (54% [7/13]). Analysis of 16 patients (48.9 ± 13.8 years; 9 female) from our institution revealed comparable results: primary MTTs showed large, lobulated masses (118 mm ± 64.9) with necrotic areas (92% [11/12]). MRI revealed low T1w (100% [7/7]), high T2w signal (100% [7/7]) and inhomogeneous enhancement (86% [6/7]). Local recurrences and soft-tissue metastases mimicked these features, while nonsoft-tissue metastases appeared unspecific.

CONCLUSIONS

MTTs show characteristic features on CT and MRI. However, these do not allow a reliable differentiation between MTTs and other MPNSTs based on imaging alone. Therefore, additional histopathological analysis is required.

ADVANCES IN KNOWLEDGE

This largest published systematic analysis on MTT imaging revealed typical but unspecific imaging features that do not allow a reliable, imaging-based differentiation between MTTs and other MPNSTs. Hence, additional histopathological analysis remains essential.

Surgical management of craniospinal axis malignant peripheral nerve sheath tumors: a single-institution experience and literature review

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.

Clinical diagnostic and radiographic features of recurrent intracranial malignant triton tumor in an adult: illustrative case

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.

Computed tomography imaging features of malignant 'triton' tumor to facilitate its clinical diagnosis: report of two cases

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.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12880-022-00848-9.

Liver metastasis 13 years after the resection of a malignant triton tumor originating in the duodenum

This is an additional case report of a malignant triton tumor arising in the duodenum that was removed by pancreatoduodenectomy. Liver and gallbladder dysfunctions were detected in a regular blood examination during a follow-up for hypertension in a 62-year-old woman with a previous surgical history for a malignant Triton tumor in the duodenum 13 years ago. Further examinations revealed a metastatic liver tumor originating from the malignant triton tumor in the duodenum. Since the progression of the liver tumor was detected after radiation therapy, complete resection was performed by right hepatectomy. Curative hepatectomy resulted in disease-free survival for 1 year and 5 months in an extremely rare case of liver metastasis derived from a malignant triton tumor in the duodenum.

Pseudoprogression of Malignant Peripheral Nerve Sheath Tumor in Patient with Neurofibromatosis Type 1, a Case Report

Pseudoprogression, defined as the radiographic false appearance of disease progression, is not frequently observed in patients with malignant peripheral nerve sheath tumor (MPNST). We report on a case of a patient with neurofibromatosis type 1 (NF1) MPNST pseudoprogression that presented as suspected local recurrence 9.5 years after last treatment. The patient underwent surgical resection following growth of a mass on sequential MRI imaging; surgical pathology, however, showed skeletal muscle with atrophy, fibroadipose tissue, and fat necrosis, without any evidence of tumor. As MPNST survival rates increase, physicians should consider pseudoprogression as a potential presentation after prior treatment.

Giant malignant Triton tumour of the posterior mediastinum

Outsized tumours of the mediastinum are always present a challenge for the thoracic surgeon. This is a case report of a giant malignant Triton tumour occupying almost the entire right hemithorax. The patient presented in the accident and emergency (A&E) with severe dyspnoea. He referred a history of surgically excised fibromyxomatous sarcoma of the left lower limb with 2 local recurrences. The imaging studies revealed apart the giant neoplasm, total right lung atelectasis and pleural effusion. After diagnostic evacuation of the pleural effusion and bronchoscopy, the patient operated through a right postero-lateral thoracotomy; a giant well-encapsulated tumour not invading any anatomic structures or lymph nodes originated from the posterior mediastinum was excised radically. The patient recovered well and received radiotherapy after the operation for preventing local recurrence.

Malignant triton tumor of the anterior mediastinum: a rare tumor in a rare location

Malignant triton tumors are an extremely aggressive form of malignant peripheral nerve sheath tumor that display rhabdomyosarcomatous features. While these tumors are extremely rare, they have a much higher incidence in patients with neurofibromatosis-1. We present a case of a 64-year-old male with neurofibromatosis-1 who presented to the hospital with sudden worsening of shortness of breath and dysphagia to solids. Radiological examination revealed a large mass in the anterior mediastinum causing significant narrowing and displacement of the upper trachea and esophagus. Biopsy of the mass, done by interventional radiology, demonstrated features of an MTT. The mass was subsequently resected but without confirmation of tumor-free margins and the patient underwent adjuvant radiation therapy. Repeat radiological examination approximately four months later revealed growing malignancy and new metastases, which eventually contributed to the patient's death seven months after his presentation to the hospital.

Malignant Glandular Triton Tumor Arising in the Radial Nerve with Prolonged Survival: A Case Report and Review of the Literature

Divergent differentiation is a well-known phenomenon in malignant peripheral nerve sheath tumors (MPNST) which occurs approximately in 15% of these tumors, usually towards mesenchymal elements. Differentiation towards epithelial components, however, is quite uncommon, and even exceptionally rare is concomitant mesenchymal and glandular differentiation. To our knowledge, only 14 cases of MPNST with both mesenchymal (rhabdomyoblastic) and glandular differentiation had been reported, and only two of these tumors had frankly malignant glandular components. Herein, we report the third such case. A 26-year-old male, without any of the stigmata of NF1, presented with a 2-year history of pain in his left shoulder and an elbow swelling of six-month duration. The tumor was initially diagnosed clinically as a neurofibroma at a local hospital. The patient underwent excision of the mass there, and pathological examination at that hospital showed the tumor to be MPNST. Six months later, the patient was referred to our hospital, a tertiary care medical center, with recurrent swelling at the same location. Histopathological material from the referral hospital was reviewed, and the tumor was diagnosed as MPNST with rhabdomyoblastic differentiation or malignant triton tumor (MTT) that contained in addition foci of malignant glandular epithelium. The patient refused any surgical intervention. He received three cycles of chemotherapy followed by radiotherapy with excellent response and marked reduction in the size of the tumor. The patient had prolonged survival for 10 years following the initial resection of the tumor.

Malignant triton tumour (MTT) of the lung with metastasis to the proximal femur

A 65-year-old female patient has a history of malignant triton tumour of the right upper lobe of the lung. She underwent right upper lobectomy and lymphadenectomy in May 2018. She presented in November 2019 with pathological fracture of the left proximal femur. It was not associated with neurofibromatosis. We decided to do an excisional biopsy of the mass and proximal femoral replacement followed by radiotherapy. Four months later, she presented with local recurrence. We organised a multidisciplinary team between the orthopaedic, histopathology and oncology teams. Then, we decided to treat her with chemotherapy. After 2 months of follow-up, she responded well to the chemotherapy with no further deterioration of her condition.

Intracranial Malignant Triton Tumor in Children: A Case Report

: 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 a mass shadow with slightly long T1 and long T2 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. CT and 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.

The importance of surgical margins in malignant Triton tumour of the trunk and extremities

Malignant Triton tumour (MTT) is a rare variant of malignant peripheral nerve sheath tumour with partial rhabdomyosarcomatous differentiation. To the best of our knowledge, the importance of the surgical resection margins on the outcome of patients with MTT is unknown. The present study is a retrospective review of 24 patients treated for MTT of the trunk and the extremities between 1997 and 2015 in two institutions. The association of surgical margins with overall and tumour recurrence-free survival was analysed. Furthermore, the typical morphological and immunohistochemical characteristics of the tumour were described. In patients treated with curative intent (17/24), a surgical margin exceeding 1 mm was significantly associated with better overall survival and local recurrence-free survival. The oncological outcome was however poor, with only 28% of patients surviving at 5 years. Histopathologically, necrosis was a common feature, and most tumours displayed focal positivity for S100 protein and focal or strong positivity for desmin. The present results highlight the aggressive behaviour of MTTs and underline the importance of adequate surgical treatment.

Neurofibromatosis-associated malignant peripheral nerve sheath tumors in children have a worse prognosis: A nationwide cohort study

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNST) are rare and aggressive non-rhabdomyoblastic soft-tissue sarcomas (NRSTS) in children. This study set out to investigate clinical presentation, treatment modalities, and factors associated with survival in pediatric MPNST using Dutch nationwide databases.

METHODS

Data were obtained from the Netherlands Cancer Registry (NCR) and the Dutch Pathology Database (PALGA) from 1989 to 2017. All primary MPNSTs were collected. Demographic differences were analyzed between adult and pediatric (age ≤18 years) MPNST. In children, demographic and treatment differences between neurofibromatosis type 1 (NF1) and non-NF1 were analyzed. A Cox proportional hazard model was constructed for localized pediatric MPNSTs.

RESULTS

A total of 70/784 MPNST patients were children (37.1% NF1). Children did not present differently from adults. In NF1 children, tumor size was more commonly large (> 5 cm, 92.3% vs 59.1%). Localized disease was primarily resected in 90.6%, and radiotherapy was administered in 37.5%. Non-NF1 children tended to receive chemotherapy more commonly (39.5% vs 26.9%). Overall, estimated five-year survival rates of localized NF1-MPNST was 52.4% (SE: 10.1%) compared with 75.8% (SE: 7.1%) in non-NF1 patients. The multivariate model showed worse survival in NF1 patients (HR: 2.98; 95% CI, 1.17-7.60, P = 0.02) and increased survival in patients diagnosed after 2005 (HR: 0.20; 95% CI, 0.06-0.69, P = 0.01). No treatment factors were independently associated with survival.

CONCLUSION

Pediatric MPNSTs have presentations similar to adult MPNSTs. In children, NF1 patients present with larger tumors, but are treated similarly to non-NF1 MPNSTs. In localized pediatric MPNST, NF1 is associated with worse survival. Promisingly, survival has increased for pediatric MPNSTs after 2005.

Malignant Triton Tumor in a Child: Case Report and Literature Review

Objective

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<0.05), postoperative chemotherapy/radiation therapy and patient prognosis (p<0.05).

Conclusion

The clinical and histopathological features and therapeutic options for MTT are discussed in the light of published data. Further studies are needed to improve survival in children with this rare malignant tumor.

Triton tumor of the orbit

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.

A nationwide cohort study on treatment and survival in patients with malignant peripheral nerve sheath tumours

BACKGROUND

Despite curative intents of treatment in localized malignant peripheral nerve sheath tumours (MPNSTs), prognosis remains poor. This study investigated survival and prognostic factors for overall survival in non-retroperitoneal and retroperitoneal MPNSTs in the Netherlands.

METHODS

Data were obtained from the Netherlands Cancer Registry and the Dutch Pathology Database. All primary MPNSTs were collected. Paediatric cases (age ≤18 years) and synchronous metastases were excluded from analyses. Separate Cox proportional hazard models were made for retroperitoneal and non-retroperitoneal MPNSTs.

RESULTS

A total of 629 localized adult MPNSTs (35 retroperitoneal cases, 5.5%) were included for analysis. In surgically resected patients (88.1%), radiotherapy and chemotherapy were administered in 44.2% and 6.7%, respectively. In retroperitoneal cases, significantly less radiotherapy and more chemotherapy were applied. In non-retroperitoneal MPNSTs, older age (60+), presence of NF1, size >5 cm, and deep-seated tumours were independently associated with worse survival. In retroperitoneal MPNSTs, male sex and age of 60+ years were independently associated with worse survival. Survival of R1 and that of R0 resections were similar for any location, whereas R2 resections were associated with worse outcomes. Radiotherapy and chemotherapy administrations were not associated with survival.

CONCLUSION

In localized MPNSTs, risk stratification for survival can be done using several patient- and tumour-specific characteristics. Resectability is the most important predictor for survival in MPNSTs. No difference is present between R1 and R0 resections in both retroperitoneal and non-retroperitoneal MPNSTs. The added value of radiotherapy and chemotherapy is unclear.

Recurrent epithelioid malignant peripheral nerve sheath tumor with neurofibromatosis type 1: A case report and literature review

Malignant peripheral nerve sheath tumors (MPNSTs) are unusual and aggressive malignant soft-tissue tumors that comprise 5-10% of all soft-tissue sarcomas. Approximately 50% of MPNST cases are associated with neurofibromatosis type-1 (NF-1). As a rare MPNST subset, the epithelioid variant of MPNST (eMPNST) is histologically characterized by the predominant presence of epithelioid tumor cells, and accounts for <5% of all MPNSTs. In addition, eMPNST is rarely associated with NF-1 when compared with conventional MPNST. Although extensive clinicopathological studies have been conducted on eMPNST, clinicians face difficulty when attempting to make an accurate diagnosis. Subsequently, the biological consequences, including recurrence, metastasis and mortality rate in patients with eMPNST remain unclear. The current study presents the case of a 71-year-old woman with eMPNST and a family history of NF-1 in whom tumors had recurred twice on the lower back. A literature search for eMPNSTs was conducted by browsing PubMed and MEDLINE for English-language articles, as well as references from review articles, and revealed 129 published cases. Only 5 cases of eMPNST were associated with NF-1. The studies were retrospectively reviewed and the clinicopathological data of the patients, including tumor site, treatment, follow-up, prognosis, and immunohistochemical positivity were collected.

Intradural extramedullary granular cell tumour in a cat

A 7-year-old domestic shorthair cat was evaluated for progressive paraparesis, inability to jump, a paralysed tail and inability to void the bladder. Neurologic examination was consistent with a L4-S3 localisation. Survey radiographs of the lumbar vertebral column revealed L4-L7 vertebral body remodelling. A pre-contrast T1-weighted hyperintense, diffusely enhancing intradural lesion extending from L4 to S1 vertebral bodies was detected by MRI. Large, mesenchymal, round-to-polygonal cells arranged in nests or sheets were found on histologic examination at post mortem. These cells were characterised by abundant intracytoplasmic PAS-positive, diastase-resistant granules and positive immunoexpression of vimentin, S-100, neuron-specific enolase and desmin. This is the first report of a spinal granular cell tumour in a cat.

Malignant triton tumor of the duodenum: report of a case

We report a case of malignant triton tumor of the duodenum, which is extremely rare. A submucosal malignant tumor was detected in the duodenum of a 49-year-old woman. The tumor was completely resected by performing pancreaticoduodenectomy. Pathological examination revealed that the lesion was a malignant peripheral nerve sheath tumor with rhabdomyoblastic differentiation, i.e., a malignant triton tumor. Long-term survival has been achieved with no recurrence at 8.5 years after surgery.