Primary peripheral primitive neuroectodermal tumors of the spinal cord: report of two cases and review of the literature

Primary Ewing sarcoma/peripheral primitive neuroectodermal tumors in the cranial bone and mobile spine: what is the difference?

BACKGROUND

Primary Ewing sarcoma (ES)/peripheral primitive neuroectodermal tumors (pPNETs) are aggressive bone tumors that rarely occur in the axial skeleton, including the cranial bone and mobile spine. The purpose of this study was to investigate whether there were any differences in patient characteristics, treatment strategies, and outcomes between patients with ES/pPNETs of the cranial bone and those with ES/pPNETs of the mobile spine.

METHODS

A retrospective study was performed on 33 patients with ES/pPNETs who had been surgically treated and pathologically confirmed at our institution between 2010 and 2020. Patient characteristics were compared using Fisher exact tests or independent t tests. Survival rates were estimated via Kaplan-Meier survival analysis and compared using log-rank tests.

RESULTS

Thirteen patients had ES/pPNETs of the cranial bone (39.4%), while 20 patients had ES/pPNETs of the mobile spine (60.6%). Patients with ES/pPNETs of the cranial bone had a younger mean age (14.8 vs 22.6 years; p = 0.047) and longer mean disease duration (2.5 vs 1.9 months; p = 0.008) compared with those of patients with ES/pPNETs of the mobile spine. Kaplan-Meier analysis showed that gross total resection (GTR) and radiotherapy resulted in a longer median survival time. The overall survival rates and progression-free survival rates of patients with ES/pPNETs of the cranial bone versus those of the mobile spine were not significantly different (p = 0.386 and p = 0.368, respectively).

CONCLUSIONS

Patients with ES/pPNETs of the cranial bone were younger compared to patients with ES/pPNETs of the mobile spine. There was no significant difference in the prognosis of patients with ES/pPNETs of the cranial bone versus those of the mobile spine. Taken together, our findings suggest that GTR and radiotherapy offer the best prognosis for improved long-term survival.

Comparative analysis of magnetic resonance imaging and pathological findings of microcystic meningioma and meningeal Ewing sarcoma/peripheral primitive neuroectodermal tumors

Microcystic meningiomas (MCMs) and meningeal Ewing sarcoma/peripheral primitive neuroectodermal tumours (pPNETs) are difficult to differentiate because of the similarity in their image manifestation on magnetic resonance imaging (MRI). Differential diagnosis of these two tumours before surgery could contribute to ameliorating clinical decision-making, and predicting prognosis. Here, we aimed to comparatively analyse the difference between MRI and pathological findings of these two tumours. Thirteen cases of MCM and eleven cases of meningeal Ewing sarcoma/pPNET confirmed through pathology were analysed retrospectively. The imaging features of the two tumours were statistically analysed using the Chi square test. The average age of patients with MCM and meningeal Ewing sarcoma/pPNET was 47 ± 18.4 years and 20 ± 13.2 years, respectively. Features of MRI, including tumour morphology, dural tail sign, bony destruction, and distant metastasis, were significantly different between the two tumours (p < 0.001). T1-weighted (T1W) signal and enhanced features resulted in a p value of < 0.05. There were no significant differences in the T2-weighted (T2W) signal and peri-tumoural oedema (p > 0.05). MCM immunohistochemistry showed that all the cases were positive for vimentin (Vim), epithelial membrane antigen (EMA), and the ki-67 index was less than 5%, while all the cases of meningeal Ewing sarcoma/pPNET were positive for Vim and CD99, and the ki-67 index was more than 30%. MRI imaging features of MCMs and meningeal Ewing sarcoma/pPNETs were different. Accurate preoperative diagnosis of these two tumours is helpful in implementing a clinical surgical plan and further management. Moreover, imaging combined with pathology can explain the imaging characteristics better.

Primary Primitive Neuroectodermal Tumor of the Spine With t(11;22): Report of 3 Cases and Review of Literature

Intradural extramedullary peripheral primitive neuroectodermal tumor (pPNET) with t(11;22) is a rare clinical finding in the pediatric population with few published cases in the literature. The authors report 3 cases of intradural primary pPNET and discuss the clinical presentation, treatment, and survival of the patients. Clinicians should be vigilant in considering pPNET in the differential diagnosis of extradural masses. The authors also compare the clinical course and outcome of therapy with primary PNET of the central nervous system and Ewing sarcoma family of tumors. In addition, this report highlights the risk for leptomeningeal dissemination at recurrence and discusses the importance of central nervous system-targeted therapy for durable disease control.

Analysis of Clinical, Imaging, and Pathologic Features of 36 Patients with Primary Intraspinal Primitive Neuroectodermal Tumors: A Case Series and Literature Review

BACKGROUND AND STUDY AIMS

 Primary intraspinal primitive neuroectodermal tumors (PNETs) account for ∼0.4% of all intraspinal tumors, but information about these tumors in the medical literature is limited to single case reports. We report four cases of primary intraspinal PNETs and present a systematic literature review of the reported cases.

MATERIALS AND METHODS

 We retrospectively reviewed and analyzed the clinical data of 4 patients with primary intraspinal PNETs who underwent neurosurgical treatment at our clinic between January 2013 and January 2020, and of 32 cases reported in the literature.

RESULTS

 The female-to-male ratio was 2.6:1. The mean patient age was 21.42 ± 15.76 years (range: 1-60 years), and patients <36 years of age accounted for 83.30% of the study cohort. Progressive limb weakness and numbness were the chief symptoms (accounting for ∼55.6%). The mean complaint duration was 0.89 ± 0.66 months for males and 2.72 ± 3.82 months for females (p = 0.028). Epidural (41.7%) was the most common site, and thoracic (47.3%) was the most frequent location. Most PNETs were peripheral, and magnetic resonance imaging (MRI) appearance was isointense or mildly hypointense on T1-weighted images and hyperintense on T2-weighted images. Homogeneous contrast enhancement was observed. The 1-year survival rate of patients who underwent chemoradiation after total or subtotal lesion resection was better compared with patients who did not undergo chemotherapy, radiotherapy, or total or subtotal resection. The modality of treatment was associated with survival time (p = 0.007).

CONCLUSION

 Primary intraspinal PNETs mainly occur in young people with a female preponderance. In patients with a rapid loss of lower limb muscle strength and large intraspinal lesions on MRI, PNETs should be considered. Surgical resection and adjuvant radio chemotherapy are key prognostic factors.

Long-term outcomes of surgical resection with or without adjuvant therapy for treatment of primary spinal peripheral primitive neuroectodermal tumors

OBJECTIVE

We sought to assess the use of surgical treatment, the effect of postoperative adjuvant therapy, and the prognostic factors for survival of patients with primary spinal peripheral primitive neuroectodermal tumors (pPNETs).

PATIENTS AND METHODS

The clinical data of 24 patients, who had been surgically treated from April 2003 to February 2018 and in whom immunohistochemical staining results had confirmed the diagnosis of primary spinal pPNETs, were retrospectively analyzed. To analyze the factors related to prognosis, the Kaplan-Meier method was used for univariate analysis, the log-rank method was used to test the significance of difference, and multivariate analysis was performed using Cox regression.

RESULTS

The overall 1-year, 2-year, and 5-year survival rates were 73.2%, 48.1%, and 12.0%, respectively. The median survival time (MST) of all patients was 21 months. Univariate analysis showed that the extent of tumor resection, adjuvant radiotherapy, and chemotherapy were the factors influencing patient prognosis after surgery (all P < 0.05); sex, age, tumor location, and preoperative Karnofsky performance scale (KPS) scores were not the influential factors for prognosis of patients after surgery (all P > 0.05). Multivariate analysis showed that gross total resection (GTR) of tumors and adjuvant radiotherapy were independent factors influencing the prognosis of patients with pPNETs (all P < 0.05).

CONCLUSIONS

Primary spinal pPNETs are extremely rare, and they have a poor prognosis. Microsurgical GTR of the tumor is the preferred method of treatment. Radiotherapy plays an important role in improving the prognosis of patients with pPNETs. GTR combined with radiotherapy and chemotherapy may be the best treatment modality.

Comparison of Primary Spinal Central and Peripheral Primitive Neuroectodermal Tumors in Clinical and Imaging Characteristics and Long-Term Outcome

OBJECTIVE

Primary spinal primitive neuroectodermal tumors are extremely rare entities. The purpose of this study was to analyze the differences in clinical and imaging characteristics and outcomes between primary spinal central PNETs (cPNETs) and peripheral PNETs (pPNETs).

METHODS

There were 25 consecutive patients with primary spinal primitive neuroectodermal tumors enrolled. The diagnosis was cPNET in 6 patients with negative CD99 expression and pPNET in 19 patients with positive CD99 expression. Gross total resection (GTR) was achieved in 12 patients, subtotal resection was performed in 9 patients, and partial resection was performed in 4 patients. Postoperative chemotherapy was given to 14 patients, and radiotherapy was given to 16 patients.

RESULTS

The age at diagnosis was significantly younger in the cPNET group (mean 12.8 years) compared with the pPNET group (mean 22.5 years) (P = 0.040); the 2 pathologies did not show a significant difference in prognosis. GTR (P = 0.041), radiotherapy (P = 0.008), and GTR with radiotherapy (P = 0.009) were significant factors leading to a higher 2-year survival rate. Kaplan-Meier analysis showed that radiotherapy (P < 0.001) and GTR with radiotherapy (P = 0.040) resulted in a longer median survival time. Patients who underwent GTR, chemotherapy, and radiotherapy all together had the highest 1-year (100.0%) and 2-year (71.4%) survival rates and the longest median survival time (32 months).

CONCLUSIONS

Patients with spinal cPNETs were younger compared with patients with pPNETs. The prognosis of spinal cPNETs and pPNETs was poor with no significant difference between the entities. The most beneficial treatment modality is GTR combined with adjuvant radiotherapy and chemotherapy.

Clinical presentation and long-term outcome of primary spinal peripheral primitive neuroectodermal tumors

Primary spinal peripheral primitive neuroectodermal tumors (pPNETs) are extremely rare entities that predominantly occur in children and young adults. Few studies have reported more than three cases. There are no current optimum treatment strategies due to the paucity of data. Here, we present 13 patients (nine females and four males) with primary intraspinal pPNETs who were surgically treated from April 2008 to February 2014. Histopathologic findings revealed the expression of CD99 in all cases. Limb weakness was the most common initial symptom (11/13, 85 %). The tumors were located mainly at the cervical level (6/13, 46 %) and in the epidural space (10/13, 77 %). The radiological diagnosis was neurinoma or meningioma in most cases (10/13, 77 %). Gross total resection was achieved in 77 % (10/13) of patients. During a mean follow-up of 25.5 months, local relapse occurred in 8 (61.5 %) patients and distant metastases occurred in 8 (61.5 %) patients. The overall 1-year survival rate was 77 % (10/13), and the overall 2-year survival rate was 54 % (7/13). The 2-year survival rate was 57.1 % in patients with adjuvant chemotherapy and 50 % in those without chemotherapy. Gross total resection and adjuvant radiotherapy with or without chemotherapy demonstrated a longer survival period (1-year survival rate: 100 %; 2-year survival rate: 86 %). Our data showed that primary spinal pPNETs are extremely rare and aggressive tumors with a poor prognosis. Radical resection is advocated. Gross total resection combined with adjuvant radiation may help to significantly improve patient survival period. Chemotherapy may also help to slightly prolong patient life.

Spinal primitive neuroectodermal tumor mimicking as chronic inflammatory demyelination polyneuropathy: a case report and review of literature

We report a young boy who presented with progressive weakness of lower extremities associated with areflexia and abnormal electrophysiological findings initially suggestive of chronic inflammatory demyelinating polyneuropathy. Initial lumbosacral spinal magnetic resonance imaging (MRI) showed thickened descending spinal nerve roots only. Immunomodulating therapy was given but with limited clinical response. Repeated spine magnetic resonance imaging showed cauda equina and also new spinal cord extramedullary contrast enhancement. The initial extensive investigations including open biopsy did not point to any specific diagnosis. Only through pursuing a repeated biopsy, the diagnosis of the spinal peripheral primitive neuroectodermal tumor was confirmed. This case highlights the diagnostic challenges of the spinal peripheral primitive neuroectodermal tumor that could have an initial chronic inflammatory demyelinating polyneuropathy-like presentation. The literature review confirms that this is a rare condition and cauda equina origin has only been reported in adults and teenagers, and this is the first reported case in a young child.

The imaging features of meningeal Ewing sarcoma/peripheral primitive neuroectodermal tumours (pPNETs)

OBJECTIVE

To explore the imaging features of meningeal Ewing sarcoma/peripheral primitive neuroectodermal tumours (pPNETs).

METHODS

The imaging features and pathological characteristics of eight cases of surgically and pathologically confirmed Ewing sarcoma/pPNET were analysed retrospectively in light of recent literature on the disease.

RESULTS

The peak age was between 10 and 20 years. The lesions tended to be spindle shaped and dural based, usually widely so. CT showed that the lesions had slightly uneven high density in five cases and iso-low mixed density in three cases; marked heterogeneous enhancement was seen in all cases after contrast injection. MRI of the lesions showed varying proportions of isointense and hypointense signal in all cases on unenhanced T1 weighted imaging and varying proportions of isointense and hyperintense signal on T2 weighted imaging. After contrast injection, marked heterogeneous enhancement was seen in all cases; three cases showed a short and nodular dural tail and five cases showed adjacent skull erosion and osteolysis. Pathological results included high cell density, haemorrhage and necrosis. The cells resembled lymphocytes and spindle cells with transparent cytoplasm. CD99 and vimentin were expressed by all tumour cells.

CONCLUSION

Features of meningeal Ewing sarcoma/pPNETs include peak incidence at 10-20 years of age, a broad connection to the meninges, a thick dural tail involved with tumour, skull and scalp erosion and early metastasis. Necrosis and cystic changes are the common histological findings.

ADVANCES IN KNOWLEDGE

The imaging features of meningeal Ewing sarcoma/pPNETs have not been reported. The study helps to identify meningeal Ewing sarcoma/pPNETs and meningioma.

Primary spinal primitive neuroectodermal tumour: report of two cases mimicking neurofibroma and review of the literature

Primary spinal primitive neuroectodermal tumours (PNETs) are a rare entity. Most of them occur in children and young adults. To date, 47 cases of primary spinal PNET have been reported in the literature. We present two cases of primary spinal PNET. In both cases, the tumours were thoracic extradural ones with intrathoracic extension through intervertebral foramina resembling neurofibroma. These tumours are highly aggressive with rapid growth as evidenced by the short history in both of our cases. Both cases underwent gross total removal of the intraspinal and thoracic components. Postoperatively, both patients underwent cranio-spinal radiotherapy. A review of the literature shows that the overall prognosis of PNETs of the spinal cord is very poor even with adequate surgery, radiotherapy and chemotherapy. One patient died after 4 months and the other one is still alive 8 months after surgery, radiotherapy and chemotherapy.

Review of spinal neuroectodermal tumor

Primary spinal primitive neuroectodermal tumors (PNETs) are rare tumors. Most of these tumors occur in children and young adults. To date, 47 cases of primary spinal PNET have been reported in the literature. These tumors are highly aggressive with rapid growth. Review of the literature shows that the overall prognosis of PNETs of spinal cord is very poor even with adequate surgery, radiotherapy and chemotherapy. All the cases reported to date are reviewed in terms of surgical treatment, adjuvant therapy and outcome and the experience with two of these cases are described. Both cases were thoracic extradural ones with intrathoracic extension through intervertebral foramina resembling neurofibroma. Both cases underwent gross total removal of intraspinal and thoracic component. Post-operatively both underwent cranio-spinal radiotherapy. One patient died after a post-operative period of 4 months and the other one is still alive 8 months after surgery, radiotherapy and chemotherapy.

Primary spinal extradural Ewing's sarcoma (primitive neuroectodermal tumor): Report of a case and meta-analysis of the reported cases in the literature

Background:

Primary spinal primitive neuroectodermal tumors (PNET) and/or spinal extraskeletal Ewing's sarcoma family tumors (ESET) are rare lesions appearing in the spinal extradural space. One hundred forty-one primary spinal PNETs, including 29 intramedullary lesions, have been reported in the literature. Encountering a case of primary epidural EES/peripheral PNET (pPNET) in sacral level, which is the fifth one occurring at this level in the literature, we have tried to conduct a meta-analysis of the reported cases.

Case Description:

A 44-year-old lady with epidural EES/pPNET is reported here. She was once operated for L5/S1 herniated disc, which did not ameliorate her symptoms. The clinical, imaging, surgical, and histopathologic characteristics of our case are presented and wide search of the literature is also done. All the reports were level 3 or less evidences and most of the series had missing parts. 106 cases of primary intraspinal (extradural/extramedullary-intradural) EES/pPNET and 29 cases of primary intramedullary PNET (CNS-PNET) have been reported in the literature. The most common clinical presentation in both entities was muscle weakness proportionate to the tumor location. Distant metastasis occurred in 38 of 99 (38%) cases of primary intraspinal EES/pPNET, while the rate of metastasis was 48% in patients with PNETs occurring in the intramedullary region (P > 0.05). One-year survival rate of the patients who underwent chemo-radiation after total or subtotal resection was better than those who did not receive chemotherapy or radiotherapy, or did not have total or subtotal resection. However, this difference was not repeated in 2-year survival rate in any of the tumor groups.

Conclusion:

It seems that total or subtotal removal of the tumor and adjuvant chemo- and radiation therapy can improve the outcome in these patients.

Intraspinal primitive neuroectodermal tumor in a man with neurofibromatosis type 1: Case report and review of the literature

BACKGROUND

The occurrence of primitive neuroectodermal tumors (PNET) in patients with neurofibromatosis type 1 (NF1) has only been reported in two other cases in English-Language literature. Owing to the rarity of intraspinal PNET and the extremely high gene mutation variability in NF1, there is currently no conclusive evidence to suggest that PNET is associated with NF1. Here, we report a case of intradural PNET in a patient with NF1.

CASE DESCRIPTION

A 27-year-old male underwent a C1-C3 laminectomy for resection of an intramedullary mass. Histopathology and immunohistopathology analysis was performed. Microscopic examination and immunohistochemical staining indicated the mass was a primitive neuroectodermal tumor. Within 1 month after tumor resection, the patient developed leptomeningeal carcinomatosis. The patient was not a candidate for radiation therapy but underwent palliative systemic chemotherapy. He subsequently developed neutropenia and died 3 months after tumor resection.

CONCLUSION

To our knowledge, this is the first reported intraspinal PNET associated with NF1. Genetic analysis of CNS PNETs suggests a possible correlation, but larger case series are needed to support this theory.

Intraspinal Ewing's sarcoma/primitive neuroectodermal tumors

Intraspinal Ewing's sarcoma (ES) and primitive neuroectodermal tumors (PNET) are very rare, and the characteristics and prognoses of the disease remain unclear. We present an illustrative patient with an intradural, extramedullary PNET arising within the cervical spinal canal, with clinical and radiological manifestations of leptomeningeal spread, and review the reports of a further 77 patients with intraspinal ES/PNET. Cox regression analyses showed that tumor location (extradural, intradural) (p=0.002, RR=4.217, 95% confidence interval [CI] 1.668-10.664) and spinal segment location (cervical, thoracic, lumbar, or sacral) (p=0.017, RR=2.040, 95% CI 1.133-3.673) were independent factors in the prognosis of intraspinal ES/PNET. We concluded that a peripheral PNET may originate within the spinal canal and exhibit leptomeningeal spread similar to that seen in central PNET, and that a patient with an intradural ES/PNET high in the spinal canal is more likely to have a poor prognosis.

Primitive neuroectodermal tumors of the spine: a comprehensive review with illustrative clinical cases

Primary spinal primitive neuroectodermal tumors (PNETs) are uncommon malignancies that are increasingly reported in the literature. Spinal PNETs, like their cranial counterparts, are aggressive tumors and patients with these tumors typically have short survival times despite maximal surgery, chemotherapy, and radiation. Because no standard management guidelines exist for treating these tumors, a multitude of therapeutic strategies have been employed with varying success. In this study the authors perform a comprehensive review of the literature on primary spinal PNETs and provide 2 new cases that highlight the salient features of their clinical management.

Primary central nervous system primitive neuroectodermal tumors (CNS-PNETs) of the spinal cord in children: four cases from the German HIT database with a critical review of the literature

Approximately 30-50% of patients with intracranial primitive neuroectodermal tumors (PNETs) of the central nervous system (CNS) develop spinal metastases. In contrast, primary spinal CNS-PNETs are extremely uncommon. The database and study records of the German/Austrian brain tumor trials HIT 91, HIT SKK 92, and HIT 2000 were retrospectively reviewed to describe clinical features, treatment modalities, and outcome of children with primary CNS-PNETs of the spinal cord who were registered as observational patients. Out of 1,248 patients with medulloblastomas or CNS-PNETs registered in the HIT database four patients (female, n = 3) with primary CNS-PNETs of the spinal cord were identified. Age at diagnosis was 10, 16, 23, and 174 months. Location of primary tumors was medulla oblongata-T3, C2-T1, T10-L2, T7-T10. Two patients had metastatic disease at diagnosis. Complete and incomplete resection was performed in one patient each, whereas two patients underwent a biopsy only. Two patients received chemotherapy only, in accordance with the HIT 91 trial (sandwich chemotherapy arm). They developed disease progression and died six months after diagnosis. One patient was given chemotherapy in accordance with the HIT 2000 trial followed by craniospinal radiotherapy and four courses of maintenance chemotherapy. The patient is in complete remission almost four years after diagnosis. The fourth patient developed disease progression while receiving induction chemotherapy. Hence, chemotherapy was switched to a modified Head Start protocol. After three cycles he underwent double autologous stem cell transplantation and craniospinal irradiation. Forty months after diagnosis the patient is alive and well, but surveillance MRIs still show nodular enhancing lesions in the area of the primary tumor and intracranial meningeal enhancement. Primary CNS-PNETs of the spinal cord probably require multimodal treatment including radiotherapy to achieve sustained tumor control.

Primary epidural peripheral primitive neuroectodermal tumor of the thoracic spine

A 25-year-old male patient presented with an extremely rare primary spinal peripheral primitive neuroectodermal tumor (pPNET) manifesting as acutely progressive paraparesis and back pain. Neuroimaging and intraoperative examination showed that the tumor was confined to the epidural space of the thoracic spine. The patient was treated successfully by gross total resection of the tumor followed by chemotherapy and local radiotherapy. The present case illustrates the unexpected occurrence and important differential diagnosis of primary epidural pPNET of the thoracic spine in young patients presenting with progressive paraparesis and back pain.

Peripheral Primitive Neuroectodermal Tumour (pPNET) in the cervical spine

Primary spinal primitive neuroectodermal tumours are rare. We present a 45-year-old man with a peripheral primitive neuroectodermal tumour arising in the cervical spine. We believe this to be the first report of this type of tumour in the cervical spine.

Dumbbell-shaped peripheral primitive neuroectodermal tumor of the spine--case report and review of the literature

Primary spinal peripheral primitive neuroectodermal tumors (pPNETs) are extremely rare. Here, we present a case study of a 29-year-old male with a dumbbell-shaped pPNET at the T9-10 spine level, including details of his examination, surgical procedures applied, histological and genetic findings, and his subsequent treatment. We discuss the clinical course, the pathology and treatment for this disease, the surgical approach to thoracic dumbbell tumors and we review the literature. To our knowledge, this is the first report of a case of a dumbbell-shaped intradural and spinal peripheral PNET.

Primary primitive neuroectodermal tumor of the lumbar extradural space

Primary spinal primitive neuroectodermal tumors (PNETs) of the extradural space are very rare; only 10 cases have been reported in the English language literature. The histopathological diagnosis of primary spinal PNETs has been discussed for many years. These tumors have a rapidly progressive course, and there is no current consensus on the optimal therapeutic approach for these patients. The authors present a case of primary PNET located in the lumbar extradural space in a 13-year-old girl and report the clinical, radiological, histopathological, and surgical findings. They compare their findings with those from the other 10 cases reported in the literature and review relevant literature.