Extraaxial primitive neuroectodermal tumor mimicking a vestibular schwannoma: diagnostic and therapeutic difficulties. Report of two cases

Primary Intracranial Ewing Sarcoma With EWSR1-FLI1 Gene Translocation Mimicking a Meningioma and a Multidisciplinary Therapeutic Approach: A Case Report and Systematic Review of Literatures

Ewing sarcoma and peripheral primitive neuroectodermal tumor (ES/pPNET) is an undifferentiated malignant tumor that is most prevalent in children and young adults and often radiologically mimics a meningioma. A 38-year-old female patient visited our hospital with complaints of right-sided tinnitus, right hemiparesis, and imbalance. She underwent preoperative imaging and was subsequently diagnosed as having a meningioma on the petrous ridge. After partial resection, EWSR1-FLI1 gene fusion was confirmed, and she was diagnosed with ES/pPNET. The tumor was successfully treated using a multidisciplinary approach of adjuvant chemo- and radiotherapy. This case is noteworthy because it is an extremely rare case of an intracranial ES/pPNET, and it is worth sharing our clinical experience that the tumor was successfully treated through a multidisciplinary therapeutic approach even though complete resection was not achieved.

Case report: Primary intracranial EWs/PNET in adults: Clinical experience and literature review

Introduction

Adult primary intracranial Ewing sarcomas (EWs)/primitive neuroectodermal tumors (PNETs) are extremely rare, with only 30 patients published before us. The imaging features and treatment strategies of primary intracranial EWs/PNETs are unclear due to its rarity. The aim of this study was to investigate the clinical features, imaging findings, treatment, survival analysis, and prognosis of adult EWs/PNETs, and a systematic review was conducted based on the patient we treated and published literature.

Case description

A 19-year-old male patient suffered from head pain due to an accidental fall on a motorcycle that occurred more than 10 days before going to the hospital, and underwent computed tomography (CT) examination; it was found that the left temporo-occipital fossa was occupied. Magnetic resonance imaging (MRI) was recommended to understand the nature of the lesion, and the result showed that it has a high probability of being a meningioma. He underwent surgical removal of the mass under general anesthesia, and surprisingly, postoperative pathology revealed EWs/PNET. The disease has a high degree of malignancy, and the patient developed multiple metastases throughout the body 5 years after surgery.

Conclusion

Primary intracranial EWs/PNETs in adult patients are rare, of which imaging findings should be considered as one of the differential diagnoses of meningioma, hemangiopericytoma, and malignant triton tumor. Larger solid-cystic masses with septum-like enhancement may be relatively specific imaging findings of intracranial EWs/PNETs. The prognosis of primary adult intracranial EWs/PNETs is poor. Radical tumor resection combined with radiotherapy and chemotherapy is currently the main and possibly the most effective treatment method.

Primary Intracranial Ewing Sarcoma/Peripheral Primitive Neuroectodermal Tumor Mimicking Meningioma: A Case Report and Literature Review

Background: Primary intracranial Ewing sarcoma (ES)/peripheral primitive neuroectodermal tumors (pPNETs) are extremely rare malignancies, which arise in children and adolescents, with only 9 cases reported in patients over 30 years of age. Due to its rarity, MRI features and treatment strategies for primary intracranial ES/pPNETs remain unclear. The purpose of this study was to explore the clinical features, imaging findings, pathological characteristics, different diagnoses, treatment, and prognosis of cerebellar liponeurocytoma in adults.

Case Description: A 55-year-old female was admitted to the hospital with memory decline over 1 month, which aggravated in the last 2 weeks. MRI showed a 4.3 × 6.5 × 3.5 cm heterogeneous large mass in the left frontal lobe with mild peritumoral edema. The mass was successfully removed under neuronavigation and electrophysiological monitoring. The entire mass was removed, and postoperative pathology indicated an ES pPNET diagnosis, with an EWSR1 gene rearrangement. Subsequently, the patient underwent disciplinary radiotherapy.

Conclusion: The diagnosis of primary intracranial ES/pPNETs depends on the comprehensive consideration of histological examination, immunohistochemical analysis, and genetic detection. Gross tumor resection combined with radiotherapy and chemotherapy might be the most beneficial treatment.

Primary Intracranial pPNET/Ewing Sarcoma: Diagnosis, Management, and Prognostic Factors Dilemma-A Systematic Review of the Literature

BACKGROUND

Ewing sarcoma (ES) is a malignant bone tumor that is most commonly observed in the long bones, the pelvis, and the chest. Primary intracranial localization is extremely rare.

OBJECTIVE

In the aim of identifying the prognostic factors of this rare localization, we conducted a systematic review of the literature for patients with primary intracranial peripheral primitive neuroectodermal tumor/ES.

METHODS

A complete MEDLINE search was undertaken for all articles reporting data for primary intracranial peripheral primitive neuroectodermal tumor/ES. We divided the patient population into 2 groups: group I, patients who were free of disease; and group II, patients who died or had uncontrolled disease at the last available follow-up. We conducted a comparative statistical analysis of data between the 2 groups.

RESULTS

A total of 48 patients were included in the review. There were 32 patients in group I and 12 in group II. Fifty percent of tumors in group II and only 16% of tumors in group I were infratentotorial (P = 0.03). Signs of bone involvement were observed in 19% of patients in group I and 54% in group II (P = 0.03). Total removal was accomplished in 29% of patients in group I and in no patients in group II (P = 0.03). Radiotherapy was performed in 73% of patients in group II and 81% in group I (P = 0.43). Chemotherapy was administered in 36% of patients in group II and 74% in group I (P = 0.03).

CONCLUSIONS

Infratentorial localization and the presence of bone involvement were associated with poor prognosis; Surgery seems to be a predictive factor of prognosis; radiotherapy and chemotherapy must be performed whenever the tumor is not totally removed.

Meningeal Ewing Sarcoma/Peripheral PNET: Clinicopathological, Immunohistochemical and FISH study of four cases

Meningeal Ewing Sarcoma (ES)/peripheral primitive neuroectodermal tumor (pPNET) is a rare diagnostically challenging small round cell tumor in the CNS. This study investigates the clinical pathological features of four cases of this tumor from archives of 6 years in our hospital. Patients were within the median age of 21.5 years and male to female ratio was 1:1. The tumors distributed at the supra-tentorial location, posterior fossa and lumbar vertebral canal, usually presenting as the dura-sited nodule or having close connection with the meninges within the cranium or vertebral canal. Histopathologically, small round undifferentiated tumor cells with hypercellularities, scant cytoplasm and inconspicuous nucleoli were observed, although some components such as atypical larger vesicular nuclei, prominent nucleoli of tumor cells, necrotic foci and mesenchymal collagen proliferation forming the lobular structure, were also appreciated. Immunohistochemally, tumor cells displayed membranous positivity of CD99 (4/4), nuclear positivity of FLI-1 (4/4) and NKX2.2 (4/4), negativity of EMA, GFAP and synaptophysin expression. The histochemical PAS staining showed weak positivity in one case. Fluorescence in situ hybridization (FISH) test using EWSR1 (22q12) dual color break apart rearrangement probe showed positive results in two cases. Results suggest that using a panel of immunohistochemical markers, including NKX2.2, CD99, FLI-1, EMA, GFAP and synaptophysin, combined with the supplementary EWSR1 FISH test, helps to define the diagnosis of meningeal ES/pPNET of CNS.

Cerebellopontine angle primitive neuroectodermal tumor mimicking trigeminal schwannoma

BACKGROUND

Primitive neuroectodermal tumors (PNETs) comprise a group of aggressive, poorly differentiated embryonal tumors occurring in central nervous system as well as in peripheral locations. Primary cerebellopontine angle (CPA) PNET is an extremely rare entity. It is important to have knowledge of this pathology and to be able to differentiate it from other commonly occurring CPA tumors, such as vestibular and trigeminal schwannomas. This distinction is essential because of the difference in the overall treatment plan and prognosis.

CASE DESCRIPTION

This report describes a case of a young male presenting with diplopia and numbness of face; magnetic resonance imaging showed a CPA mass. With a provisional diagnosis of trigeminal schwannoma, the patient underwent surgery. Histopathology provided a diagnosis of PNET.

CONCLUSION

We discuss the importance of recognizing this rare condition and how this entity differs from the commonly occurring tumors.

Primary Ewing's sarcoma affecting the central nervous system: a review and proposed prognostic considerations

Ewing's sarcoma (ES) is a part of a larger family of round blue cell tumors, which occasionally manifest as osseous or extraosseous lesions adjacent to or within the central nervous system (CNS). While a large body of literature exists on ES of bone, data are lacking on tumors with cranial or spinal components that affect the CNS. Here, we perform a systematic review of the literature and summarize the best available evidence on diagnosis, treatment and outcomes of ES affecting the CNS with emphasis on the breadth of clinical presentations, diagnostic tools and emerging management options for these rare and challenging lesions. We include a review of known prognostic factors and propose several new considerations for prognostication of ES affecting the CNS.

Ewing's Sarcoma/Peripheral Primitive Neuroectodermal Tumor in the Cerebellopontine Angle : Diagnosis and Treatment

Ewing's sarcoma/primitive neuroectodermal tumor (ES/PNET) is an unusual malignancy with aggressive behavior. ES/PNET in the cerebellopontine angle (CPA) is extremely uncommon, and we report on a rare case here. A 31-year-old man presented with one month history of left facial palsy, hearing loss, swallowing difficulty, and hoarseness. Magnetic resonance images showed a large mass in the left CPA and a small one in the right cerebellar hemisphere. The patient underwent a surgery for the CPA mass lesion, and the pathology was compatible with ES/PNET. Radiation therapy and chemotherapy were administered. In contrast to the initial radiologic findings resembling vestibular schwannoma or meningioma, ES/PNET had several distinct clinical features. A patient with a CPA mass and presenting unusual clinical features should be suspected of having a rare malignancy.

Primary peripheral PNET/Ewing's sarcoma arising in the meninges, confirmed by the presence of the rare translocation t(21;22) (q22;q12)

Peripheral primitive neuroectodermal tumor/Ewing's sarcoma (ES) (pPNET/ES) of intracranial origin are very rare. These tumors are characterized by specific translocations involving a gene on chromosome 22q12, the most common being t(11;22) (q24;q12). We report a case of 37-year-old man with pPNET/ES arising in the meninges and bearing the rare translocation t(21;22) (q22;q12). The tumor was composed of sheets and nests of monotonous small cells with round to oval nuclei, finely dispersed chromatin, small nucleolus and scant cytoplasm. We discuss the importance of the differential diagnosis with central primitive neuroectodermal tumors (cPNET).

A Primary Extraosseous Ewing Sarcoma in the Cerebellopontine Angle of a Child: Review of Relevant Literature and Case Report

BACKGROUND AND IMPORTANCE:

We report the occurrence of a primary intracranial extraosseous Ewing sarcoma/peripheral primitive neuroectodermal tumor (EES/pPNET) in the cerebellopontine angle in a child.

CLINICAL PRESENTATION:

A 10-year-old girl presented with symptoms and signs of an infratentorial space-occupying lesion that was confirmed by magnetic resonance imaging and followed up by subtotal surgical resection. Tumor cells displayed membranous expression of CD99, and one of the typical translocations of EES/pPNET (chromosome 22) was demonstrated by cytogenetic analysis.

CONCLUSION:

The literature regarding the histopathological, molecular, radiological, prognostic, and therapeutic features of intracranial EES/pPNET is reviewed, emphasizing the distinction of this entity from the central PNET. Although exceptionally rare, intracranial EES/pPNET should be considered in the differential diagnosis of lesions in the cerebellopontine angle.

Intracranial peripheral-type primitive neuroectodermal tumor

A 15-year-old man presented with headache. Magnetic resonance (MR) imaging revealed a large extraaxial tumor with cyst at the right frontotemporal region. The solid part of the tumor was homogeneously enhanced on T(1)-weighted MR imaging after injection of gadolinium. Digital subtraction angiography of the external carotid artery revealed sunburst appearance corresponding to the tumor, which was fed by the right middle meningeal artery. His headache worsened and computed tomography revealed enlargement of the tumor and intracystic hemorrhage, so emergent operation was performed. At surgery, the tumor strongly adhered to the dural membrane, and was obviously extraaxial. The tumor and cyst were gross totally removed. The attachment site at the dura mater was resected. Histological examination showed solid growth of small round cells with uniform round nuclei and minimal cytoplasm. Immunohistochemical staining showed the cells were positive for MIC-2 (CD99). The MIB-1 labeling index was 53%. The histological diagnosis was peripheral-type primitive neuroectodermal tumor (pPNET). Following surgery, radiation therapy and chemotherapy were given. Ewing's sarcoma and pPNET form a family of small round cell tumors arising in the bone or soft tissue. MIC-2 is a useful marker in the differential diagnosis. Good prognosis may be attained if complete surgical excision of intracranial pPNET is achieved.

Imaging of cerebellopontine angle lesions: an update. Part 2: intra-axial lesions, skull base lesions that may invade the CPA region, and non-enhancing extra-axial lesions

Computed tomography (CT) and magnetic resonance (MR) imaging reliably demonstrate typical features of vestibular schwannomas or meningiomas in the vast majority of mass lesions responsible for cerebellopontine angle (CPA) syndrome. However, a large variety of unusual lesions can also be encountered in the CPA. Covering the entire spectrum of lesions potentially found in the CPA, these articles explain the pertinent neuroimaging features that radiologists need to know to make clinically relevant diagnoses in these cases, including data from diffusion- and perfusion-weighted imaging or MR spectroscopy, when available. A diagnostic algorithm based on the lesion's site of origin, shape and margins, density, signal intensity and contrast material uptake is also proposed. Non-enhancing extra-axial CPA masses are cystic (epidermoid cyst, arachnoid cyst, neurenteric cyst) or contain fat (dermoid cyst, lipoma). Tumours can also extend into the CPA by extension from the skull base (paraganglioma, chondromatous tumours, chordoma, cholesterol granuloma, endolymphatic sac tumour). Finally, brain stem or ventricular tumours can present with a significant exophytic component in the CPA that may be difficult to differentiate from an extra-axial lesion (lymphoma, hemangioblastoma, choroid plexus papilloma, ependymoma, glioma, medulloblastoma, dysembryoplastic neuroepithelial tumour).