Desmoplastic fibroma of the pediatric cranium with CTNNB1 mutation: case report and literature review.

PURPOSE: Desmoplastic fibroma (DF) is an uncommon intermediate bone tumor rarely involving the skull with unidentified pathogenesis. We report the first case of pediatric temporoparietal cranial desmoplastic fibroma (DF) with a CTNNB1 gene mutation and review the previous literature. CASE PRESENTATION: A 3-year-old boy had a firm, painless mass on the right temporoparietal region for 22 months. The cranial CT scan showed isolated osteolytic destruction in the outer plate and diploe of the right temporoparietal bone. Gross total resection of the lesion and cranioplasty were performed. After that, a growing epidural hematoma was observed so another operation was performed to remove the artificial titanium plate. Postoperative pathology indicated a DF diagnosis and molecular pathology suggested a missense mutation in exon 3 of the CTNNB1 gene (c.100G > A,p.Gly34Arg). CONCLUSION: Pediatric cranial DF is rare and easy to be misdiagnosed before operation. For cranial DF, lesion resection can be performed and perioperative management should be strengthened. Mutations in the CTNNB1 gene might be one of the molecular pathologic features of DF.

Poorly differentiated chordoma with loss of SMARCB1/INI1 expression in pediatric patients: A report of two cases and review of the literature.

Identification of loss of SMARCB1/INI1 expression in poorly differentiated (PD) chordoma in pediatric patients suggests that PD chordoma is an entity molecularly distinct from conventional chordoma or atypical teratoid/rhabdoid tumor, which is also characterized by loss of SMARCB1/INI1 expression by inactivating mutation of the SMARCB1/INI gene. So far, around 20 cases of pediatric PD chordoma with loss of SMARCB1/INI1 expression have been reported. Here, we report two cases of pediatric PD chordoma with loss of SMARCB1/INI1 expression, which is very rare among the pediatric chordoma types. Both patients presented clival masses on preoperative MRI. Histologically, both tumors had nonclassic histologic features for conventional chordoma: sheets of large epithelioid to spindle cells with vesicular nuclei and prominent nucleoli. Both cases revealed nuclear expression of brachyury, loss of SMARCB1/INI1 expression and lack of embryonal, neuroectodermal, or epithelial component. One case showed heterozygous loss of EWSR1 gene by break-apart fluorescence in situ hybridization that reflected loss of SMARCB1/INI1 gene. Based on the clival location and histologic findings along with the loss of SMARCB1/INI1 expression and positivity for nuclear brachyury staining, the final pathologic diagnosis for both cases was PD chordoma.

Unusual skull tumors with psammomatoid bodies: a diagnostic challenge.

AIM: We describe a series of three diagnostically challenging, histologically similar fibro-osseous skull masses. METHODS: The cases were identified in our archives among 50,000 neuropathology specimens. A comprehensive review of the histological, immunohistochemical, ultrastructural, and imaging features as well as the clinical outcome was performed. RESULTS: The routine histology was similar in all 3 cases and showed spindle cell proliferations with frequent calcospheres or psammomatoid bodies. There was no evidence of an underlying subdural component. Immunohistochemistry for the meningioma markers EMA and SSTR2A raised the possibility of intraosseous meningioma, as all 3 lesions were convincingly positive for epithelial membrane antigen (EMA) and 1 lesion was convincingly positive for the somatostatin receptor subtype 2A (SSTR2A); weak, questionable positivity for SSTR2 was present in the remaining 2 cases. In addition, electron microscopy was available in 1 case and showed features consistent with meningioma. CONCLUSIONS: Overall, the findings were most consistent with intraosseous meningioma. Primary intraosseous meningiomas are rare lesions that may present a diagnostic challenge. It is important to consider meningiomas in the differential diagnosis, as extradural meningiomas are associated with an increased risk of recurrence and may occasionally undergo malignant transformation.
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AN AGGRESSIVE TEMPORAL BONE SDHC PARAGANGLIOMA ASSOCIATED WITH INCREASED HIF-2α SIGNALING.

OBJECTIVE: To describe a patient with a germline succinate dehydrogenase (SDHC) gene mutation presenting with primary hyperparathyroidism and a large catecholamine-producing temporal bone paraganglioma (PGL). METHODS: Evaluation of a SDHC mutation-positive PGL tumor biology using staining for tyrosine hydroxylase (TH), hypoxia-inducible factors 1α (HIF-1α) and 2α (HIF-2α). RESULTS: A 66-year-old man was noted to have a lytic skull base mass during work-up for his primary hyperparathyroidism. Biochemical evaluation with 24-hour urine catecholamines and metanephrines revealed marked elevation of norepinephrine and normetanephrine. Genetic testing revealed a germline SDHC mutation. A partial excision of skull base tumor was performed, which upon further examination revealed PGL. Immunohistochemistry of skull base PGL demonstrated heavy expression of TH and HIF-2α but reduced expression of HIF-1α. The remaining skull base PGL was treated with adjuvant radiation therapy. The patient's normetanephrine levels significantly decreased after surgery and radiation. CONCLUSION: Here, we report an unusual case of a patient presenting with a germline SDHC mutation-related functional PGL along with concomitant primary hyperparathyroidism. The present case illustrates that overexpression of HIF-2α but not of HIF-1α is linked to the pathogenesis of SDHC mutation-related PGL, and it may be responsible for the aggressive clinical behavior of a usually indolent course of SDHC-related PGLs.

Chromosome 12 long arm rearrangement covering MDM2 and RASAL1 is associated with aggressive craniofacial juvenile ossifying fibroma and extracranial psammomatoid fibro-osseous lesions.

To evaluate the diagnostic value of MDM2 status in craniofacial fibro-osseous lesions, we investigated MDM2 expression by immunohistochemistry and analyzed MDM2 amplification by qPCR in 30 cases of ossifying fibroma (including 13 cases of the juvenile variant) and 17 cases of fibrous dysplasia. Two cases of uncommon extragnathic psammomatoid fibrous dysplasia and a mixed control group of 15 cases of low-grade osteosarcoma and 15 cases of well-differentiated/dedifferentiated liposarcoma were included. MDM2 amplification was found in 33% of ossifying fibromas (peak of 69% for the juvenile variant) and in 12% of fibrous dysplasia, in none of which was MDM2 overexpressed. All control cases exhibited MDM2 amplification and overexpression. To investigate possible polysomy of chromosome 12, we studied RASAL1 amplification, a gene telomeric to MDM2 on the long arm of chromosome 12. RASAL1 amplification was reported in all benign fibro-osseous lesions exhibiting MDM2 amplification but not in controls. Simultaneous amplification of these two genes was significantly higher in juvenile ossifying fibromas compared with fibrous dysplasia (P=0.004), non-juvenile ossifying fibromas (P=0.001), and all other benign craniofacial fibro-osseous lesions combined (P=0.0001). Of the nine cases of juvenile ossifying fibroma exhibiting amplification, three were locally invasive and four were recurrent, suggesting aggressive disease. The two cases of extragnathic psammomatoid fibrous dysplasia also showed MDM2 and RASAL1 amplification with no MDM2 overexpression. This large chromosome 12 rearrangement, spanning MDM2 and RASAL1, is the first recurrent molecular abnormality to be reported in juvenile ossifying fibroma. It may represent both a molecular diagnostic marker and a characteristic of more aggressive forms with a higher risk of recurrence. Finally, the presence of this rearrangement in extragnathic psammomatoid fibro-osseous lesions mimicking ossifying fibromas might reflect a common molecular pathway in their pathogenesis and calls into question the classification of such lesions within fibrous dysplasia.

Benign Fibro-Osseous Lesions of the Craniofacial Area in Children and Adolescents: A Review.

Benign fibro-osseous lesions (BFOL) of the craniofacial area are represented by a variety of morphologic processes that are characterized by pathologic ossifications and calcifications in association with a hypercellular fibroblastic marrow element. The current classification includes neoplasms, developmental dysplastic lesions and inflammatory/reactive processes [5]. The final diagnosis depends on-clinical, radiological and pathological features. The clinico-pathologic features of this heterogeneous group of diseases are presented in this article.

DNA Mutational and Copy Number Variation Profiling of Primary Craniofacial Osteosarcomas by Next-Generation Sequencing.

BACKGROUND: Craniofacial osteosarcomas (CFOS) are uncommon malignant neoplasms of the head and neck with different clinical presentation, biological behavior and prognosis from conventional osteosarcomas of long bones. Very limited genetic data have been published on CFOS. METHODS: In the current study, we performed comprehensive genomic studies in 15 cases of high-grade CFOS by SNP array and targeted next generation sequencing. RESULT: Our study shows high-grade CFOS demonstrate highly complex and heterogenous genomic alterations and harbor frequently mutated tumor suppressor genes TP53, CDKN2A/B, and PTEN, similar to conventional osteosarcomas. Potentially actionable gene amplifications involving CCNE1, AKT2, MET, NTRK1, PDGFRA, KDR, KIT, MAP3K14, FGFR1, and AURKA were seen in 43% of cases. GNAS hotspot activating mutations were also identified in a subset of CFOS cases, with one case representing malignant transformation from fibrous dysplasia, suggesting a role for GNAS mutation in the development of CFOS. CONCLUSION: High-grade CFOS demonstrate highly complex and heterogenous genomic alterations, with amplification involving receptor tyrosine kinase genes, and frequent mutations involving tumor suppressor genes.

Primary Ewing's sarcoma of cranial bones: analysis of ten patients.

OBJECTIVE: Ewing's sarcomas are the second most common bone tumors in children and primary involvement of the cranium is uncommon. We analyzed retrospectively the data of ten patients with this rare subset of disease, who had been treated at our institute since 2005. Our aim was to assess the outcomes, recurrence rates and the selection of appropriate treatment methods. METHODS: The patients were reviewed with respect to their clinical presentations, treatment, and outcomes. Computed tomographic scanning of the brain was performed for all patients. Skeletal surveys with routine radiographs and technetium-99 bone scans to detect extracranial Ewing's sarcomas were performed for all patients. For all ten patients, radical tumor excision was achieved surgically. Chromosomal translocation studies were carried out on paraffin blocks for nine patients, using fluorescence in situ hybridization (FISH) and polymerase chain reaction (PCR). All patients were then subjected to adjuvant multidrug chemotherapy and radiotherapy. The follow-up periods ranged from 2 months to 5 years (mean, 17.6 months). RESULTS: The predominant presenting features were headaches, increased intracranial pressure, scalp swelling and trigeminal nerve involvement. The erosion of dura and intradural extension was noted in eight patients in our series. All nine patients, in whom FSIH and reverse transcriptase PCR (RT-PCR) was done, tested positive for EWS-FLI1(t22:12) translocation. All patients underwent radical excision within safe limits, followed by chemoradiation. Three patients had local recurrences, which were detected within 12 months after surgery. All three of them died within weeks of presentation with recurrence. One patient experienced a recurrence after 30 months. This recurrent tumor was completely excised, and additional chemotherapy was administered. There was a local recurrence again after 18 months that was treated with surgery and chemoradiation, and the patient is still surviving 5 years after the primary surgery. One patient had metastasis at presentation and died within 2 months of surgery. The remaining five seem to have good outcomes, though the follow-ups were not very long. CONCLUSION: The treatment of primary Ewing's sarcoma of the cranium still remains to be radical surgery, aggressive multidrug chemotherapy, and radiotherapy. Neoadjuvant chemotherapy may not work in patients with large intracranial extension due to raised pressure making decompression imperative. The outcome is usually good if there is no early recurrence. Early recurrence, presence of metastasis and extremes of age probably bears a poor outcome. However, a larger series is required to confirm these findings.

Primary Low-Grade B-Cell Lymphoma of Skull With Translocation Between Immunoglobulin and Interferon Regulatory Factor 4 Genes.

Low-grade B-cell lymphoma with immunoglobulin (IG) and interferon regulatory factor 4 (IRF4) gene rearrangement is extremely rare, with only 4 cases being previously reported. In this article, we report one additional case that arises from the skull and review the literature. The patient was a 69-year-old man who presented with recurrent and disabling vertigo and was found to have a 5.0 × 1.7 cm lesion within the left posterior parietal bone. Histological examination revealed a bone lesion with diffuse lymphoid infiltrate comprising of mostly small lymphocytes with scant cytoplasm, slightly irregular nuclei and inconspicuous nucleoli, and scattered larger cells resembling prolymphocytes and paraimmunoblasts. Immunohistochemical studies showed that the neoplastic cells were positive for CD20, CD79a, PAX5, CD23, CD43, BCL-2, BCL-6, MUM-1, LEF-1, and IgM and negative for CD5, CD10, cyclinD1, SOX11, and IgD. Flow cytometric analysis identified CD5 negative and CD10 negative monoclonal B cells with lambda light chain restriction. Fluorescence in situ hybridization analysis revealed del(13q) abnormality, but was negative for IGH/BCL2, IGH/CCND1, and BIRC3/MALT1 translocations. Next-generation sequencing identified IGK-IRF4 rearrangement and BRD4 E1113 del abnormalities. Given a low clinical stage (IE) of the disease, the patient did not receive additional treatments and was free of disease at 1 year after the diagnosis.

Molecular findings in maxillofacial bone tumours and its diagnostic value.

According to the WHO, mesenchymal tumours of the maxillofacial bones are subdivided in benign and malignant maxillofacial bone and cartilage tumours, fibro-osseous and osteochondromatous lesions as well as giant cell lesions and bone cysts. The histology always needs to be evaluated considering also the clinical and radiological context which remains an important cornerstone in the classification of these lesions. Nevertheless, the diagnosis of maxillofacial bone tumours is often challenging for radiologists as well as pathologists, while an accurate diagnosis is essential for adequate clinical decision-making. The integration of new molecular markers in a multidisciplinary diagnostic approach may not only increase the diagnostic accuracy but potentially also identify new druggable targets for precision medicine. The current review provides an overview of the clinicopathological and molecular findings in maxillofacial bone tumours and discusses the diagnostic value of these genetic aberrations.

A Novel COL1A1-CAMTA1 Rearrangement in Cranial Fasciitis.

Cranial fasciitis is an uncommon benign fibroblastic tumor, generally histologically identical to nodular fasciitis. It develops almost exclusively in children. Cranial fasciitis manifests clinically as a painless rapidly growing solitary nodule in the head and neck area, frequently eroding the underlying bone. Thus, this entity is often confused with aggressive lesions such as sarcomas, both clinically and radiologically. Histopathologic examination is essential to differentiate between cranial fasciitis and fibrohistiocytic or even sarcomatous lesions observed in children. In this article, we present a case of cranial fasciitis with intracranial extension in a 2-year-old boy. Although USP6 rearrangement has recently been recognized as a recurring alteration in nodular fasciitis, we present a novel COL1A1-CAMTA1 fusion in this lesion.

Congenital dermoid inclusion cyst over the anterior fontanel in Chinese children.

Congenital dermoid inclusion cyst (CDIC) over the anterior fontanel is a rare and benign tumor. This study reports nine Chinese cases (three females and six males) with CDIC over the anterior fontanel. The clinical manifestations and imaging were analyzed retrospectively. Surgical resection was undertaken in all cases. The diagnosis of CDIC over the anterior fontanel was confirmed by histological examination. The cysts were all noticed soon after birth and enlarged gradually. They were soft, nontender with a sessile base without inflammatory signs and breaking. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed soft tissue mass over the anterior fontanel without intracranial extensions. The histopathological examination displayed stratified squamous epithelium with skin appendages. There were no complications or recurrence after operation during a follow-up for one year. CDIC over the anterior fontanel is a benign tumor. Imaging is recommended preoperatively to aid differential diagnosis. The main management is total excision with good prognosis.

Epithelioid and spindle cell rhabdomyosarcoma with FUS-TFCP2 or EWSR1-TFCP2 fusion: report of two cases.

The WHO Classification of Tumors of Soft Tissue and Bone divides rhabdomyosarcoma (RMS) into alveolar, embryonal, pleomorphic, and spindle cell/sclerosing types. Advances in molecular diagnostics have allowed for further refinement of RMS classification including the identification of new subtypes. Very rare RMS with epithelioid and spindle cell morphology, female predominance, marked osseous predilection, ALK expression, EWSR1/FUS-TFCP2 gene fusions, and highly aggressive clinical behavior have recently been recognized with only 23 cases reported in the English language literature. Herein, we report two additional cases with detailed clinicopathologic description and molecular confirmation. In brief, two young women presented each with a primary bone tumor-one with a frontal bone tumor and another with an osseous pelvic tumor. Both tumors showed epithelioid to spindle cell morphology, ALK expression, and EWSR1/FUS-TFCP2 gene fusions. Both patients died of disease less than 17 months from diagnosis despite administration of multiple lines of aggressive treatment. In addition, we review the literature and discuss differential diagnostic and potential treatment considerations.

Middle Ear and Temporal Bone Nonkeratinizing Squamous Cell Carcinomas With DEK-AFF2 Fusion: An Emerging Entity.

Primary squamous cell carcinomas (SCCs) of the middle ear and temporal bone are rare and usually keratinizing by morphology. Nonkeratinizing, basaloid SCCs arising in this area are exceedingly rare, and, due to the anatomic proximity to the skull base, nasopharynx, and nasal sinuses, the differential diagnosis is broad. Most tumors with squamous differentiation arising in these subsites are either viral-induced (human papillomavirus/Epstein-Barr virus) or rarely may have specific molecular alterations (BRD4-NUT, EWSR1-FLI translocations). Occasional tumors are negative for these findings, and their pathogenesis is unknown. A recently discovered DEK-AFF2 fusion was clinically detected in a series of 2 cases known to the authors. This fusion has been previously reported in the literature in a patient with a base of skull tumor who was an exceptional responder to programmed cell death protein 1 inhibitor therapy. We examine here the histomorphologic and molecular findings of 2 additional cases of an emerging entity. Two male patients were identified. Each had a primary middle ear/temporal bone mass with locally advanced disease. The histology was reviewed, and immunohistochemistry was performed. RNA-based next-generation sequencing was performed for clinical detection of diagnostic or actionable fusions. Both patients had basaloid/nonkeratinizing tumors on biopsy. They were positive for markers of squamous differentiation (HMWK, CK5, and p40). By RNA sequencing, they demonstrated the presence of a DEK-AFF2 fusion and were negative for EWSR1 and NUT translocations. The DEK-AFF2 fusion may define a novel diagnostic category of middle ear and temporal bone nonkeratinizing/basaloid SCCs. This fusion also may represent a potential avenue for immunotherapy in these patients. Further studies are needed to fully explore whether this fusion defines a location-specific clinicopathologic entity.

Endolymphatic sac tumours and von Hippel-Lindau disease - case report, molecular analysis and histopathological characterization.

Endolymphatic sac tumours (ELST) are aggressive papillary tumours of the temporal bone. The name was finally determined after the endolymphatic sac was determined as the site of their origin. They should be considered in patients with tumours eroding the petrous part of the temporal bone, extending to the cerebellopontine angle or other adjacent structures. These very rare tumours in the general population have much higher prevalence in von Hippel-Lindau disease. Hence molecular analysis of the VHL gene should be performed in patients with ELST and their relatives. The purpose of this study is to present a case report, histopathological characterization of endolymphatic sac tumours, their association with von Hippel-Lindau disease and use of molecular analysis.

Intra-Extracranial Primary Clear Cell Sarcoma: The First Report and Review of the Literature.

BACKGROUND: Clear cell sarcoma (CCS) is a rare malignant soft tissue tumor with poor prognosis owing to metastasis and insensitive response to chemotherapy and radiotherapy. METHODS: We first searched PubMed and Embase using the terms "clear cell sarcoma," "malignant melanoma of soft tissue," "head," and "neck." In the 15 articles selected for literature review, only 27% (4/15) of patients were diagnosed with primary CCS of the head. Pathologically, those tumors arose from either the scalp or the superficial temporal fascia, but none invaded the skull and brain. Next, the search was performed in the same database using the terms "clear cell sarcoma," "malignant melanoma of soft tissue," and "bone," and only 24 articles were selected. RESULTS: In the case reported here, a 36-year-old woman was found to have a palpable mass located at the left temporal-occipital region, and surgical finding confirmed the invasion into the skull and the brain. The diagnosis of primary CCS was made because of the detection of t(12;22)(q13;q12) in >50% of tumor cells by fluorescence in situ hybridization, and metastasis to the lymph nodes and lungs was discovered by postoperative positron emission tomography-computed tomography. CONCLUSIONS: To the best of our knowledge, this is the first case of primary central nervous system CCS. Primary CCS may involve the skull and should be one of the differential diagnoses for intra-extracranial communicating tumors. Further research on biological characteristics and molecular targeted therapy of CCS are needed to improve its poor prognosis.

Giant Cell Lesions of the Maxillofacial Skeleton Express RANKL by RNA In Situ Hybridization Regardless of Histologic Pattern.

Maxillofacial central giant cell lesions (CGCLs) are often locally aggressive tumors in young patients that may be histologically very similar to or quite distinct when compared with giant cell tumors (GCTs) of long bones. It has been well established that GCTs express high levels of receptor activator of nuclear factor-kappa B ligand (RANKL) and are amenable to treatment with denosumab. To assess the predictive value of morphology, we evaluated CGCLs with GCT-like or non-GCT-like histology for RANKL expression by RNA in situ hybridization. Tumors were classified by clinical and radiographic criteria as aggressive or nonaggressive and histopathologically as resembling GCT or non-GCT-like. RNA in situ hybridization for RANKL mRNA was performed and scored semiquantitatively based on the magnification at which the signal was first detected. There were 17 patients (M:F=8:9) with a median age of 15 years. Nine patients were children under 18 years of age. In 10 patients, tumors were characterized as GCT-like and in 7, non-GCT-like; 6 occurred in the setting of a known associated syndrome. Of the sporadic tumors, 9/11 (82%) were classified as aggressive. Fifteen of 17 (88%) tumors strongly expressed RANKL (8/9 aggressive, 2/2 nonaggressive; 10/10 GCT-like and 5/7 non-GCT-like). Two patients with clinically aggressive CGCL, GCT-like histology and high tumor RANKL expression were identified as candidates for a trial of denosumab with notable clinical response. CGCLs demonstrate strong and diffuse RANKL mRNA expression in mononuclear stromal cells, regardless of histology or presence of an associated syndrome. Denosumab may be clinically beneficial in aggressive CGCLs.

Endolymphatic sac tumor (aggressive papillary tumor of middle ear and temporal bone): report of two cases with analysis of the VHL gene.

Endolymphatic sac tumor (Heffner tumor) (ELST) is a very rare nonmetastasizing, locally aggressive low-grade adenocarcinoma of endolymphatic sac origin, which is linked to von-Hippel-Lindau disease (VHLD). VHLD is an autosomal dominant disorder characterized by an inherited genetic abnormality of the VHL gene located on the short arm of chromosome 3 (3p26-p25). VHL gene mutations have been shown both in ELSTs associated with VHLD and in sporadic cases. Because of the rarity of ELST, only a small number of cases have been subjected to molecular genetic analysis. We have encountered two patients with ELST, one of whom presented with a medical and family history of VHLD. The second was a sporadic case, the patient having no symptoms of VHLD. The tissues obtained from Heffner tumor and cerebellar hemangioblastoma from the patient with inherited VHLD possess a point mutation in exon 1 of VHL gene. This mutation is a C to T exchange at position 194, resulting in amino acid exchange S65L. No mutation was found in any of the three exons analyzed and in the exon-intron junctions of the VHL gene in the sporadic case.

Prenatal diagnosis of an epignathus associated with a 49,XXXXY karyotype--a case report.

BACKGROUND: Epignathus is a rare form of congenital teratoma, originating from the base of the skull, most commonly the hard palate, or mandible. It has been associated with a poor prognosis due to complications including polyhydramnios and respiratory compromise at birth as a consequence of upper airway obstructions. It is usually not associated with chromosomal aberrations. We present a case of prenatally diagnosed epignathus associated with a gonosomal pentasomy 49,XXXXY. CASE: A 34-year-old gravida 1, para 0 was referred to our unit with a sonographically suspected gastroschisis at 26+6 weeks' gestation. A detailed ultrasound scan revealed a large mixed echogenic mass seen in continuation with the mouth in the midline. Based on the appearance, an epignathus was suspected. No other fetal anomalies were detected. Karyotyping showed a 49,XXXXY karyotype of the fetus. The couple decided to continue the pregnancy after detailed counseling about results and prognosis. A cesarean section was necessary and performed at 29+0 weeks' gestation due to a pathological Doppler and cardiotocogram. Because of the enormous epignathus intubation of the newborn was not possible. A tracheostomy was performed for ventilation and oxygenation, which failed and the newborn died 30 min after birth. CONCLUSION: Prenatal diagnosis by ultrasound has improved perinatal management. This should include assessment of the tumor size and spread in order to establish an accurate prognosis and to anticipate likely problems which are to be encountered during pregnancy or at the time of delivery. To our knowledge, this is the first reported case of a prenatally diagnosed epignathus with a gonosomal pentasomy 49,XXXXY.

Targeted next-generation sequencing of malignant peripheral nerve sheath tumor of the pterygopalatine fossa with intracranial metastatic recurrence.

Malignant peripheral nerve sheath tumor (MPNST) is an uncommon neoplasm that rarely involves the head and neck region. Intracranial MPNSTs unrelated to cranial nerves are highly malignant tumors with poor overall survival, probably because of infiltrating growth into surrounding brain tissue. The pathogenesis of MPNST remains unclear. There are no conclusive explanations for the mechanisms underlying the initiation, progression, and metastasis of MPNST. In this paper, we describe a case of MPNST in the pterygopalatine fossa with intracranial metastatic recurrence and review related literatures. Meanwhile, targeted next-generation sequencing (NGS) revealed the presence of both a beta-catenin (CTNNB1) missense mutation p.Ser33Phe and a mediator complex subunit 12 (MED12) frameshift mutation p.Tyr1278fs in the recurrent intracranial tumor. Therapies that target CTNNB1 mutation, MED12 mutation, CTNNB1 activation, or Wnt pathway activation are worth future studying.