A case report of sinonasal glomangiopericytoma: An important reminder to always collect specimen.

OBJECTIVES: To present a case report of sinonasal glomangiopericytoma (GPC) in a female patient in her thirties and to highlight the importance of collecting pathology specimens even in routine sinus surgery cases. METHODS: A case report detailing the diagnosis of GPC in a female in her thirties, including her initial presentation, treatment, and follow-up, along with a brief review of the literature. RESULTS: Pathology of the collected specimen revealed sinonasal GPC along with chronic rhinosinusitis. Immunohistochemistry was positive for SMA, beta-catenin, and cyclin D1; and negative for STAT6, ERG, pankeratin, SOX10, and S100. CONCLUSION: This diagnosis expands the knowledge around the demographic profile of GPC patients. GPC should be included in the differential diagnosis of sinonasal masses, even in younger patients. The case highlights the importance of collecting the entire pathology specimen in all cases, even of ones that seem routine and benign.

Pediatric upper lip myopericytoma: a case report and comprehensive review.

BACKGROUND: Myopericytoma is a rare spindle cell tumor of mesenchymal origin, typically benign, characterized by concentric proliferation of tumor cells around blood vessels within subcutaneous tissue. It primarily occurs in middle-aged adults and is often located in distal extremities, although cases have been reported in proximal extremities and head-neck regions. However, occurrences within the oral cavity are exceedingly rare. To date, literature reviews have identified only two cases in children under 10 years old and reported only five cases of myopericytoma occurring in the lip region. We provide a comprehensive review and analysis of all documented cases to better understand this condition. CASE PRESENTATION: A 7-year-old girl presented to oral and maxillofacial surgery with the discovery of a painless mass on the inner aspect of the upper lip. The diagnosis of myopericytoma was confirmed by histological examination (HE staining), alcian blue staining, and immunohistochemistry. CONCLUSIONS: Following surgical excision, there were no signs of recurrence at a 3-month follow-up. The pathological diagnosis of myopericytoma is quite challenging, and immunohistochemical testing is necessary.

Conditional survival analysis and dynamic survival prediction for intracranial solitary-fibrous tumor/hemangiopericytoma.

BACKGROUND: As the form of World Health Organization Central Nervous System (WHO CNS) tumor classifications is updated, there is a lack of research on outcomes for intracranial combined solitary-fibrous tumor and hemangiopericytoma (SFT/HPC). This study aimed to explore conditional survival (CS) pattern and develop a survival prediction tool for intracranial SFT/HPC patients. METHODS: Data of intracranial SFT/HPC patients was gathered from the Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute. The patients were split into training and validation groups at a 7:3 ratio for our analysis. CS is defined as the likelihood of surviving for a specified period of time (y years), given that the patient has survived x years after initial diagnosis. Then, we used this definition of CS to analyze the intracranial SFT/HPC patients. The least absolute shrinkage and selection operator (LASSO) regression and best subset regression (BSR) were employed to identify predictive factors. The Multivariate Cox regression analysis was applied to establish a novel CS-based nomogram, and a risk stratification system was developed using this model. RESULTS: From the SEER database, 401 patients who were diagnosed with intracranial SFT/HPC between 2000 and 2019 were identified. Among them, 280 were included in the training group and 121 were included in the internal validation group for analysis. Our study revealed that in intracranial SFT/HPC, 5-year survival rates saw significant improvement ranging from 78% at initial diagnosis to rates of 83%, 87%, 90%, and 95% with each successive year after surviving for 1-4 years. The LASSO regression and BSR identified patient age, tumor behavior, surgery and radiotherapy as predictors of CS-based nomogram development. A risk stratification system was also successfully constructed to facilitate the identification of high-risk patients. CONCLUSION: The CS pattern of intracranial SFT/HPC patients was outlined, revealing a notable improvement in 5-year survival rates after an added period of survival. Our newly-established CS-based nomogram and risk stratification system can provide a real-time dynamic survival estimation and facilitate the identification of high-risk patients, allowing clinicians to better guide treatment decision for these patients.

Establishment and characterization of a patient-derived solitary fibrous tumor/hemangiopericytoma cell line model.

Solitary fibrous tumor/Hemangiopericytoma (SFT/HPC) is a rare subtype of soft tissue sarcoma harboring NAB2-STAT6 gene fusions. Mechanistic studies and therapeutic development on SFT/HPC are impeded by scarcity and lack of system models. In this study, we established and characterized a novel SFT/HPC patient-derived cell line (PDC), SFT-S1, and screened for potential drug candidates that could be repurposed for the treatment of SFT/HPC. Immunohistochemistry profiles of the PDC was consistent with the patient's tumor sample (CD99+/CD34+/desmin-). RNA sequencing, followed by Sanger sequencing confirmed the pathognomonic NAB2exon3-STAT6exon18 fusion in both the PDC and the original tumor. Transcriptomic data showed strong enrichment for oncogenic pathways (epithelial-mesenchymal transition, FGF, EGR1 and TGFß signaling pathways) in the tumor. Whole genome sequencing identified potentially pathogenic somatic variants such as MAGEA10 and ABCA2. Among a panel of 14 targeted agents screened, dasatinib was identified to be the most potent small molecule inhibitor against the PDC (IC50, 473 nM), followed by osimertinib (IC50, 730 nM) and sunitinib (IC50, 1765 nM). Methylation profiling of the tumor suggests that this specific variant of SFT/HPC could lead to genome-wide hypomethylation. In conclusion, we established a novel PDC model of SFT/HPC with comprehensive characterization of its genomic, epigenomic and transcriptomic landscape, which can facilitate future preclinical studies of SFT/HPC, such as in vitro drug screening and in vivo drug testing.

Infantile (congenital) anaplastic intracranial solitary fibrous tumor/hemangiopericytoma-A case report with brief literature review.

Solitary fibrous tumor/hemangiopericytoma (SFT/HPC) is a rare primary central nervous system (CNS) tumor, included in the World Health Organization (WHO) 2016 classification. Very few cases have been described in the literature so far, especially the infantile type. It is a mesenchymal tumor of the fibroblastic type, characterized by the fusion of NAB 2 and STAT 6 genes. A 10-month-old boy presented to our neurosurgery department with complaints of increasing head circumference since 1 month of age. The magnetic resonance imaging (MRI) showed a space-occupying lesion measuring 8.2 cm × 7 cm × 6.9 cm in the fronto-temporo-parietal region with a clinical diagnosis of glioma/atypical teratoid rhabdoid tumor (ATRT). The microscopy revealed a spindle cell tumor arranged in a patternless pattern with variable cellularity, increased mitosis, and areas of coagulative necrosis. The immunohistochemistry showed vimentin, CD 34, STAT6, CD99 positivity whereas Glial fibrillary acidic protein, Epithelial membrane antigen, and S-100 negativity. Hence, a diagnosis of anaplastic SFT/HPC (grade-III) was rendered. The patient improved after gross total resection (GTR). The primary intracranial congenital SFT/HPC are extremely rare, often a clinico-radiologically misdiagnosed entity. Thus, the immunohistochemistry/molecular study in addition to histology is mandatory for accurate diagnosis.

Hemangiopericytoma of the central nervous system: a case report.

Hemangiopericytomas or solitary meningeal fibrous tumors are extremely rare mesenchymal tumors. They represent only 1.6% of all central nervous system tumors, occurring mainly in adults between 40 and 50 years of age with a slight male predominance. We report the observation of a 20-year-old man treated at the Oujda Regional Oncology Center for cerebral hemangiopericytoma, revealed by headaches resistant to usual analgesic treatments without other associated signs. Initial imaging a left temporo-parieto-occipital intraaxial tumor process all responsible for a sub-falcoial and temporal engagement whose appearance first evokes a high-grade glial tumor. The patient received a complete excision whose pathological examination with immunohistochemical study was in favor of a grade III hemangiopericytoma according to the WHO 2016 classification. Therapeutic management with adjuvant radiotherapy was supplemented with a volumetric modulated arc therapy (VMAT) technique at a total dose of 54Gy. We will discuss through this case, the clinical and therapeutic peculiarities by a review of the literature.

Presentation of orbital solitary fibrous tumours.

AIMS: To evaluate presenting features of patients with orbital solitary fibrous tumours (SFTs), based on histological phenotype. METHODS: A retrospective case-note review was performed for demographics and presenting features for patients with orbital SFTs. The tumours were classified as "Group IA" hypocellular SFT phenotype, "Group IB" haemangiopericytoma phenotype and low mitotic activity, and high-grade "Group II" haemangiopericytoma phenotype with high mitotic activity. RESULTS: Sixty-four patients (34 female; 53%) presented at a mean age of 42.2 years (median 38; range 19-82), with Group II patients presenting at an older age (mean 53 years). Median symptom duration was 12 months for Groups IA and IB, compared to 4 months for Group II, the commonest symptoms being proptosis (53%), diplopia (41%), periorbital swelling (31%), and altered vision (19%). Mean LogMAR was 0.17 (median 0.0; range -0.2-4), and 14% had ipsilateral optic neuropathy, with no significant difference between the three groups. Non-axial displacement was noted in 69%, a palpable mass in 45%, and reduced eye movements in 59%; choroidal folds and optic disc swelling were recorded in 12% and 9%. SFTs were mostly extraconal (59%), within the superior and superonasal quadrants (44%), with an average estimated tumour volume of 4.9 ml (median 3.6; range 0.31-14.5 ml). CONCLUSION: SFTs may present with impaired visual function (∼15%), fundal abnormalities (a fifth), globe displacement (two-thirds), and reduced ocular motility (over a half). High-grade tumours tend to present more than a decade later, with a shorter duration of symptoms.

Extra-meningeal solitary fibrous tumor: an evolving entity with chameleonic morphological diversity, a hallmark molecular alteration and unresolved issues in risk stratification assessment.

Solitary fibrous tumor (SFT) is a rare type of mesenchymal lesion with variable clinical presentation in which specific clinicopathologic factors have been related to patient outcome. SFT shares an important morphologic and immunohistochemical overlap with other sarcomas, hence the differential diagnosis is challenging. Although molecular studies provide significant clues, especially in the differential diagnosis with other neoplasms, a thorough hematoxylin and eosin analysis and the integration of phenotypical, clinical, and radiological features remain an essential tool in SFT diagnosis. In this review, we discuss some emerging issues still under debate in SFT.

[Research progress of intraspinal solitary fibrous tumor].

Objective: To review the research progress of intraspinal solitary fibrous tumor (SFT). Methods: The domestic and foreign researches on intraspinal SFT were extensively reviewed and analyzed from four aspects, including disease origin, pathological and radiological characteristics, diagnosis and differential diagnosis, and treatment and prognosis. Results: SFT is an interstitial fibroblastic tumor with a low probability of occurrence in the central nervous system, especially in the spinal canal. In 2016, the World Health Organization (WHO) used the joint diagnostic term "SFT/hemangiopericytoma" according to the pathological characteristics of mesenchymal fibroblasts, which can be divided into three levels according to specific characteristics. The diagnosis process of intraspinal SFT is complex and tedious. It has relatively variable imaging manifestations and specific pathological changes of NAB2-STAT6 fusion gene, which often requires differential diagnosis with neurinoma, meningioma, etc. The treatment of SFT is mainly resection, which can be assisted by radiotherapy to improve the prognosis. Conclusion: Intraspinal SFT is a rare disease. Surgery is still the main treatment. It is recommended to combine preoperative or postoperative radiotherapy. The efficacy of chemotherapy is still unclear. In the future, more studies are expected to establish a systematic diagnosis and treatment strategy for intraspinal SFT.

A Single-Center Retrospective Analysis of Intracranial and Spinal Solitary Fibrous Tumor/Hemangiopericytoma Clinical Outcomes: Sex Association With Aggressiveness.

BACKGROUND: Solitary fibrous tumor/hemangiopericytoma (SFT/HPCT) is a rare tumor characterized by high recurrence rate and metastatic potential, even after surgical resection. We report on the clinical outcomes and risk factors for metastasis and progression-free survival (PFS) of patients diagnosed with SFT/HPCT. METHODS: We retrospectively identified patients with intracranial or spinal SFT/HPCT who underwent surgical resection and/or radiation therapy at our institution between 1995 and 2021. Baseline demographics, tumor characteristics, and outcome data were collected, and factors associated with PFS and metastasis were analyzed. RESULTS: Thirty-four subjects (mean age, 46.4 years; 44% female) with a histopathologically proven diagnosis of SFT/HPCT were included; the median follow-up was 89.7 months. Twenty-two tumors were supratentorial (67%), 6 (18%) were infratentorial, and 5 (15%) were spinal. Eleven patients had documented occurrence of metastasis (32%). Detailed preoperative and postoperative data were available for 25 patients (74%) who received treatment at our institution after their initial diagnosis. Of those, 20 (80%) underwent gross total resection (GTR), and 12 (48%) received either adjuvant or salvage radiotherapy. Univariate analyses revealed that males had a shorter mean PFS compared with females (25 months vs. 78 months; P = 0.01), and that patients who underwent GTR had a longer mean PFS compared with those who underwent subtotal resection (54 months vs. 23 months; P = 0.02). Male sex was the sole risk factor for metastasis (odds ratio, 6.75; 95% confidence interval, 1.19-38.02). CONCLUSIONS: Our data demonstrate a strong association between male sex and the outcomes of shorter PFS and higher risk for metastases. Further research is warranted to understand the clinical characteristics and outcomes of this rare tumor.

Multidisciplinary Treatment of Liver Metastases from Intracranial SFTs/HPCs: A Report of Three Consecutive Cases.

In the 2016 WHO classification of tumors of the central nervous system, hemangiopericytomas (HPCs) and solitary fibrous tumors (SFTs) were integrated into a new entity (SFT/HPC). Metastases to bone, liver, lung, and abdominal cavity are of concern. Only 37 cases of patients with liver metastases due to intracranial SFTs/HPCs have been reported. Herein, we present our experience in the management of patients with liver metastases from intracranial SFTs/HCPs. All consecutive patients who were treated for liver metastases from intracranial SFTs/HPCs from January 2014 to December 2020 were enrolled. Overall, three patients were treated for liver metastasis from SFTs/HPCs with curative intent. Two patients with bilobar metastases at presentation required surgical resection, transarterial embolization, stereotactic radiofrequency ablation (SRFA) and systemic therapy. One patient with a singular right liver lobe metastasis was treated with SRFA alone. This patient shows no evidence of liver metastases 39 months following diagnosis. Of the two patients with bilobar disease, one died 89 months following diagnosis, while one is still alive 73 months following diagnosis. Long-term survival can be achieved using a multimodal treatment concept, including surgery, loco-regional and systemic therapies. Referral to a specialized tertiary cancer center and comprehensive long-term follow-up examinations are essential.

Recurrent meningeal malignant tumor: Assessment of differences in the solitary fibrous tumor/hemangiopericytoma spectrum through a case report.

Solitary fibrous tumors (SFTs) are neoplasms that grow from mesenchymal fusiform cells. In the central nervous system, meninges are the common origin of these neoplasms. Although literature reports mostly SFT as benign neoplasm, malignancy data have been described in recurrences or metastatic lesions. Definitive diagnosis includes immunohistochemical profiles assessing cellular positivity for CD34, vimentin, CD99 and Bcl-2. Recent studies have demonstrated NAB2-STAT6 gene fusion as a distinct molecular feature of SFT with overexpression of the fusion protein NAB2-STAT6 in nuclei of these cells. Since several years, pathologists have grouped SFT and hemangiopericytomas (HPC) as different phenotypes of the same entity although both neoplasms do not share numerous features. This article, based on a case of a recurrent malignant SFT, aims to emphasize differences in the SFT/HPC spectrum due to the diagnostic, therapeutic and prognostic implications.

Cerebral Hemangiopericytoma Manifesting as Epilepsia Partialis Continua: A Case Report.

Cerebral hemangiopericytomas are very rare mesenchymal tumours arising from pericytes surrounding the blood vessels in the brain. Most patients present with headaches, focal neurological findings and focal seizures with or without generalisation. Our patient chiefly complained of an uncontrollable movement of her right hand that was initially fleeting but later became continuous. Her symptoms were initially described as tremors. We found an intracranial tumour as a cause of her symptoms, suspected the tumour to be a meningioma and performed surgical extirpation which resulted in symptom resolution. Histopathology and immunohistochemistry of the excised mass revealed that the tumour was hemangiopericytoma. The patient is being closely monitored for recurrences and metastasis. Hemangiopericytomas are very rare and they rarely result in the abnormal movements of epilepsia partialis continua. Differentiation of the abnormal movements of epilepsia partialis continua from tremors is very important as is the differentiation of the tumour from meningioma. Keywords: case reports; epilepsia partialis continua; hemangiopericytoma; solitary fibrous tumors.

Malignant renal hemangiopericytoma: a case report.

Malignant hemangiopericytoma (HPC) is an uncommon disease first described by Stout and Murray in 1942. Patients with suspected renal HPC on admission sometimes complain of low back pain, hematuria, or hypertension. A combination of histochemical and anatomo-pathologic examinations is necessary to confirm the diagnosis of renal HPC. We report the case of a 41-year-old female patient who had persistent painful nodular lesion at the right lower back and gross hematuria. Based on analyses of clinical symptoms and signs plus radiological a laboratory examination, she was diagnosed with renal cell carcinoma of the right kidney. She subsequently underwent open right radical nephrectomy via transperitoneal approach. The patient was discharged from hospital in good condition on Day 5 of care after surgical intervention. Malignant HPC of the kidney is an uncommon disease that can be diagnosed based on multislice computerized tomography angiography plus histopathological examination using the periodic acid shift method. Management of malignant renal HPC requires radical nephrectomy followed by chemotherapy. This case study provides important preliminary data for further studies of patients with renal HPC in Indonesia.

CD13 is a useful tool in the differential diagnosis of meningiomas with potential biological and prognostic implications.

Meningiomas are common tumors of the central nervous system. Although their histological diagnosis is usually straightforward, their differential diagnosis versus other tumors may be challenging at times. The objective of this study is to assess the diagnostic value of CD13 immunoexpression in the differential diagnosis between meningiomas and their morphological mimics. Immunohistochemical analysis for CD13, epithelial membrane antigen, SOX10, and STAT6 was carried out in a large cohort of primary meningeal tumors comprising 225 meningiomas, 15 schwannomas, and 20 solitary fibrous tumor/hemangiopericytomas. Within the meningioma group, the expression of CD13 and epithelial membrane antigen was distinguished in three categories using a semiquantitative score. Most of meningiomas expressed CD13 (94%) and epithelial membrane antigen (96%) while none of the schwannomas nor of the solitary fibrous tumor/hemangiopericytomas was positive for either the two markers. Diffuse positivity for CD13 and epithelial membrane antigen was more common in low-grade meningiomas than in anaplastic ones, which were also more often negative for such markers, especially for CD13 (32%). CD13 is a helpful immunohistochemical marker for the differential diagnosis of meningiomas and their mimics, achieving in combination with epithelial membrane antigen maximal sensitivity (100%) and showing statistically relevant difference of expression in comparison with both schwannomas (p < 0.0001) and solitary fibrous tumor/hemangiopericytomas (p < 0.0001). Furthermore, loss of CD13 expression could be related to outcome as it is associated with worrisome histological findings, mainly in the setting of anaplastic meningiomas.

Hemangiopericytoma: Conducts and perioperative management of an extent sinonasal tumor in a Jehovah's Witnesses patient - Case report.

BACKGROUND: Hemangiopericytomas (HPCs) are rare tumors derived from mesenchymal cells with pericyte differentiation. About 5% of head and neck HPCs occur in the nasal cavity and paranasal sinuses. Due to its rarity, rich vascularity and variable biological behavior, its management is a challenge in itself. CASE: We report a case of sinonasal HPC in a Jehovah's Witness patient and discuss the obstacles and care related to the restrictions and therapeutic challenges involved in the approach to the patient. The patient was successfully treated by endoscopic endonasal approach with all per-operative care and restrictions being respected and attended. CONCLUSIONS: The management of HPC by itself involves challenges and when associated with other restrictive conditions attention and care are required.

Sino-nasal hemangiopericytoma: a case series and systematic literature review.

BACKGROUND: Hemangiopericytoma is a rare tumor of the sino-nasal tract. Its clinical behavior is controversial. Whereas some describe an indolent course, others consider it to be an aggressive lesion with a tendency toward rapid local recurrence. Here, we describe our experience in the management of sino-nasal hemangiopericytoma (SN-HPC), comparing our experience with the current literature, and evaluating signs and tools to improve diagnosis and treatment. METHODS: All cases of SN-HPC between 2010 and 2020 were extracted and reviewed from our institutional electronic medical records. SN-HPC cases from PubMed and EMBASE between 2010 and 2020 were analyzed in a systematic literature review using the preferred reporting items for systematic review and meta-analysis (PRISMA) guidelines. Data regarding demographics, presentation, diagnosis, treatment, and outcome were collected. RESULTS: We identified four cases of SN-HPC in the nasal cavity in our institution and an additional 53 cases in previous reports. The mean age at the time of diagnosis was 59 years, with a 1.2:1 male to female ratio. SN-HPC mostly appears unilaterally, arising in the ethmoid sinus (42.1%). The most common presenting symptoms were epistaxis (47.3) and nasal obstruction (47.3%). Both computed tomography (CT) and magnetic resonance imaging (MRI) were required for diagnosis and for tailoring the treatment plan. Endoscopic surgical excision was used in 85.9% of the patients, and in 15.7%, an additional preoperative embolization was performed, which was associated with septal necrosis in one patient (2.6%). The recurrence rate was 7%. CONCLUSION: Although previous reports attribute an aggressive tumoral behavior to SN-HPC, our experience and the literature review support a more indolent course with low recurrence rates following complete endoscopic resection. Preoperative embolization can be useful in certain cases, but due to potential complications, it should not be routinely indicated.

[Solitary fibrous tumor/hemangiopericytoma].

Solitary fibrous tumor(SFT)/hemangiopericytoma(HPC)is a rare mesenchymal tumor with propensity for recurrence and metastasis. Although SFT and HPC were initially considered to be distinct entities, the identification of NAB2-STAT6 fusion as a definitive molecular alteration in both tumors has led to their integration into one disease entity, for both meningeal and non-meningeal lesions. This fusion leads to a nuclear relocation of the STAT6 protein and is detectable with immunohistochemistry. STAT6 immunohistochemistry has been shown to have excellent sensitivity and specificity for histological diagnosis. Although these discoveries have improved the diagnosis of SFT/HPC, the association of the NAB2-STAT6 fusion status with phenotype and prognosis remains unclear, and accurate prognostic factors have not been established. This comprehensive review provides current knowledge on the clinical, histological, and molecular characteristics of SFT/HPC.

Clinicopathological analysis of retroperitoneal solitary fibrous tumours: a study of 31 cases.

A solitary fibrous tumour (SFT) is a mesenchymal tumour that exhibits fibroblast differentiation and rarely occurs in the retroperitoneum. The main purpose of this study was to explore the clinical manifestation, histopathological features and biological behaviour of retroperitoneal SFT. From 2011 to 2020, 31 patients were hospitalized and diagnosed with retroperitoneal SFTs. We summarized and analysed the morphological features, immunophenotype, treatment and prognosis. Patients (13 M; 18 F) ranged in age from 25 to 79 years with a mean age of 53.6 years. The main symptoms included an abdominal mass (48.4%) and abdominal discomfort (25.8%). The mean maximum diameter of the tumours was 12.9 cm (range, 4-40 cm). Histopathologically, there were 17 classic cases and 14 hemangiopericytoma-like cases. The tumour cells were positive for STAT6 (96.8%), CD34 (96.8%), CD99 (93.5%) and BCL-2 (90.3%). All patients were treated with complete surgical excision, and 3 of the patients also received chemotherapy. After a median follow up period of 44 months (range, 6 to 107 months), 2 patients died. Patients in the high- or intermediate-risk group were prone to metastasis and/or recurrence. The sites of metastases and/or recurrences involved the liver, bone and pelvis. The Ki-67 labelling index in the high-intermediate risk group (median, 10%) was significantly higher than that in the low-risk group (median, 3%). The retroperitoneal SFT demonstrates an indolent clinical course, and patients from the high- or intermediate-risk group require close follow-up. A Ki-67 labelling index ≥10% may be used as an important reference for prognosis.

Myopericytoma of the Parotid and Molecular Profiling: Report of a Rare Case and Review of the Literature.

Myopericytomas are uncommon tumors defined by their round to spindle shaped cells often arranged in a concentric pattern of perivascular growth. They are typically well-circumscribed, nodular, slow-growing lesions that occur in the soft tissue of the extremities. Here, we present a 30-year-old female with a 2.4 cm myopericytoma occurring in the deep lobe of the parotid gland. The diagnosis was made with detailed histopathologic and immunohistochemical findings and positive identification of the specific mutation for PDGFRß p.Asp666Lys by next generation sequencing (NGS). This is the first case report of a parotid myopericytoma with a genetic testing that shows a particular mutation that has been linked to myopericytomatosis.