Malignant peripheral nerve sheath tumor (MPNST) frequently metastasizes to the lungs, although pleural metastasis is rare. This article reported a case of pleural metastasis of MPNST. The patient was a young man who presented with 1 week of shortness of breath with dry cough. He had a history of malignant peripheral nerve sheath tumor. The patient was diagnosed with MPNST pleural metastasis after a thoracoscopic pleural biopsy, which revealed short spindle cell hyperplasia, immunohistochemical staining for S-100(+), SOX-10(+), Ki-67(+) with a positive index of 20%, and H3K27Me3(-) in the pleural pathology.
恶性周围神经鞘膜瘤（malignant peripheral nerve sheath tumor，MPNST）常转移至肺，胸膜转移罕见。本文报道1例MPNST胸膜转移患者。患者青年男性，因“气促伴干咳1周”就诊。既往恶性周围神经鞘膜瘤病史。内科胸腔镜胸膜活检病理提示短梭形细胞增生，胸膜病理切片免疫组织化学染色S-100（+）、SOX-10（+）、Ki-67（+）阳性指数20%、H3K27Me3（-），诊断为MPNST胸膜转移。.

The blood vessel lumen is an extremely rare location for a benign peripheral nerve sheath tumor like schwannoma. Less than 10 cases have been previously reported. In this report, we present a case of a 68-year-old woman who had a soft tissue nodule at the posterior calf of her left leg during a physical examination. Pathological examination was performed after complete surgical excision. The patient underwent follow-up for 12 months after surgery without evidence of recurrence or any other complication. This is the first case of intravascular schwannoma reported as a cause of vein obstruction. Microscopically, the tumor was composed of Schwann spindle cells that were immunoreactive for S100 protein and SOX10. This tumor was surrounded by a well-defined vascular smooth muscle wall. Prospective series are required to improve the knowledge on the underlying mechanisms of intravascular schwannoma development.

Patients with the autosomal dominant tumor susceptibility syndrome neurofibromatosis type 1 (NF1) commonly develop plexiform neurofibromas (PNs) that subsequently transform into highly aggressive malignant peripheral nerve sheath tumors (MPNSTs). Understanding the process by which a PN transforms into an MPNST would be facilitated by the availability of genetically engineered mouse (GEM) models that accurately replicate the PN-MPNST progression seen in humans with NF1. Unfortunately, GEM models with Nf1 ablation do not fully recapitulate this process. This led us to develop P0-GGFβ3 mice, a GEM model in which overexpression of the Schwann cell mitogen neuregulin-1 (NRG1) in Schwann cells results in the development of PNs that progress to become MPNSTs with high frequency. However, to determine whether tumorigenesis and neoplastic progression in P0-GGFβ3 mice accurately model the processes seen in NF1 patients, we had to first prove that the pathology of P0-GGFβ3 peripheral nerve sheath tumors recapitulates the pathology of their human counterparts. Here, we describe the specialized methodologies used to accurately diagnose and grade peripheral nervous system neoplasms in GEM models, using P0-GGFβ3 and P0-GGFβ3;Trp53+/- mice as an example. We describe the histologic, immunohistochemical, and histochemical methods used to diagnose PNs and MPNSTs, how to distinguish these neoplasms from other tumor types that mimic their pathology, and how to grade these neoplasms. We discuss the establishment of early-passage cultures from GEM MPNSTs, how to characterize these cultures using immunocytochemistry, and how to verify their tumorigenicity by establishing allografts. Collectively, these techniques characterize the pathology of PNs and MPNSTs that arise in GEM models and critically compare the pathology of these murine tumors to their human counterparts.

N-Pyridinylthiophene carboxamide (compound 21) displays activity against peripheral nerve sheath cancer cells and mouse xenografts by an unknown mechanism. Through medicinal chemistry, we identified a more active derivative, compound 9, and found that only analogues with structures similar to nicotinamide retained activity. Genetic screens using compound 9 found that both NAMPT and NMNAT1, enzymes in the NAD salvage pathway, are necessary for activity. Compound 9 is metabolized by NAMPT and NMNAT1 into an adenine dinucleotide (AD) derivative in a cell-free system, cultured cells, and mice, and inhibition of this metabolism blocked compound activity. AD analogues derived from compound 9 inhibit IMPDH in vitro and cause cell death by inhibiting IMPDH in cells. These findings nominate these compounds as preclinical candidates for the development of tumor-activated IMPDH inhibitors to treat neuronal cancers.

OBJECTIVE: Sarcomas are a complex group of highly aggressive and metastatic tumors with over 100 distinct subtypes. Because of their diversity and rarity, it is challenging to generate multisarcoma signatures that are predictive of patient outcomes.
METHODS: Here, we identify a DNA methylation signature for progression and metastasis of numerous sarcoma subtypes using multiple epigenetic and genomic patient data sets. Malignant Peripheral Nerve Sheath Tumors (MPNSTs) are highly metastatic sarcomas with frequent loss of the histone methyltransferase, PRC2. Loss of PRC2 is associated with MPNST metastasis and plays a critical noncanonical role in DNA methylation.
RESULTS: We found that over 900 5\'-C-phosphate-G-3\' (CpGs) were hypermethylated in MPNSTs with PRC2 loss. Furthermore, we identified eight differentially methylated CpGs in the IL17D/RD family that correlate with the progression and metastasis of MPNSTs in two independent patient data sets. Similar trends were identified in other sarcoma subtypes, including osteosarcoma, rhabdomyosarcoma, and synovial sarcoma. Analysis of scRNAseq data sets determined that IL17D/RD expression occurs in both the tumor cells and the surrounding stromal populations.
CONCLUSIONS: These results might have broad implications for the clinical management and surveillance of sarcoma.

Psuedomyxoma peritonei is an infrequent clinical entity characterised by intraperitoneal mucinous/gelatinous ascites produced by the cancerous cells. It has been associated with gastrointestinal, gynaecological, lung and breast tumours. It is commonly asymptomatic and is most often detected incidentally on abdominopelvic imaging or laparoscopy. Higher histological grade of the tumour shows increased metabolic activity on 18F-Fluorodeoxyglucose (FDG) positron-emission tomography (PET) computed tomography (CT). It has been rarely reported in patients with sarcoma. We hereby present an interesting case of incidentally diagnosed pseudomyxoma peritonei on 18FDG PET-CT scan of a patient with soft tissue sarcoma of peripheral nerve sheath.

Retroperitoneal spindle cell neoplasms are diagnostically challenging. Malignant peripheral nerve sheath tumours (MPNSTs) can sometimes present as sporadic primary retroperitoneal tumours. MPNSTs are usually high-grade and highly aggressive tumours and are associated with a poor prognosis. Low-grade MPNSTs are very rarely described. This current case report describes a case of sporadic primary low-grade MPNST presenting as retroperitoneal spindle cell neoplasm. The diagnosis, imaging and immunohistopathological findings, as well as its successful surgical management, are presented.

Most malignant peripheral nerve sheath tumors (MPNSTs) are clinically aggressive high-grade sarcomas, arising in individuals with neurofibromatosis type 1 (NF1) at a significantly elevated estimated lifetime frequency of 8%-13%. In the setting of NF1, MPNSTs arise from malignant transformation of benign plexiform neurofibroma and borderline atypical neurofibromas. Composed of neoplastic cells from the Schwannian lineage, these cancers recur in approximately 50% of individuals, and most patients die within five years of diagnosis, despite surgical resection, radiation, and chemotherapy. Treatment for metastatic disease is limited to cytotoxic chemotherapy and investigational clinical trials. In this article, we review the pathophysiology of this aggressive cancer and current approaches to surveillance and treatment.

A heifer and a dairy cow were presented to our practice with cutaneous masses on the left side of their necks. Each mass had a diameter of approximately 20 cm. Both tumors had increased in size in recent weeks and were now prone to injuries from the stable equipment. Both animal owners agreed to surgical removal, which was performed under sedation and local anesthesia on a bovine treatment crush. The subsequent histopathological examinations of the extirpates revealed a melanocytoma in the young heifer and a cutaneous peripheral nerve sheath tumor (PNST) in the dairy cow. Both cases were benign tumors. The postoperative course was without complications and no recurrences were observed even more than a year later. No comparable tumors were found in related animals or in the offspring.
Ein Jungrind und eine Milchkuh wurden in unserer Praxis mit im Durchmesser ca. 20 cm großen Umfangsvermehrungen, die sich jeweils an der linken Halsseite befanden, vorgestellt. Beide Geschwulste hatten in den letzten Wochen an Umfang zugenommen und es bestand die Gefahr, dass es zu Verletzungen durch die Stalleinrichtungen kommt. Beide Tierhalter stimmten einer chirurgischen Entfernung, die unter Sedation und Lokalanästhesie auf einem Kippstand für Rinder durchgeführt wurde, zu. Die anschließenden histopathologischen Untersuchungen der Exstirpate ergaben bei dem Jungrind ein Melanozytom und bei der Milchkuh einen kutanen Nervenscheidentumor. In beiden Fällen handelte es sich um gutartige Tumore. Der postoperative Verlauf war komplikationslos und auch über ein Jahr später konnten keine Rezidive beobachtet werden. Bei verwandten Tieren und bei später geborenen Kälbern konnten solche Tumore nicht festgestellt werden.

The chapter is focused on the neoplastic peripheral nerve lesions, which primarily involve \"cranial and paraspinal nerves,\" as outlined in the CNS volume (WHO_Classification_of_Tumours_Editorial_Board, 2021). These include classic peripheral nerve sheath tumors such as schwannoma, neurofibroma, intraneural perineurioma, and malignant peripheral nerve sheath tumors, with their variants as well as new and more precisely defined entities, including hybrid nerve sheath tumors and malignant melanotic nerve sheath tumor (previously melanotic schwannoma).