Approximately 45% of benign peripheral nerve sheath tumors(PNST) occur in head and neck regions. Malignant peripheral nerve sheath tumors (MPNST) are less common and only 815%- of these tumors occur in head and neck region. In this study, we aimed at evaluating the demographic characteristics, pathologic findings, locations, main clinical presentations and family history of these tumors in head and neck regions.Patients and In a cross sectional and retrospective study, we analyzed head and neck peripheral nerve sheath tumors in patients who referred to Amir-Aalam Hospital affiliated toTehran University of Medical Sciences for 10 years (1996 to 2005). There were 113 cases with a kind of nerve sheath tumor; the female/male ratio was 1.09. The frequency of schwannoma, neurofibroma and MPNST was 66.37%, 30.1% and 3.53%, respectively including 39 cases of acoustic neuroma, 18 cases of cervical nerve trunk involvement, 12 cases of facial nerve involvement, 11 cases of the 10th cranial nerve PNST and only one case of cervical sympathetic nerve involvement. Schwannomas are the most common types of PNSTs seen in head and neckregions, and aucoustic neuroma comprises the majority of them. About 25- 45% of extracranial schwannomas also occur in head and neck regions that usually present a slow growing of the mass lesion and various mass effects. Although neurofibroma and MPNSTs are less common, they must be kept in mind as differential diagnoses of other benign and malignant lesions in this region.

Malignant peripheral nerve sheath tumors (MPNST) are rare, aggressive soft tissue sarcomas that arise from peripheral nerves and often present a diagnostic and therapeutic challenge. They can occur sporadically or in association with neurofibromatosis type 1 (NF1), a genetic disorder caused by mutations in the NF1 gene. This report presents the unique case of a 33-year-old male with progressive dry cough, hoarseness, and neck swelling who underwent a total thyroidectomy, revealing a high-grade malignant peripheral nerve sheath tumor invading the thyroid. FDG PET/CT led to the additional diagnosis of NF1. This case stands out due to the rarity of finding an MPNST within the thyroid and the simultaneous identification of NF1. It underscores the importance of screening MPNST patients for NF1 and vice versa, spotlighting the expanding role of FDG PET/CT in comprehensive evaluations. To our knowledge, this report presents the first case of NF1-associated MPNST with thyroid involvement worldwide.

ntroduction:Malignant peripheral nerve sheath tumors (MPNSTs) are very rare. Malignant triton tumor is an aggressive variety of MPNSTs with rhabdomyoblastic differentiation. In this study we reported the clinical, radiographic, histopathologic and immunohistochemical features of an intramandibular malignant triton tumor.Case Report:The patient was a 31 year-old male who was referred to maxillofacial surgery ward of Mashhad dental school with a painful swelling in the anterior part of mandible and facial asymmetry. After histopathological evaluation, surgery was performed and immunohistochemical staining confirmed the diagnosis of Triton tumor. Patient was referred for further necessary treatments.In cases of mandibular tumors with initial histopathologic findings of sarcoma, uncommon differential diagnosis such as peripheral nerve sheath tumors must be considered as well.

Neurofibromatosis type-1 (NF1), also known as Von Recklinghausen disease, is an autosomal dominant disorder with incidence of one per 4000. Neurofibromas are benign, heterogeneous, peripheral nerve sheath tumors coming up from the connective tissue of peripheral nerve sheaths, particularly the endoneurium. Visceral involvement in disseminated neurofibromatosis is considered rare. Neurofibroma occurs most frequently in the stomach and jejunum, but colon and anorectal canal may also be involved. Gastrointestinal neurofibromas may lead to bleeding, obstruction, intussusception, protein-losing enteropathy and bowel perforation. We encountered a case of diffusely involving the anorectal area by huge neurofibroma, which resulted in pelvic pain with watery diarrhea and urgency.

Malignant peripheral nerve sheath tumors (MPNSTs) are rare soft tissue sarcomas, that impact approximately 0.001% of the population. Individuals with neurofibromatosis type 1 (NF1) have a 10% lifetime risk of developing these tumors, which account for up to 50% of all MPNST cases. A 49-year-old woman with diffuse NF1 was examined for a painful, growing, and hemorrhagic ankle lesion that had existed from the age of two. The mass was excised using Mohs surgery, and the pathology revealed a malignant peripheral nerve sheath tumor. This study presented a case of neurofibromatosis type 1, which was distinguished by a rare extent of lesion involvement throughout the body. The emergence of such a tumor in this condition is infrequent, even according to existing literature, making it a remarkable observation for expert dermatologists.

Malignant peripheral nerve sheath tumor (MPNST), the principle malignancy of peripheral nerve origin, though rare in the general population, occurs with excessive frequency among patients with neurofi bromatosis. This tumor always arises in soft-tissues, usually found in the lower extremities and only 10-12% of all lesions occur in the head and neck region, which makes it a rare entity. The primary intraosseous MPNST is rare and has been reported most frequently in the mandible. This article discusses a case report of MPNST of the left maxilla without a history of benign nerve tissue tumor and the diagnostic diffi culties associated with MPNST.

A 28-year-old man with neurofibromatosis type 1(NF1) presented with a tumor in the sciatic nerve and femoral nerve. The differential diagnosis of malignant peripheral nerve sheath tumor was based on clinical, radiological, and histological evidence. The tumor apparently originated in sciatic nerve at the posterior aspect of the left thigh. The lesion was resected totally without neural damage to the sciatic nerve. The tumor did not recur after 2 years.

Tumors that originate from the nerve sheath comprise diverse groups -perineuroma, neurofibroma and schwannoma. The epithelioid variant of these tumors is uncommon and mostly seen in malignant counterparts. Although this type of morphology is well recognized in peripheral nerve sheath tumors, its presence in the central nerves is rarely reported. Very few cases of nerve sheath tumors have been reported with collagen-rich stroma. Here we report an extremely rare case of nerve sheath tumor with epithelioid morphology and collagen rich stroma. To the best of our knowledge this finding in the spinal cord has not been reported thus far.

Malignant peripheral nerve-sheath tumor (MPNST) is a high-grade malignant tumor of ecto-mesenchymal origin comprising approximately 10% of soft-tissue sarcomas. They tend to occur associated with neurofibromatosis or sporadically. Here we report a MPNST at an extremely rare location and behavior causing disappearance of the entire kidney. Patient evaluation included clinical, biochemical and radiological studies before treatment. Histological study revealed the rare diagnosis. Patient was asymptomatic at six-month follow-up after treatment..

Schwannomas are considered benign soft tissue tumors that originate from Schwann cells. Oral Schwannomas are rare and account for only 1% of all Schwannomas. Cellularschwannoma (CS) is a rare histological variant of schwannoma, characterized by high cellularity and cellular atypia. We present a case of localized growth of palatal mucosa that imitated the features of malignant peripheral nerve sheath tumor (MPNST) on histopathological examination; it was differentiated from MPNST by the correlation of clinical, histopathological, and immunohistochemical features.