Malignant peripheral nerve sheath tumor of the orbit is an exceedingly rare entity. These tumors exhibit locally aggressive behavior, recurrences, distant metastasis, and poor response to existing treatment protocols. Orbital nerve sheath tumors are often associated with neurofibromatosis 1, and malignant transformation of neurofibroma into malignant nerve sheath tumor has also been seen. The recommended treatment for localized disease is radical or wide surgical excision to achieve negative margins followed by chemoradiation. For extensive disease, chemotherapy and radiotherapy can be utilized to stabilize the disease. Due to poor response and outcomes with current regimens, the focus has been shifted to approaches utilizing molecular targets and immunological agents. Despite all the advancements, the outcomes still remain discouraging for moderate- to high-grade lesions and thus necessitate studies to design promising treatment modalities.

Primary intraosseous malignant peripheral nerve sheath tumors (MPNSTs) are rare yet highly aggressive neoplasms originating from peripheral nerves. Typically manifesting as soft tissue masses accompanied by pain or functional impairment, these tumors pose significant challenges in management. Surgical intervention remains the cornerstone of treatment for patients with MPNST lacking distant metastasis, with generally modest success rates. In cases of recurrence and metastasis, the pursuit of effective systemic therapies has been a focus of clinical investigation. Herein, we present a case study involving an elderly female patient with refractory MPNST. In light of surgical limitations, a multimodal therapeutic approach combining chemotherapy, denosumab, and subsequent administration of anlotinib was pursued following collaborative consultation. This regimen yielded noteworthy clinical benefits, exemplifying a promising avenue in the management of challenging MPNST cases.

Primary pulmonary malignant peripheral nerve sheath tumor (MPNST) is a rare soft tissue sarcoma with a low incidence, poor prognosis and limited treatment options. The present study reported a case of lung MPNST in a 63-year-old male patient without any pulmonary symptoms. Immunohistochemical analysis of the tumor indicated a programmed death-ligand 1 (PD-L1) expression tumor proportion score of 60%. A total of six courses of sintilimab were used in this patient and a remarkable response was achieved. In summary, sintilimab single-agent immunotherapy may be a novel treatment for pulmonary MPNST. When encountering analogous cases in the future, oncologists can test for the expression of PD-L1 in patients to guide the therapy\'s design.

UNASSIGNED: Malignant peripheral nerve sheath tumors (MPNSTs) are rare malignant soft-tissue sarcomas arising from peripheral nerves. Little data exist regarding MPNST originating intracranially. Here, we present a 7th/8th nerve complex MPNST, discuss the treatment strategy and patient outcome, and provide a comprehensive review of existing literature.
UNASSIGNED: Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, PubMed and crossed references were queried, yielding 37 publications from 1952 to the present. Fifty-three cases of primary intracranial and extra-axial MPNST were identified.
UNASSIGNED: We additionally report a 40-year-old female presented with acute onset dizziness and subsequent hearing loss with associated right-sided facial numbness. Magnetic resonance imaging revealed a 0.5 cm × 1.7 cm enhancing lesion within the right internal auditory canal extending into the cerebellopontine angle. The patient was initially treated with retro sigmoid craniotomy for tumor resection followed by a trans labyrinth approach for residual tumor resection. She completed adjuvant fractionated radiation therapy and underwent facial nerve transfer to restore complete hemifacial paralysis. The most common cranial nerves involved were V and VIII (43.4% each), with 66% of patients male and 34% female. The average age was 43.4 ± 17.4 years. The mean survival time for reported non-survivors after tissue diagnosis was 15 ± 4 months. Two-year survival for patients receiving gross total resection was 33.3% versus 22.8% with subtotal resection.
UNASSIGNED: MPNSTs comprise a group of highly aggressive neoplasms that rarely arise intracranially. Gross total surgical resection should be pursued when feasible.

Malignant peripheral nerve sheath tumors (MPNSTs) are rare high-grade sarcomas arising from the peripheral nerves or peripheral nerve sheath cells. MPNSTs rarely occur in the soft tissue, especially in the uterine cervix. Few cases of cervical MPNST have been reported in the literature. The present study reports the case of a 36-year-old female patient who presented with vaginal bleeding. A cervical mass was detected by vaginal ultrasonography and the patient was diagnosed with MPNST via assessment of the morphological and immunohistochemical features of the tumor after surgery. The patient received chemotherapy and radiotherapy following surgery, and at 8 months post-treatment, had no recurrence or metastasis. Furthermore, the present study summarizes the characteristics of all reported cases of cervical MPNST and their potential differential diagnosis with other spindle cell tumors.

Malignant triton tumor (MTT) is a highly aggressive malignant neoplasm, classified as a variant of malignant peripheral nerve sheath tumor with rhabdomyoblastic differentiation. There are few reports that MTT occurred in urogenital system. In the present study, we report the first MTT occurring in the uterus. A 57-year-old woman came to the emergency department due to persistent vaginal bleeding for 2 months. The gynecological palpation found that a club-shaped excrescence existed in the vagina about 7 cm × 3 cm × 3 cm. The mass located in the lower segment of the uterus and the cervix was confirmed by gynecological vaginal ultrasound and magnetic resonance imaging, which was preliminarily diagnosed as cervical carcinoma. After neoplasm punch biopsy, the pathological diagnosis was malignant triton tumor. The patient finally lost follow-up. This is the first report about MTT in the uterus and suggests that pathological biopsy combined with imaging examination is necessary for the diagnosis of rarely MTT.

Mesenchymal spindle cell tumors with kinase fusions, often presenting in superficial or deep soft tissue locations, may rarely occur in bone. Herein, we describe the clinicopathologic and molecular data of eight bone tumors characterized by various kinase fusions from our files and incorporate the findings with the previously reported seven cases, mainly as single case reports. In the current series all but one of the patients were young children or teenagers, with an age range from newborn to 59 years (mean 19 years). Most tumors (n = 5) presented in the head and neck area (skull base, mastoid, maxilla, and mandible), and remaining three in the tibia, pelvic bone, and chest wall. The fusions included NTRK1 (n = 3), RET (n = 2), NTRK3 (n = 2), and BRAF (n = 1). In the combined series (n = 15), most tumors (73%) occurred in children and young adults (<30 years) and showed a predilection for jaw and skull bones (40%), followed by long and small tubular bones (33%). The fusions spanned a large spectrum of kinase genes, including in descending order NTRK3 (n = 6), NTRK1 (n = 4), RET (n = 2), BRAF (n = 2), and RAF1 (n = 1). All fusions confirmed by targeted RNA sequencing were in-frame and retained the kinase domain within the fusion oncoprotein. Similar to the soft tissue counterparts, most NTRK3-positive bone tumors in this series showed high-grade morphology (5/6), whereas the majority of NTRK1 tumors were low-grade (3/4). Notably, all four tumors presenting in the elderly were high-grade spindle cell sarcomas, with adult fibrosarcoma (FS)-like, malignant peripheral nerve sheath tumor (MPNST)-like and MPNST phenotypes. Overall, 10 tumors had high-grade morphology, ranging from infantile and adult-types FS, MPNST-like, and MPNST, whereas five showed benign/low-grade histology (MPNST-like and myxoma-like). Immunohistochemically (IHC), S100 and CD34 positivity was noted in 57% and 50%, respectively, while co-expression of S100 and CD34 in 43% of cases. One-third of tumors (4 high grade and the myxoma-like) were negative for both S100 and CD34. IHC for Pan-TRK was positive in all eight NTRK-fusion positive tumors tested and negative in two tumors with other kinase fusions. Clinical follow-up was too limited to allow general conclusions.

BACKGROUND: Malignant peripheral nerve sheath tumor (MPNST) is a rare and aggressive soft tissue sarcoma that poses a major diagnostic and therapeutic challenge.
METHODS: We retrospectively reviewed patients with head and neck MPNSTs treated in our hospital from 2000 to 2021. The clinical features, pathological manifestations, treatments, and prognoses were summarized. We also reviewed the literature, focusing on MPNST in the mandible and maxilla. The study population consisted of five women and five men aged 22-75 years (mean age, 49 years). Of the 10 patients, 7 were initial cases and 3 were recurrent cases. All lesions were sporadic. The most common site was the mandible. The most frequently encountered symptoms were a progressive mass and local swelling. Complete or partial loss of trimethylation at lysine 27 of histone H3 (H3K27me3) was evident on staining in four of nine cases (one case was excluded due to lack of tissue for evaluation of loss of H3K27me3). The 2- and 5-year disease-specific survival rates were 86% and 43%, respectively. The average survival time was 64 mo.
CONCLUSIONS: MPNST is a highly malignant tumor with a poor prognosis, prone to a high risk of recurrence and distant metastasis. Complete surgical resection is the main treatment.

UNASSIGNED: Malignant peripheral nerve sheath tumors (MPNSTs) are one of the rarest soft-tissue sarcomas with a prevalence of 0.001% in the general population. It is closely associated with a unique neurocutaneous stigmata under the spectrum of the dermatological manifestations of neurofibromatosis type 1 (NF1). Almost 81% of MPNST arises from a precursor neuroma, and multifocality of these lesions is extremely rare, making up to 0.001% of cases. Moreover, spinal cases are extremely uncommon with only four cases reported internationally. Here, we present the fifth and sixth spinal MPNST cases with a brief review of literature.
UNASSIGNED: We describe two unusual cases of multifocal MPNST in relation to NF1 occurring in the spinal cord. Both patients presented with local pain and myelopathic symptoms. The two patients underwent wide surgical resection, followed by neoadjuvant radiotherapy and reported immediate postoperative improvement of the presented complaint; however, one patient suffered from rapid recurrence and metastasis.
UNASSIGNED: Due to the scarcity of spinal cases related to MPNST, no clear guidelines regarding the management of these cases are set in the literature. Histopathological diagnosis remains as the most pivotal diagnostic tool as they can mimic other peripheral nerve sheath lesions, such as neuromas and schwannomas, in imaging. Cases that were managed by early surgical intervention in addition to neoadjuvant radiotherapy reported the best outcome. However, cases of MPNST in concomitance with NF1 were found to be resistant to both chemo and radiotherapy and have high recurrence rate.

Malignant peripheral nerve sheath tumor (MPNST) of the scalp is rare. These lesions are associated with neurofibromatosis type 1 (NF1), but patients had been reported without NF1 also. We tried to analyze the difference between the clinical course and outcome of the patient with MPNST having stigmata of NF1 and without it. We included five patients treated over 3 years between July 2018 and July 2021 with diffuse scalp MPNST. Two of these five patients with MPNST of the scalp had neurocutaneous stigmata of NF1. Three were female and two males with an average age of 38.40 ± 18.48 years-the youngest with NF1 being a 19-year-old female. We found dull aching pain as the most typical complaint in all patients and a repeated episode of generalized seizure in one patient. In these cases, two patients with NF1 have highly vascular tumors and attained large sizes greater than 30 cm. These two cases required preoperative digital subtraction angiography (DSA) and embolization with n-butyl acrylate. Total excision of the tumor was done in all patients with radiotherapy. Metastases within 1 year were noted in two patients with NF1, and one of these two succumbed to her illness. The rest of the three patients without NF1 are under follow-up with no evidence of disease with a maximum follow-up of 2 years. Large MPNST (size > 20 cm) are rare and reported to have been associated with and without NF1. Patients with scalp MPNST with NF1 can achieve larger size with fast progression of tumor size and higher chances of recurrence and metastases.