Acquisition of i(8q) as an early event in malignant triton tumors

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.

A case of malignant peripheral nerve sheath tumor with rhabdomyoblastic differentiation: malignant triton tumor

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.

A rare case of malignant triton tumor in the cerebellopontine angle

Malignant triton tumor (MTT) is defined as malignant peripheral nerve sheath tumor with rhabdomyoblastic differentiation. Intracranial MTT is extremely rare, and only four cases have been reported in the literature. Here, we report a case of MTT occurring in the cerebellopontine angle, and describe its histopathological characteristics, immunohistochemical features, and prognosis.

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Malignant triton tumors--complete surgical resection and adjuvant radiotherapy associated with improved survival

BACKGROUND

Malignant triton tumors (MTT) are a rare form of peripheral nerve sheath tumors that follows a particularly aggressive course. Given its rarity, only case reports and small series of patients have been published.

METHODS

A Pubmed search was conducted (1966-2009) using the terms "triton tumor," "rhabdomyosarcoma," and "malignant peripheral nerve sheath tumor." The reference lists of retrieved articles were searched. Cases were included when the diagnosis was clear, the patient underwent surgery, and follow-up data were available. Univariate and multivariate analyses were conducted for predictors of positive resection margin, local recurrence/progression, development of metastases, and mortality.

RESULTS

A total of 124 cases were included. The overall 5-year survival was 14% and the median time to death was 13 months. The overall local recurrence/progression rate was 50% and the median time to recurrence/progression was 6 months. On multivariate Cox proportional hazards analysis, positive margin status (HR 2.2, P = 0.01), local recurrence/progression (HR 3.1, P = 0.003), and development of metastases (HR 2.6, P = 0.003) were associated with mortality. Adjuvant radiotherapy was associated with improved survival (HR 0.4, P = 0.005).

CONCLUSION

Complete surgical resection and adjuvant radiotherapy should be the cornerstones of treatment for MTT.

Malignant triton tumor in a patient with Li-Fraumeni syndrome and a novel TP53 mutation

We report a 3-year-old boy with a malignant triton tumor (MTT) involving the left masticator space with local invasion and regional lymph node metastasis. Family history and detection of a novel germline TP53 mutation confirmed his diagnosis of Li Fraumeni syndrome (LFS). MTT has not been previously described in association with LFS. This case along with a comprehensive review of the literature, illustrate the importance of both somatic and germline TP53 mutations in the pathogenesis MTT. The tumor could not be resected and he was successfully treated with intensive induction chemotherapy, irradiation, and high-dose chemotherapy with autologous stem cell transplantation.

Malignant peripheral nerve sheath tumor with rhabdomyosarcomatous differentiation (malignant triton tumor)

Malignant peripheral nerve sheath tumors arise from Schwann cells or within existing neurofibromas and have a strong association with type 1 neurofibromatosis. These tumors are histologically diverse and may contain malignant areas of divergent mesenchymal differentiation, the most common of which is skeletal muscle (rhabdomyosarcoma). Malignant peripheral nerve sheath tumor with rhabdomyosarcomatous differentiation is also known as malignant triton tumor. Malignant triton tumor has a worse prognosis than classic malignant peripheral nerve sheath tumor does, and the correct diagnosis requires attention to the clinical history and knowledge of the complexities regarding its differential diagnosis. In this review we discuss the clinical, histopathological, immunohistochemical, and prognostic features of this rare neoplasm.

An imprinted locus epistatically influences Nstr1 and Nstr2 to control resistance to nerve sheath tumors in a neurofibromatosis type 1 mouse model

Cancer is a complex disease in which cells acquire many genetic and epigenetic alterations. We have examined how three types of alterations, mutations in tumor suppressor genes, changes in an imprinted locus, and polymorphic loci, interact to affect tumor susceptibility in a mouse model of neurofibromatosis type 1 (NF1). Mutations in tumor suppressor genes such as TP53 and in oncogenes such as KRAS have major effects on tumorigenesis due to the central roles of these genes in cell proliferation and cell survival. Imprinted genes expressed from only one parental chromosome affect tumorigenesis if their monoallelic expression is lost or duplicated. Because imprinted loci are within regions deleted or amplified in cancer, the parental origin of genomic rearrangements could affect tumorigenesis. Gene polymorphisms can vary tumor incidence by affecting rate-limiting steps in tumorigenesis within tumor cells or surrounding stroma. In our mouse model of NF1, the incidence of tumors mutant for the tumor suppressor genes Nf1 and Trp53 is strongly modified by a linked imprinted locus acting epistatically on two unlinked polymorphic loci, Nstr1 and Nstr2. This interaction of an imprinted locus and polymorphic susceptibility loci has profound implications for human mapping studies where the parental contribution of alleles is often unknown.

Molecular cytogenetic analysis in the study of brain tumors: findings and applications

Classic cytogenetics has evolved from black and white to technicolor images of chromosomes as a result of advances in fluorescence in situ hybridization (FISH) techniques, and is now called molecular cytogenetics. Improvements in the quality and diversity of probes suitable for FISH, coupled with advances in computerized image analysis, now permit the genome or tissue of interest to be analyzed in detail on a glass slide. It is evident that the growing list of options for cytogenetic analysis has improved the understanding of chromosomal changes in disease initiation, progression, and response to treatment. The contributions of classic and molecular cytogenetics to the study of brain tumors have provided scientists and clinicians alike with new avenues for investigation. In this review the authors summarize the contributions of molecular cytogenetics to the study of brain tumors, encompassing the findings of classic cytogenetics, interphase- and metaphase-based FISH studies, spectral karyotyping, and metaphase- and array-based comparative genomic hybridization. In addition, this review also details the role of molecular cytogenetic techniques in other aspects of understanding the pathogenesis of brain tumors, including xenograft, cancer stem cell, and telomere length studies.

Malignant triton tumor (MTT) of the neck

Malignant Triton Tumor (MTT) is a rare, malignant periphere nerve sheath tumor with rhabdomyoblastic differentiation. One third of described MTT's were located at the head and neck region. One third of these are associated with neurofibromatosis type 1. MTT most often appears in the third decade. MTT's are very aggressive tumors with early metastases and the overall survival is poor (26%). Therefore, early diagnosis and correct treatment is of utmost importance. We report a case of MTT of the left supraclavicular region in a 41-year-old man. We present the pathological findings, both light and immunohistochemically.