Malignant triton tumour of the thigh—A retrospective analysis of nine cases

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.

Malignant triton tumor of the kidney in a child: A case report

Introduction

Malignant triton tumor (MTT) is an extremely rare variant of the malignant peripheral nerve sheath tumors (MPNSTs) with rhabdomyosarcomatous differentiation, which was first described in 1932 by Mason. MTT affects, in most cases, patients under 35 years of age, and it is usually manifested as a mass that may or not be painful. However, the incidence in pediatric patients is atypical. This tumor presents an aggressive course and limited survival rate, and the prognosis is different between individuals with or without a concomitant diagnosis of neurofibromatosis type 1 (NF1). Currently, the recommended treatment is surgical resection, and adjuvant chemotherapy and radiotherapy, but its efficacy is not yet clear.

Presentation of the case

A 13-year-old female patient was referred to the pediatric oncology service due to the presence of an abdominal mass and weight loss, initially diagnosed with Wilms' tumor. After extensive investigation, surgical resection, and immunohistopathological evaluation, the diagnosis of malignant triton tumor was confirmed. The patient also underwent cycles of chemotherapy after resection, and is currently awaiting immunotherapy.

Discussion and conclusion

Malignant triton tumor is extremely rare and difficult to diagnose, especially in children or young people, age groups in which the incidence of the disease is even lower. This may be the reason it is rarely suspected, and it was a great challenge for the clinical care team. It is essential to consider and investigate this possibility of differential diagnosis, as patients diagnosed with this malignant tumor have a low survival rate and poor prognosis.

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Malignant triton tumor (MTT) is an extremely rare histological subtype of MPNSTs.

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MTT is an MPNST with rhabdomyosarcomatous differentiation.

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MTT is an extremely rare type of neoplasia, especially in pediatric patients.

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The kidney is an uncommon growth site of MTT.

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MTT presents a complex anatomopathological and immunohistochemical diagnosis.

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.

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.

Retroperitoneal malignant triton tumor in an infant: a case report and literature review

Malignant triton tumor (MTT) is a rare subtype of malignant peripheral nerve sheath tumor (MPNST) with rhabdomyoblastic differentiation. MTTs are solid tumors commonly located in the head, neck, extremities, and trunk. The presence of this tumor in an infant's retroperitoneum is extremely rare, and prompted the authors to report this case with reference to existing literature.

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.

Low-grade malignant triton tumor of the neck: a case report and review of the literature

Rhabdomyoblastic differentiation in a malignant peripheral nerve sheath tumor (MPNST) is termed malignant triton tumor (MTT), a rare neoplasm that poses a diagnostic dilemma in the differential diagnosis of neck masses and portends poor prognosis. We report a sporadic case of MTT of the neck in a 23-year-old female. We present the pathological findings. Immunohistochemistry confirmed the neurogenic origin with S-100 expression and the rhabdomyoblastic differentiation with desmin and vimentin positivity. Radical surgical excision was done. After 4 years there were no signs of recurrence or distant metastasis. The clinical, microscopic, and long-term follow-up of this case are consistent with those of a low-grade malignancy.

Malignant triton tumor: a rare case

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.

A Rare Malignant Triton Tumor

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.

[Malignant Triton tumor of the nose--case report]

Malignant Triton tumor (MTT) is classified as a variant of a malignant peripherial nerve sheath tumor with a focal rhabdomyosarcomatous differentiation. Nearly one third of described MTTs were located at the head and neck region. In following paper we described a case of MTT of the external nose in a 24 year old man. The tumor was totally exised surgically with the broad margins. Histopathological diagnosis of the tumor was made on the surgical specimen, based on immunohistochemical analysis. Radiation therapy as the next step of treatment of choice was performed in presented case.