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12 recordsLinked to original sources
PubMed1989

Malignant peripheral nerve sheath tumor (MPNST) showing perineurial cell differentiation.

We report a malignant peripheral nerve sheath tumor (MPNST) showing the unusual immunohistochemical feature of epithelial membrane antigen (EMA) immunoreactivity in a 52-year-old man. The tumor, located in the left paravertebral muscles, was composed of both cellular and myxoid areas. Spindle-shaped tumor cells were arranged in longitudinal cell cords, in a storiform pattern, and in whorled structures. Ultrastructurally, the tumor cells had many interdigitating cell processes, primitive cell junctions, and discontinuous external laminae. These histological and ultrastructural features were most consistent with those of an MPNST; but on immunohistochemistry, the tumor cells reacted for epithelial membrane antigen rather than for S-100 protein or Leu-7. Because EMA-immunoreactivity was recently demonstrated in perineurial cells, we concluded that the tumor was an MPNST mainly composed of tumor cells showing perineurial cell differentiation.

Cell Differentiation↗
PubMed2026

Combination of EZH2 and MEK inhibitors as an effective therapy for neurofibromatosis type 1-associated malignant peripheral nerve sheath tumors.

BACKGROUND: Neurofibromatosis type 1 (NF1)-associated malignant peripheral nerve sheath tumors (MPNSTs) are aggressive sarcomas with poor outcomes and limited therapeutic options. Although mitogen-activated protein kinase kinase (MEK) inhibitors are active in benign plexiform neurofibromas, their efficacy in MPNST treatment is modest. Enhancer of zeste homolog 2 (EZH2) inhibitors are preclinically efficacious in MPNST treatment, but their mechanisms of action remain unclear. We evaluated the therapeutic potential and molecular mechanism of combined EZH2 and MEK inhibitors in NF1-associated MPNST. METHODS: Five human NF1-associated MPNST cell lines were exposed to EZH2 and/or MEK inhibitors. Cell growth and apoptosis were quantified over time. Therapeutic efficacy was tested in a subcutaneous xenograft model. Proliferation and apoptosis in tumors were assessed using standard histologic markers, and intracellular localization of phosphorylated extracellular signal-regulated kinase (pERK) was examined using fluorescent immunohistochemistry. RESULTS: Monotherapy with EZH2 or MEK inhibitors reduced proliferation and increased apoptosis across all MPNST lines. Combination therapy produced greater tumor cell growth suppression and marked increases in apoptosis. In vivo, the combination significantly delayed tumor progression compared with monotherapy, with concomitant reductions in proliferative indices and increases in apoptotic indices. EZH2 inhibitor limited nuclear pERK entry. CONCLUSIONS: Dual EZH2 and MEK inhibitors yield additive antitumor activity in NF1-associated MPNST. Although the molecular mechanism could not be elucidated, our findings suggest that EZH2 inhibitors exhibited a polycomb repressive complex 2-independent, noncanonical mechanism characterized by pERK nuclear translocation restriction, providing a strong rationale for clinical evaluation of this combination in NF1-associated MPNST.

EZH2 inhibitor↗
PubMed2026

Personalized medicine strategy for MPNSTs: using precision oncology on PDOX models to inform tumor boards.

BACKGROUND: Malignant peripheral nerve sheath tumors (MPNSTs) are a heterogeneous group of aggressive soft tissue sarcomas with poor prognosis. Currently there is a lack of effective treatments for MPNSTs. Here, we propose a personalized medicine approach that integrates a precision oncology strategy guided by MPNST genomic analysis, with a functional validation of treatment response in an orthotopic xenograft model (PDOX) derived from the same MPNST. METHODS: Comprehensive whole genome sequencing analysis was performed in primary MPNSTs, relapses and (in one case) metastases, following disease progression in two independent individuals. Matched MPNST PDOX models were generated by orthotopically implanting tumor fragments near the sciatic nerve of immunodeficient mice. Candidate targeted combination therapies were prioritized based on genomic alterations and tested in vivo in the PDOX models. RESULTS: The feasibility of the developed strategy is illustrated for two MPNST patients, one Neurofibromatosis type 1 (NF1) individual that developed two independent MPNSTs and another sporadic MPNST case with multiple metastatic relapses. Genomic analysis revealed a remarkable degree of genomic stability across primary MPNSTs and their successive relapses in each patient, and even metastases in one individual. While based on a small number of cases requiring additional analyses, this finding aligns with previous evidence suggesting a fair genomic conservation throughout tumor evolution. This stability supports the identification of consistent therapeutic vulnerabilities throughout disease progression. Among the therapies tested, co-treatment of MEK inhibitor (MEKi) plus bromodomain inhibitor (BETi) elicited the highest antitumor activity, resulting in approximately 60% tumor volume reduction in the sporadic MPNST PDX model, whose patient has been receiving this therapy for eight months with sustained remission. CONCLUSIONS: This study demonstrates the feasibility and clinical utility of integrating genomic-driven precision oncology with PDOX-based functional testing for MPNSTs. This strategy may support molecular tumor boards (MTBs) in their treatment decisions. The observed genomic stability supports the use of longitudinal tumor profiling to guide treatment, and the success of MEKi+BETi highlights its potential as a combination therapy for MPNSTs.

Precision Medicine↗
PubMed2026

Molecular subgroups of human malignant peripheral nerve sheath tumors are conserved in canines.

Malignant peripheral nerve sheath tumors (MPNST) are aggressive sarcomas of Schwann cell lineage with poor prognosis in both humans and dogs. While rare in humans, MPNSTs occur more frequently in dogs and share histomorphological and clinical features. Recent methylome and transcriptome analyses have identified two molecular subgroups of human MPNST with distinct oncogenic signaling pathways and prognostic implications; however, it remains unclear if these subgroups also exist in canines. Given their higher incidence and biological similarities to human disease, canine MPNSTs represent a promising comparative model to investigate molecular subtypes and evaluate novel therapeutic strategies. To characterize canine MPNST and assess molecular parallels with the human subgroups, we applied laser-capture microdissection (LCM) followed by RNAsequencing to analyze tumor tissue from 20 canine MPNST. Principle component and differential gene expression analyses identified two clearly distinct transcriptional clusters corresponding to spindle cell and epithelioid MPNST variants, respectively. Unsupervised cross-species comparison aligned the two canine clusters with the human G1 and G2 subgroups. Accordingly, one cluster was characterized by SHH pathway activation and increased cell cycle activity, while the other showed non-canonical WNT pathway, Schwann cell-like features and marked macrophage infiltration. Immunohistochemistry further demonstrated loss of H3K27me3, p-ERK activation and β-catenin signaling by IHC in a subset of tumors. These findings support the value of canine MPNST as clinically amenable model for structured assessment of novel therapeutic approaches to benefit patients of both species.

Canine cancer model↗
PubMed1986

Malignant peripheral nerve sheath tumors. A clinicopathologic study of 120 cases.

A review was done of 120 cases of malignant peripheral nerve sheath tumor (MPNST) seen during a 71-year period. Of the 120 patients, 52 were males and 68 were females with a mean age at diagnosis of 35.3 years; 12 patients were younger than 20 years. The series included 62 (52%) patients with neurofibromatosis, 13 (11%) with postradiation sarcomas, and 19 (16%) with metaplastic foci. The incidence of MPNST arising in neurofibromatosis was 4.6% in the current series and 0.001% in the general clinic population. Tumors greater than 5 cm and the presence of neurofibromatosis adversely affected the prognosis (P less than 0.05). When both features were present, survival was greatly decreased. Patients with tumor in the extremities did better than those with head or neck lesions. Metaplastic foci or previous radiation at the tumor site did not alter the prognosis. Each tumor was graded 1 to 4 on the basis of cellularity, pleomorphism, mitotic index, and necrosis. No significant correlation was noted between survival and either grade or mitotic rate. Survival was improved when total rather than subtotal resection was done. This was most marked in patients with a small lesion, which may reflect the difficulty in adequately excising large tumors. Adjuvant radiation or chemotherapy did not appear to affect survival. The MPNST is an aggressive uncommon neoplasm, and large tumor size, the presence of neurofibromatosis, and total resection are the most important prognostic indicators.

Adolescent↗
PubMed1987

Malignant peripheral nerve sheath tumor. An immunohistochemical study of 62 cases.

Malignant peripheral nerve sheath tumor (MPNST) commonly presents a diagnostic challenge and may resemble a variety of other soft tissue neoplasms microscopically. The authors have examined 62 examples of MPNST immunohistochemically, using antibodies to S-100 protein, myelin basic protein (MBP), and Leu-7, all of which are potential neural markers. Sixty-eight percent of all cases expressed at least one of these three determinants, representing a higher rate of immunoreactivity than that seen for single nervous system antigens in previous studies. Conjoint reactivity for S-100/Leu-7, S-100/MBP, and MBP/Leu-7 was seen in 34%, 34%, and 24% of cases, respectively. This coexpression of antigens is important, because none of them in isolation is immunospecific for nerve sheath tumors. In addition, stains for epithelial membrane antigen were reactive in two epithelioid tumors in this series, and eight spindle-cell neoplasms demonstrated desmin positivity. Analyses for cytokeratin, carcinoembryonic antigen, and Factor VIII-related antigen were negative in all cases. These results indicate an overlap between the immunocytochemical attributes of malignant peripheral nerve sheath tumors and other soft tissue sarcomas and emphasize the desirability of assessing multiple neural markers in such cases.

Antigens↗
PubMed1989

Malignant peripheral nerve sheath tumors and spindle cell sarcomas: an immunohistochemical analysis of multiple markers.

An immunocytochemical study using a panel of commercially available antisera, has been performed to distinguish on the basis of their immunoreactivity a series of spindle cell sarcomas diagnosed solely on the histologic features: 11 malignant schwannomas (MS), 8 leiomyosarcomas (LMS) and 3 malignant fibrous histiocytomas (MFH). The results have been compared with those obtained in 12 benign and 8 malignant peripheral nerve sheath tumors (MPNST) in which the microscopic diagnosis was supported by their origin in a nerve trunk and/or in von Recklinghausen's (vR) disease. The following antisera were used: anti-S-100 protein, anti-Leu-7, anti-neuron specific enolase (NSE), anti-myelin basic protein (MBP), anti-glial fibrillary acidic protein (GFAP) and anti-actin. S-100 protein was present in 100% of benign and malignant peripheral nerve tumors and in 7/11 (63%) of MS diagnosed on histological basis only and in 3/8 (37%) LMS. MFH were negative. Leu-7 positivity was observed in 8/12 (66%) and 6/8 (75%), respectively, in benign and malignant PNS neoplasms, in 5/11 (45%) MS, 4/8 (50%) LMS and 2/3 (66%) MFH. NSE was present in 7/12 (58%) and 6/8 (75%), respectively, in benign and malignant PNS tumors, in 6/11 (54%) MS and in 1/8 (12%) LMS. MFH were negative. MBP resulted negative in peripheral nerve neoplasms and spindle cell sarcomas. GFAP positivity was observed in 2/12 (16%) and 1/8 (12%), respectively, in benign and malignant PNS neoplasms. All spindle cell sarcomas were negative. All cases of MPNST and spindle cell sarcomas showed actin immunoreactivity. These results indicate that: (1) MBP, Leu-7 and NSE do not represent markers of schwannian differentiation; (2) GFAP, although rarely expressed, may indicate schwannian differentiation, and (3) malignant peripheral nerve neoplasms and LMS share immunoreactivity for S-100, Leu-7, NSE and actin, therefore they cannot be differentiated on immunocytochemical basis using commercially available antisera.

Actins↗
PubMedDate not supplied

Evaluation of spindle cell tumors.

The most important aspect of any evaluation of spindle cell tumors in the skin or superficial soft tissues is the clinical examination, as a great deal can be learned from the location, appearance, and size of the tumor in question. As recounted in this chapter, the histologic features of these tumors may also be distinctive; however, in some instances, histologic examination alone is insufficient for diagnosis. In such cases, electron microscopy holds considerable promise, but the technique is too dependent upon both the availability of adequately preserved tissues and access to the technique itself. As a result, immunohistochemistry remains the favored approach to most problematic lesions. In our experience, at least 90% of histologically enigmatic tumors will exhibit a characteristic immunophenotype, the remainder usually being indeterminant for a specific pattern of differentiation. The latter outcome is often the result of improper tissue preservation, but may also reflect the primitive nature of some neoplasms. Fortunately, the least common outcome is an ambiguous or "mixed-lineage" phenotype, in which neither one of two or more patterns of differentiation is resolved with certainty. The most common settings in which these problems arise are the separation of MPNST from LMS, and the recognition of melanocytic lesions as distinct from tumors of peripheral nerve sheath. The latter is clearly of greatest clinical concern, and should be the focus of additional study.

Carcinoma, Squamous Cell↗
PubMed1991

Maxillofacial malignant peripheral nerve sheath tumours.

The clinical and pathological features of 7 patients with MPNST in the maxillofacial area are reviewed. They occurred in five men and two women; ages ranged from seven to eighty years. The parotid area and infratemporal fossa were the commonest sites (two cases each), followed by the lower lip, cheek and central mandible (one case each). Two had the antecedent of an excised neurofibroma, one with von Recklinghausen's disease and radiotherapy, that had recurred many times. Pathological slides were revised. Immunohistochemistry with S-100 protein was positive in 6 of 7 cases; electron microscopy confirmed the diagnosis in 3 cases. None showed divergent differentiation. Surgical treatment was performed in all, with or without radiotherapy. Surgical margins were positive in five cases. Recurrence took place in six and was multiple in three. Surgical salvage of the local recurrences produced satisfactory results in 3 of the 6 cases. One patient developed lung metastasis.

Adolescent↗
PubMed2025

Integrated genomic analysis of NF1-associated peripheral nerve sheath tumors: an updated biorepository dataset.

Neurofibromatosis type 1 (NF1) is an inherited neurocutaneous condition that predisposes to the development of peripheral nerve sheath tumors (PNST) including cutaneous neurofibromas (CNF), plexiform neurofibromas (PNF), atypical neurofibromatous neoplasms of uncertain biologic potential (ANNUBP), and malignant peripheral nerve sheath tumors (MPNST). The Johns Hopkins NF1 biospecimen repository promotes the successful advancement of therapeutic developments for NF1-associated PNST through acquisition and genomic analysis of human tumor specimens. RNA sequencing (RNAseq) and whole exome sequencing (WES) data were generated from 73 and 114 primary human tumor samples, respectively. These pre-processed data, standardized for immediate computational analysis, are accessible through the NF Data Portal, allowing immediate interrogation. This dataset combines new and previously released samples, offering a comprehensive view of the entire cohort sequenced. As a dedicated effort to systematically bank tumor samples from people with NF1, in collaboration with molecular geneticists and computational biologists, the Johns Hopkins NF1 biospecimen repository offers access to tissue samples and genomic data to promote the advancement of NF1-related tumor biologic insights and therapies.

Humans↗
PubMed1992

[Neurosarcoma associated with Von Recklinghausen disease: apropos of 25 cases observed at the Gustave Roussy Institute from 1967 to 1990].

In the absence of systematic immunohistochemistry investigations, only 25 cases (out of 69) clearly diagnosed as neurosarcoma due to the association with Von Recklinghausen disease (ie, neurofibromatosis type 1) and treated at the Institut Gustave Roussy were included in the present study. Neurosarcoma consists of a neurocristopathy whose cells migrate to several parts of the body in order to constitute neuroglia, Schwann cells, pigmented and endocrinal tissues. From 1967 to 1990, 25 cases of such neurosarcomas associated with a neurofibromatosis type 1 were seen at our institute. Three different histological terms exist for this tumour: malignant schwannoma, neurosarcoma, and more recently, malignant peripheral nerve sheath tumours (MPNST). The median age (23 years) of the patients with neurofibromatosis type 1 is lower than that of patient with isolated neurosarcoma. Their sex ratio is 2/1. Primary tumour surgical exeresis was performed in all cases, with poor results in 7. Post-operative radiation therapy was not systematically used in this series. It was administered only in cases with incomplete surgical exeresis or when a local recurrence occurred. Adjuvant CYVADIC (doxorubicin, procarbazine, cyclophosphamide, vincristine) chemotherapy was administered in 5 cases, of in cases of relapse (8). All cases but 2 (the most recent ones) relapsed within 1 to 226 months (median 7 months). In addition, 13 patients developed metastases. Overall, the 2-year and 4-year survival rates were 41% and 18%, respectively. Our observations confirm the very poor prognosis for the association of neurofibromatosis type 1 and neurosarcoma. This finding should lead to systematically associate radical surgical exeresis, post-operative irradiation and adjuvant chemotherapy in the treatment of these patients.

Adolescent↗
PubMed1985

Case report of malignant primary nerve sheath tumor arising in the female pelvis.

This paper reports a malignant primary nerve sheath tumor (MPNST) which originated in the obturator nerve in a 54-year-old woman. That the tumor originated in the nerve sheath is supported by the site of occurrence, which was consistent with the obturator nerve, an arrangement of cells similar to that in schwannoma, and that extracellular basement membrane was noted ultrastructurally. This tumor was classified not as malignant schwannoma but as a nerve sheath fibrosarcoma because the matrix of tumor tissues contained abundant mucinous materials, some tumor cells were fibroblastic, and the clinical change was rapid. In general, with plexiform neurofibroma there is a familial manifestation and it occurs as a complication of von Recklinghausen's disease, associations not demonstrated in this patient. From these findings, this tumor is considered to be an extremely rare nerve sheath fibrosarcoma which originated from a malignant change in a sporadic and solitary plexiform neurofibroma.

Collagen↗