Malignant peripheral nerve sheath tumors (malignant schwannomas) in children

Survival outcomes of malignant peripheral nerve sheath tumors (MPNSTs) with and without neurofibromatosis type I (NF1): a meta-analysis

INTRODUCTION

Malignant peripheral nerve sheath tumors (MPNSTs) are malignancies that demonstrate nerve sheath differentiation in the peripheral nervous system. They can occur sporadically or be associated with neurofibromatosis type 1 (NF1), an autosomal dominant neurocutaneous disorder, with up to 13% of patients developing MPNSTs in their lifetimes. Previous studies have suggested conflicting findings regarding the prognosis of NF1 for patients with MPNSTs. The elucidation of NF1 as an independent prognostic factor on mortality has implications for clinical management. We aim to investigate the role of NF1 status as an independent prognostic factor of overall survival (OS) and disease-specific survival (DSS) in MPNSTs.

METHODS

An electronic literature search of PubMed and MEDLINE was performed on studies reporting OS or DSS outcomes of MPNSTs with and without NF1. A grey literature search by reviewing bibliographies of included studies and review articles was performed to find pertinent studies. Data was extracted and assessed in accordance with the PRISMA guidelines. A meta-analysis was performed to calculate hazard ratios (HRs) using a random-effects model. The primary and secondary outcomes were all-cause and disease-specific mortality, respectively, with NF1 as an independent prognostic factor of interest.

RESULTS

A total of 59 retrospective studies involving 3602 patients fulfilled the inclusion criteria for OS analysis, and 23 studies involving 704 MPNST patients were included to evaluate DSS outcomes. There was a significant increase in the hazard of all-cause mortality (HR 1.63, 95% CI 1.45 to 1.84) and disease-specific mortality (HR 1.52, 95% CI 1.24 to 1.88) among NF1 as compared to sporadic cases. Subgroup analyses and meta-regression showed that this result was consistent regardless of the quality of the study and year of publication.

CONCLUSION

NF1 is associated with a substantially higher risk of all-cause and disease-specific mortality. This finding suggests that closer surveillance is required for NF1 patients at risk of developing MPNSTs.

Intraosseous malignant peripheral nerve sheath tumor at the frontal bone in a child: a rare cause of proptosis

We report a nine-year-old male having malignant peripheral nerve sheath tumor (MPNST) of the frontal bone, represented with a twelve-month history of ptosis and proptosis in his right eye and enlarged rapidly in the last three months. Except for slight numbness at his one-third of the right forehead, he had no neurological deficit. The patient's both eyes were having normal eye movements, and he had no visual acuity or field loss. After surgery, we observed the patient with no recurrence for 4 years.

Malignant peripheral nerve sheath tumor in children: A clinicopathologic and molecular study with parallels to the adult counterpart

Malignant peripheral nerve sheath tumors (MPNST) are aggressive neoplasms, arising either sporadically, in the setting of neurofibromatosis type I (NF1) or post radiation. Most MPNST occur in adults and their pathogenesis is driven by the loss of function mutations in the PRC2 complex, regardless of their clinical presentation. In contrast, pediatric MPNST are rare and their pathogenesis has not been elucidated. In this study, we investigate a large cohort of 64 MPNSTs arising in children and young adults (younger than the age of 20 years) to better define their clinicopathologic and molecular features. Sixteen (25%) cases were investigated by MSK-IMPACT, a targeted NGS panel of 505 cancer genes. Most patients (80%) were aged 11-20 years. A history of NF1 was established in half of the cases. Mean tumor size was 8.5 cm. The most common locations included the extremities (34%) and abdomen/pelvis (27%). Histologically, 89% of high-grade MPNST showed conventional features, while the remaining three cases showed a predominant epithelioid phenotype. Heterologous differentiation occurred in 25% of high grade cases, with half showing rhabdomyoblastic differentiation. Tumors arose in a background of a plexiform neurofibroma (16%), neurofibroma (13%), and schwannoma in two cases (3%). Immunohistochemically, H3K27me3 expression was lost in 82% of conventional high-grade MPNST analyzed, while loss of SMARCB1 expression was seen in one epithelioid MPNST. Genomically, all cases showed more than one genetic abnormality, with 53% showing mutations in EED / SUZ12 genes, and 47% of cases harboring alterations in NF1 and CDKN2A/CDKN2B genes. At the last follow-up, 30% patients died of disease, 28% were alive with disease and 42% had no evidence of disease. NF1 status did not correlate with overall survival. In conclusion, half of pediatric and young adult MPNST were NF1-related and showed loss of function alterations in PRC2 complex, NF1, and CDKN2A, similar to the adult counterpart. Thus, H3K27me3 loss of expression may be used in the diagnosis of high grade MPNSTs in children. Moreover, a small subset of pediatric MPNST have an epithelioid morphology with different pathogenesis.

Prognostic Significance of Immunohistochemical Markers and Genetic Alterations in Malignant Peripheral Nerve Sheath Tumors: A Systematic Review

Background

Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive soft tissue sarcomas with dismal prognosis. Pathological and genetic markers may predict more aggressive behavior in MPNSTs but have uncommonly been investigated, and few are used in daily practice. This study reviews the prognostic value of immunohistochemical markers and genetic alterations in MPNST.

Methods

A systematic search was performed in PubMed and Embase databases according to the PRISMA guidelines. Search terms related to ‘MPNST’ and ‘prognostic’ were used. Studies investigating the association of immunohistochemical markers or genetic alterations with prognosis were included. Qualitative synthesis was performed on all studies. A distinction was made between univariable and multivariable associations.

Results

Forty-six studies were included after full-text screening. Sixty-seven different immunohistochemical markers were investigated. Absence of S100 and H3K27me3 and high Ki67 and p53 staining was most commonly independently associated with worse survival and disease-free survival. Several genetic alterations were investigated as well with varying association to survival. TP53, CDK4, RASSF1A alterations were independently associated with worse survival, as well as changes in chromosomal length in Xp, 10q, and 16p.

Conclusions

MPNSTs harbor complex and heterogeneous biology. Immunohistochemical markers and genetic alterations have variable prognostic value. Absence of S100 and H3K27me3 and increased Ki67 can be of prognostic value. Alterations in TP53 or increase in p53 staining may distinguish MPNSTs with worse outcomes. Genetic alterations and staining of other cell cycle regulatory and Ras pathway proteins may also help stratifying patients with worse outcomes. A combination of markers can increase the prognostic value.

Prognosis and risk factors for malignant peripheral nerve sheath tumor: a systematic review and meta-analysis

Background

No available meta-analysis was printed to systematically introduce the MPNST clinic outcome and risk factors based on largely pooled data. This systematic review and meta-analysis aimed to investigate 5-year OS rate, 5-year EFS rate, and LR rate for MPNST, and to assess potential risk factors for prognosis.

Methods

Electronic articles published between January 1, 1966 and February 29, 2020 were searched and critically evaluated. The authors independently reviewed the abstracts and extracted data for 5-year OS rate, 5-year EFS rate, LR rate, and potential risk factors for prognosis.

Results

Twenty-eight literatures were finally included for meta-analysis. The pooled 5-year OS rate, 5-year EFS rate, and LR rate were 49%, 37%, and 38%, respectively. The significant prognostic factors for survival were NF1 status, tumor size, depth, location, malignant grade, margin status, chemotherapy, and radiotherapy. Age and sex were not associated with survival.

Conclusion

Survival and local recurrence of MPNST are poor. Worse prognosis is mainly associated with NF 1, large size, deep to fascia, high grade, metastases, and location (trunk and head and neck). Complete resection with adequate surgical margins is the mainstay protective factor of MPNST patients, following necessary adjuvant therapies.

Calcified Leiomyoma of the Distal Forearm in a Child: A Case Report and Review of Literature

Background

Deep somatic leiomyomas arising in skeletal muscle are extremely rare in children, especially in the extremities. Around half of them show calcifications. We present a rare case of a calcified leiomyoma of the distal forearm in a child. Case Summary. A seven-year-old boy presented with right distal forearm and wrist pain with restricted supination for 4 years. X-ray showed ring and arc calcifications in the distal forearm at the interosseous area. MRI also confirmed a well-defined soft tissue lesion with areas of calcifications. A diagnosis of a cartilage-forming lesion or a peripheral nerve sheath tumour was suggested. The lesion was completely excised. Histology showed a lesion composed of intersecting fascicles of spindle cells with stromal calcification having immunohistochemical features of a leiomyoma.

Conclusion

Although soft tissue calcifications can be seen in a plethora of conditions seen in daily orthopaedic practise, a high index of suspicion should be maintained for rare conditions like deep somatic leiomyoma.

Gastric tumors in children: single-center study with emphasis on treatment of repeated recurrence

PURPOSE

Analysis of surgical management and survival of pediatric patients with gastric tumors treated at our institution.

METHODS

A retrospective study of patients with primary gastric tumors treated between 1993 and 2018 was conducted.

RESULTS

Eight patients, five girls and three boys, were diagnosed with gastric tumors at an average age of 10.4 years (1 day-15.4 years). Surgical management included Billroth type I procedure in five and tumor excision in three patients. Histology revealed gastrointestinal stromal tumor (GIST) in four patients and one of each of schwannoma, myofibroblastic tumor, hamartoma and teratoma. Microscopically clear margins were reported in six patients. Repeated local recurrence occurred in three patients (2 × GIST, 1 × myofibroblastic tumors) who consequently underwent three, four and six reoperations. One of these patients had liver metastases, which were managed with ligation of the hepatic arteries. This patient was also diagnosed with a lung hamartoma, which was treated with a lobectomy. Survival rate was 100% with a median follow-up of 8.6 years (7 months-25.5 years).

CONCLUSIONS

Gastric tumors are rare in children and represent a management challenge. Repeated recurrence of GISTs and myofibroblastic tumors remains frequent even after complete resection and may necessitate multiple surgeries, therefore patients require a lifelong follow-up.

Neurofibromatosis-associated malignant peripheral nerve sheath tumors in children have a worse prognosis: A nationwide cohort study

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNST) are rare and aggressive non-rhabdomyoblastic soft-tissue sarcomas (NRSTS) in children. This study set out to investigate clinical presentation, treatment modalities, and factors associated with survival in pediatric MPNST using Dutch nationwide databases.

METHODS

Data were obtained from the Netherlands Cancer Registry (NCR) and the Dutch Pathology Database (PALGA) from 1989 to 2017. All primary MPNSTs were collected. Demographic differences were analyzed between adult and pediatric (age ≤18 years) MPNST. In children, demographic and treatment differences between neurofibromatosis type 1 (NF1) and non-NF1 were analyzed. A Cox proportional hazard model was constructed for localized pediatric MPNSTs.

RESULTS

A total of 70/784 MPNST patients were children (37.1% NF1). Children did not present differently from adults. In NF1 children, tumor size was more commonly large (> 5 cm, 92.3% vs 59.1%). Localized disease was primarily resected in 90.6%, and radiotherapy was administered in 37.5%. Non-NF1 children tended to receive chemotherapy more commonly (39.5% vs 26.9%). Overall, estimated five-year survival rates of localized NF1-MPNST was 52.4% (SE: 10.1%) compared with 75.8% (SE: 7.1%) in non-NF1 patients. The multivariate model showed worse survival in NF1 patients (HR: 2.98; 95% CI, 1.17-7.60, P = 0.02) and increased survival in patients diagnosed after 2005 (HR: 0.20; 95% CI, 0.06-0.69, P = 0.01). No treatment factors were independently associated with survival.

CONCLUSION

Pediatric MPNSTs have presentations similar to adult MPNSTs. In children, NF1 patients present with larger tumors, but are treated similarly to non-NF1 MPNSTs. In localized pediatric MPNST, NF1 is associated with worse survival. Promisingly, survival has increased for pediatric MPNSTs after 2005.

Primary pulmonary epithelioid malignant peripheral nerve sheath tumor in a child: a case report

Primary pulmonary malignant peripheral nerve sheath tumors (MPNSTs) are uncommon sarcomas originating from intrapulmonary nerve sheath and have been rarely observed in children. Here, we report a case of a 16-year-old child who presented with a mass located in the upper lobe of right lung. The patient underwent a sleeve lobectomy and the pathological diagnosis of the tumor was primary pulmonary epithelioid MPNST. Despite the radical resection, multiple suspected metastasis occurred in heart, lung and muscles less than 2 years after the operation and the patient died 6 months after the metastasis.

Treatment of malignant peripheral nerve sheath tumors in pediatric NF1 disease

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNSTs) are rare yet highly aggressive soft tissue sarcomas. Children with neurofibromatosis type 1 (NF1) have a 10% lifetime risk for development of MPNST. Prognosis remains poor and survival seems worse for NF1 patients.

METHODS

This narrative review highlights current practices and pitfalls in the management of MPNST in pediatric NF1 patients.

RESULTS

Preoperative diagnostics can be challenging, but PET scans have shown to be useful tools. More recently, functional MRI holds promise as well. Surgery remains the mainstay treatment for these patients, but careful planning is needed to minimize postoperative morbidity. Functional reconstructions can play a role in improving functional status. Radiotherapy can be administered to enhance local control in selected cases, but care should be taken to minimize radiation effects as well as reduce the risk of secondary malignancies. The exact role of chemotherapy has yet to be determined. Reports on the efficacy of chemotherapy vary as some report lower effects in NF1 populations. Promisingly, survival seems to ameliorate in the last few decades and response rates of chemotherapy may increase in NF1 populations when administering it as part of standard of care. However, in metastasized disease, response rates remain poor. New systemic therapies are therefore desperately warranted and multiple trials are currently investigating the role of drugs. Targeted drugs are nevertheless not yet included in first line treatment.

CONCLUSION

Both research and clinical efforts benefit from multidisciplinary approaches with international collaborations in this rare malignancy.

Pediatric peripheral nerve tumors: clinical and surgical aspects

PURPOSE

Pediatric peripheral nerve tumors (PNTs) are rare. Most are related to neurofibromatosis type 1 (NF1) with the potential for malignancy. An ongoing debate occurs about the best approach to such patients. This study describes a cohort of pediatric patients with PNTs and discusses clinical characteristics and surgical treatment.

METHODS

We retrospectively reviewed the charts of seven pediatric patients with eight PNTs surgically treated from 2007 to 2018. Information concerning patient demographics, clinical presentation, PNTs characteristics, treatment choice, and outcome were recorded.

RESULTS

All children presented with intense pain and a palpable mass. Three of the eight tumors were associated with a neurological deficit. Among the four patients with NF1, two had a neurofibroma and two a malignant peripheral nerve sheath tumor (MPNST). Histologically, three of the lesions were a benign peripheral nerve sheath tumor (BPNST), three a MPNST, and one each a desmoid tumor and Ewing's sarcoma. Two of the eight tumors underwent partial tumor excision and six gross total excisions.

CONCLUSIONS

Intense pain at rest, day, and/or night, preventing normal activities; a palpable, hard, immobile mass; an intense Tinel's sign related to the lump; clinical evidence of NF1; and high-speed growth of a tumor in the trajectory of the nerve or plexus should alert the clinician to the potential for malignancy. Preoperative biopsy is not indicated when clinical and imaging findings suggest a benign tumor. The surgical management of PNTs must be to achieve total resection, including wide margins with malignant tumors, though this is not always possible.

Treatment and survival differences across tumor sites in malignant peripheral nerve sheath tumors: a SEER database analysis and review of the literature

Background

Currently, literature is scarce on differences across all possible tumor sites in malignant peripheral nerve sheath tumors (MPNSTs). To determine differences in treatment and survival across tumor sites and assess possible predictors for survival, we used the Surveillance, Epidemiology, and End Results (SEER) database.

Methods

MPNST cases were obtained from the SEER database. Tumor sites were recoded into: intracranial, spinal, head and neck (H&N), limbs, core (thorax/abdomen/pelvis), and unknown site of origin. Patient and tumor characteristics, treatment modalities, and survival were extracted. Overall survival (OS) was assessed using univariable and multivariable Cox regression hazard models. Kaplan-Meier survival curves were constructed per tumor site for OS and disease-specific survival (DSS).

Results

A total of 3267 MPNST patients were registered from 1973 to 2013; 167 intracranial (5.1%), 119 spinal (3.6%), 449 H&N (13.7%), 1022 limb (31.3%), 1307 core (40.0%), and 203 unknown (6.2%). The largest tumors were found in core sites (80.0 mm, interquartile range [IQR]: 60.0-115.0 mm) and the smallest were intracranial (37.4 mm, IQR: 17.3-43.5 mm). Intracranial tumors were least frequently resected (58.1%), whereas spinal tumors were most often resected (83.0%). Radiation was administered in 35.5% to 41.8%. Independent factors associated with decreased survival were: older age, male sex, black race, no surgery, partial resection, large tumor size, high tumor grade, H&N site, and core site (all P < .05). Intracranial and pediatric tumors show superior survival (both P < .05). Intracranial tumors show superior OS and DSS curves, whereas core tumors have the worst (P < .001).

Conclusion

Superior survival is seen in intracranial and pediatric MPNSTs. Core and H&N tumors have a worse prognosis.

Salvage rates and prognostic factors after relapse in children and adolescents with malignant peripheral nerve sheath tumors

BACKGROUND

Malignant peripheral nerve sheath tumor (MPNST) is one of the most common nonrhabdomyosarcoma soft tissue sarcomas encountered in pediatric age, and it is generally characterized by poor outcome, particularly for relapsing patients.

MATERIALS AND METHODS

This study considered 73 patients <21 years of age with relapsing MPNST observed among 120 patients enrolled in Italian pediatric protocols from 1979 to 2004. With the aim of possibly establishing a risk-adapted stratification, patients' outcome was examined using univariate and multivariate analysis based on clinical features at onset, first-line treatments, clinical findings at the time of first relapse, and second-line treatments.

RESULTS

The time to relapse ranged from 1 to 204 months after first diagnosis (median 7 months). The first relapse event was mainly local. At the time of our analysis, nine patients were alive in remission. The median overall survival after first relapse was 11 months, and the survival rates were 39.2% at 1 year and 15.8% at 5 years. The factors revealing the greatest impact on prognosis were as follows: initial tumor invasiveness, time of relapse, and achievement of a secondary complete remission (which was related to the feasibility of radical surgery).

CONCLUSIONS

Our study confirmed the unsatisfactory prognosis for pediatric patients with relapsing MPNST and pointed to a risk-adapted stratification model for the purposes of deciding second-line treatments. For the time being, an aggressive surgical approach seems to be the only effective salvage treatment and should be recommended. New therapeutic approaches are under evaluation with a view to improving current outcomes.

SARC006: Phase II Trial of Chemotherapy in Sporadic and Neurofibromatosis Type 1 Associated Chemotherapy-Naive Malignant Peripheral Nerve Sheath Tumors

Background

Worse chemotherapy response for neurofibromatosis type 1- (NF1-) associated compared to sporadic malignant peripheral nerve sheath tumors (MPNST) has been reported.

Methods

We evaluated the objective response (OR) rate of patients with AJCC Stage III/IV chemotherapy-naive NF1 MPNST versus sporadic MPNST after 4 cycles of neoadjuvant chemotherapy, 2 cycles of ifosfamide/doxorubicin, and 2 cycles of ifosfamide/etoposide. A Simon optimal two-stage design was used (target response rate 40%).

Results

34 NF1 (median age 33 years) and 14 sporadic (median age 40 years) MPNST patients enrolled. Five of 28 (17.9%) evaluable NF1 MPNST patients had a partial response (PR), as did 4 of 9 (44.4%) patients with sporadic MPNST. Stable disease (SD) was achieved in 22 NF1 and 4 sporadic MPNST patients. In both strata, results in the initial stages met criteria for expansion of enrollment. Only 1 additional PR was observed in the expanded NF1 stratum. Enrollment was slower than expected and the trial closed before full accrual.

Conclusions

This trial was not powered to detect differences in response rates between NF1 and sporadic MPNST. While the OR rate was lower in NF1 compared to sporadic MPNST, qualitative responses were similar, and disease stabilization was achieved in most patients.

Role of Histone H3K27 Trimethylation Loss as a Marker for Malignant Peripheral Nerve Sheath Tumor in Fine-Needle Aspiration and Small Biopsy Specimens

OBJECTIVES

Accurate diagnosis of malignant peripheral nerve sheath tumor (MPNST) is often challenging on fine-needle aspiration (FNA) or core needle biopsy. Recurrent mutations in EED and SUZ12, which encode subunits of polycomb repressive complex 2 (PRC2), have been identified in 70% to 92% of MPNSTs; PRC2 inactivation leads to loss of trimethylation of lysine 27 of histone H3 (H3K27me3). We evaluated the utility of H3K27me3 immunohistochemistry for distinguishing MPNST from its cytomorphologic mimics.

METHODS

H3K27me3 immunohistochemistry was performed on 180 cases of spindle cell neoplasms sampled by FNA (n = 66) and needle biopsy (n = 114), and loss of nuclear staining was scored. Tumor types included MPNST, dedifferentiated liposarcoma, schwannoma, solitary fibrous tumor, leiomyosarcoma, melanoma, synovial sarcoma, sarcomatoid carcinoma, gastrointestinal stromal tumor, desmoid fibromatosis, low-grade fibromyxoid sarcoma, and unclassified spindle cell sarcoma/undifferentiated pleomorphic sarcoma.

RESULTS

Complete loss of H3K27me3 was observed in 54% (13/24) of MPNSTs. In contrast, only two (of 156) histologic mimics showed complete loss of H3K27me3. Partial loss of H3K27me3 was present in a subset of cases (26/180), including both MPNST and non-MPNSTs.

CONCLUSIONS

Complete loss of H3K27me3 is a highly specific (98.7%) marker of MPNST that can distinguish MPNST from cytomorphologic mimics in FNA cell block and small biopsy specimens.

Clear Cell Sarcoma of Tendons and Aponeuroses

Fifty-eight previously unreported cases of clear cell sarcoma of tendons and apo neuroses occurring in 29 males and 29 females with a median age of 31 years are presented. The distal extremities were most frequently involved (58%), followed by the limbs and limb girdles (33%), and trunk (9%). Median tumor size was 2.5 cm (range, 0.6-9 cm). Kaplan-Meier estimates revealed a 5-year survival rate of 63%. Eleven of 43 patients (26%) had local recurrences at a median interval of 33 months. Metastases occurred in 20 of 45 cases (44%) at a median interval of 26 months; 19 of 20 patients with metastases died of the disease. The most common metastatic site was the lungs (11 cases), followed by bone (9 cases), and lymph nodes (8 cases). Clear cell sarcoma had a stereotypic morphology consisting of packeted arrangements of uniform, round to fusiform cells with eosinophilic to clear glycogen-rich cytoplasm, and prominent nucleoli, as well as multinucleated tumor cells with a wreath-like arrangement of nuclei. S100 protein was detected in all 44 cases studied, vimentin in 36, and HMB45 stained 36. Twenty-six cases were studied with antibodies directed against proliferating cell nuclear antigen. Neither the intensity of proliferating cell nuclear antigen staining, percentage of positive cells, nor the combined score of these two variables corresponded with mitotic rate or survival. Increasing size (as a continu ous variable) and necrosis were found to be independent adverse prognostic factors by multivariate analysis. Int J Surg Pathol 1 (2):89-100, 1993

Long-term progress of six cases of malignant peripheral nerve sheath tumors of the mediastinum that underwent surgical treatment: Case report series

INTRODUCTION

Malignant Peripheral Nerve Sheath Tumor is a rare type of soft tissue malignant tumor that occurs in only 5% of cases. It tends to occur in the arms and legs and trunk of the body, with mediastinal occurrence in only a few cases. Among mediastinal tumors, only 18.8% occur primarily in the nerves, and of these, only 10.3% are malignant, with very few reports indicating the long-term progress of patients with MPNST of the mediastinum.

CASE PRESENTATION

We studied six cases of mediastinal primary malignant peripheral nerve sheath tumors in which surgery was carried out at this Center between 1977 and 2000. Four of the cases were men and two were women. The period of observation was between 14 and 277 months and the median follow-up time was 119.5 months. The tumors were contained in a membrane and completely excisable in three cases, with the patient demonstrating long-term survival with no recurrence in each case. The remaining three cases were not completely excisable due to invasion into the aorta. In two cases, the patients were treated post-surgically with chemotherapy; however, in all three cases the patient died as a result of the original condition.

DISCUSSION AND CONCLUSIONS

Nerve sheath tumors localized within the membrane offer good long-term prognosis even if malignant. Furthermore, long-term survival is possible even if the tumor has invaded neighboring organs, provided it can be completely excised. In cases where complete excision is difficult, a multidisciplinary approach including radiotherapy and anti-cancer drug treatment may contribute to improved prognosis but this is a subject that requires further study.

Malignant Peripheral Nerve Sheath Tumor in Frontal Sinus, Orbital Cavity and Ethmoid Cavity

Malignant peripheral nerve sheath tumors are extremely rare soft tissue sarcomas. Among various locations, the trunk and extremities are the most commonly involved sites, with only 15% of such lesions occuring in head and neck region. Here, we report a case of a 74-year-old male who presented with forehead swelling and right eye deviation. Computed tomography images revealed a tumor involving the frontal sinus, ethmoid sinus, and the orbital cavity. The patient underwent a surgical excision of the lesion, which histopathological examination revealed to be a malignant peripheral nerve sheath tumor.

Malignant peripheral nerve sheath tumor of the distal phalanx of the fifth toe: a case report

Malignant peripheral nerve sheath tumor (MPNST) involving bone is rare. We report a case of MPNST of the fifth toe. The lesion was located in the distal phalanx of the right fifth toe and extended into surrounding subcutaneous tissues. Findings on magnetic resonance imaging and histological features of the case are described and the literature is briefly reviewed.

Pediatric and adult malignant peripheral nerve sheath tumors: an analysis of data from the surveillance, epidemiology, and end results program

Malignant peripheral nerve sheath tumors (MPNSTs) are rare soft tissue sarcomas that arise predominantly from Schwann cells. Despite the fact that MPNSTs have high local recurrence rates and are generally associated with poor prognosis, little is known about prognostic factors or effective clinical management for this tumor type. The purpose of this study was to describe the distributions of patient and tumor characteristics and to identify predictors of cause-specific survival among MPNST cases reported to SEER between 1973 and 2008. Patient and tumor characteristics were compared between pediatric and adult MPNST cases. Cox regression and tree-based survival analysis were used to examine factors associated with MPNST-related mortality separately among adults and children. A total of 1,315 MPNST cases were isolated from the 1973-2008 SEER dataset. Among pediatric cases, sex, race, and radiation therapy predicted MPNST survival, whereas among adults, tumor site, tumor grade, number of primary tumors, and tumor size were significant predictors. As tumor size at diagnosis/resection may be the only somewhat "modifiable" prognostic factor, future studies should aim to identify biological and social attributes associated with tumor size at diagnosis, separately among individuals with and without NF-1, in order to help identify earlier opportunities for clinical intervention.

Survivin expression and prognostic significance in pediatric malignant peripheral nerve sheath tumors (MPNST)

Malignant peripheral nerve sheath tumors (MPNST) are very aggressive malignancies comprising approximately 5–10% of all soft tissue sarcomas. In this study, we focused on pediatric MPNST arising in the first 2 decades of life, as they represent one the most frequent non-rhabdomyosarcomatous soft tissue sarcomas in children. In MPNST, several genetic alterations affect the chromosomal region 17q encompassing the BIRC5/SURVIVIN gene. As cancer-specific expression of survivin has been found to be an effective marker for cancer detection and outcome prediction, we analyzed survivin expression in 35 tumor samples derived from young patients affected by sporadic and neurofibromatosis type 1-associated MPNST. Survivin mRNA and protein expression were assessed by Real-Time PCR and immunohistochemical staining, respectively, while gene amplification was analyzed by FISH. Data were correlated with the clinicopathological characteristics of patients. Survivin mRNA was overexpressed in pediatric MPNST and associated to a copy number gain of BIRC5; furthermore, increased levels of transcripts correlated with a higher FNCLCC tumor grade (grade 1 and 2 vs. 3, p = 0.0067), and with a lower survival probability (Log-rank test, p = 0.0038). Overall, these data support the concept that survivin can be regarded as a useful prognostic marker for pediatric MPNST and a promising target for therapeutic interventions.

Malignant peripheral nerve sheath tumor of the penis: a case report and review of the literature

Malignant peripheral nerve sheath tumors (MPNSTs) are rare soft tissue sarcomas that arise from peripheral nerve fibers and are derived from Schwann cells, perineural cells, or fibroblasts. MPNST is an aggressive neoplasm in which local recurrence is common and complete excision of the mass should be the goal of surgery. We report a case of MPNST involving the penis in a 14-month-old boy. This is only the second reported case of penile MPNST without evidence of neurofibromatosis 1 and the first of which to occur in a patient this young.

Survival meta-analyses for >1800 malignant peripheral nerve sheath tumor patients with and without neurofibromatosis type 1

There are conflicting reports as to whether malignant peripheral nerve sheath tumor (MPNST) patients with neurofibromatosis type 1 (NF1) have worse prognosis than non-NF1 MPNST patients. Large clinical studies to address this problem are lacking due to the rareness of MPNST. We have performed meta-analyses testing the effect of NF1 status on MPNST survival based on publications from the last 50 years, including only nonoverlapping patients reported from each institution. In addition, we analyzed survival characteristics for 179 MPNST patients from 3 European sarcoma centers. The meta-analyses including data from a total of 48 studies and >1800 patients revealed a significantly higher odds ratio for overall survival (OR(OS)) and disease-specific survival (OR(DSS)) in the non-NF1 group (OR(OS) = 1.75, 95% confidence interval [CI] = 1.28-2.39, and OR(DSS) = 1.68, 95% CI = 1.18-2.40). However, in studies published in the last decade, survival in the 2 patient groups has been converging, as especially the NF1 group has shown improved prognosis. For our own MPNST patients, NF1 status had no effect on overall or disease-specific survival. The compiled literature from 1963 to the present indicates a significantly worse outcome of MPNST in patients with NF1 syndrome compared with non-NF1 patients. However, survival for the NF1 patients has improved in the last decade, and the survival difference is diminishing. These observations support the hypothesis that MPNSTs arising in NF1 and non-NF1 patients are not different per se. Consequently, we suggest that the choice of treatment for MPNST should be independent of NF1 status.

Neurogenic tumors of soft tissue

Neurogenic tumors are an uncommon yet important category of soft tissue tumors in children and adolescents because of their frequent association with various genetic syndromes. The heterogeneous cellular composition of the peripheral nerve and the wide metaplastic capacity of the neural crest and its derivatives generate a variety of neoplasms with neurogenic differentiation. This article reviews the clinicopathologic features and differential diagnosis of neurogenic tumors in the first two decades of life, and highlights use of selected ancillary methods for diagnosis.

Primary malignant peripheral nerve sheath tumor of the cauda equina with metastasis to the brain in a child: case report and literature review

BACKGROUND CONTEXT

Primary intradural malignant peripheral nerve sheath tumors (MPNSTs) are extremely rare; only 23 cases have been reported in the English-language literature till now. No gold standard for treating primary intradural MPNSTs has yet been established.

PURPOSE

To report a rare case of primary intradural MPNSTs in a child and review the literature pertaining to this rare disease.

STUDY DESIGN/SETTING

Case report and literature review.

METHODS

We report our experience with one new case. An 8-year-old boy diagnosed with primary intradural MPNSTs underwent three surgical excisions and two rounds of radiotherapy; however, metastasis to the brain was found, and the boy died 16 months after the first surgery. We also review the literature pertaining to both MPNSTs in general and primary intradural MPNSTs.

RESULTS

Surgery is currently the mainstay of MPNST treatment. Radiotherapy and chemotherapy are of limited value in these tumors. Based on the review of the 24 cases described in the literature, including the present case, primary intradural MPNST is a very aggressive tumor with a very high recurrence rate even after gross total resection and with significant potential for leptomeningeal and systemic metastasis. The overall prognosis is very poor and seems to be worse than that of MPNSTs in general.

CONCLUSIONS

Primary intradural MPNST is a very rare entity with a poor prognosis. Surgical tumor removal combined with postoperative high-dose radiation may be recommended. Chemotherapy is usually reserved for patients with disseminated metastases or tumors that are unresectable at the time of diagnosis.

Pathology of peripheral nerve sheath tumors: diagnostic overview and update on selected diagnostic problems

Peripheral nerve sheath tumors are common neoplasms, with classic identifiable features, but on occasion, they are diagnostically challenging. Although well-defined subtypes of peripheral nerve sheath tumors were described early in the history of surgical pathology, controversies regarding the classification and grading of these tumors persist. Advances in molecular biology have provided new insights into the nature of the various peripheral nerve sheath tumors, and have begun to suggest novel targeted therapeutic approaches. In this review, we discuss current concepts and problematic areas in the pathology of peripheral nerve sheath tumors. Diagnostic criteria and differential diagnosis for the major categories of nerve sheath tumors are proposed, including neurofibroma, schwannoma, and perineurioma. Diagnostically challenging variants, including plexiform, cellular and melanotic schwannomas are highlighted. A subset of these affects the childhood population, and has historically been interpreted as malignant, although current evidence and outcome data suggest they represent benign entities. The growing current literature and the author's experience with difficult to classify borderline or "hybrid tumors" are discussed and illustrated. Some of these classification gray zones occur with frequency in the gastrointestinal tract, an anatomical compartment that must always be entertained when examining these neoplasms. Other growing recent areas of interest include the heterogeneous group of pseudoneoplastic lesions involving peripheral nerve composed of mature adipose tissue and/or skeletal muscle, such as the enigmatic neuromuscular choristoma. Malignant peripheral nerve sheath tumors (MPNST) represent a diagnostically controversial group; difficulties in grading and guidelines to separate "atypical neurofibroma" from MPNST are provided. There is an increasing literature of MPNST mimics which neuropathologists must be aware of, including synovial sarcoma and ossifying fibromyxoid tumor. Finally, we discuss entities that are lacking from the section on cranial and paraspinal nerves in the current WHO classification, and that may warrant inclusion in future classifications. In summary, although the diagnosis and classification of most conventional peripheral nerve sheath tumors are relatively straightforward for the experienced observer, yet borderline and difficult-to-classify neoplasms continue to be problematic. In the current review, we attempt to provide some useful guidelines for the surgical neuropathologist to help navigate these persistent, challenging problems.

Malignant peripheral nerve sheath tumor with primitive neuroepithelial differentiation in an adult: a case report

Primitive neuroepithelial differentiation in malignant peripheral nerve sheath tumors (MPNSTs) has been reported in children but is extremely rare in adults. The authors report the case of a 70-year-old woman who presented with swelling of the right leg of 1-month duration. Fine-needle aspiration cytology was suggestive of a benign peripheral nerve sheath tumor. Histopathological examination of the excised mass revealed a MPNST with spindle-cell areas and a few round-cell areas with rosettes. The spindle cells showed positive immunoreactivity for S-100 protein and vimentin and negativity for desmin, confirming their nerve sheath origin. The round cells were immunoreactive for synaptophysin and chromogranin, indicating primitive neuroepithelial differentiation. These cells did not stain for CD99, which is consistently expressed by the cells of primitive neuroectodermal tumors (PNETs) of bone and soft tissue but not by central nervous system (CNS) PNETs or medulloblastomas. In this case, the PNET-like focus resembled a CNS-PNET.

Malignant peripheral nerve sheath tumors in Africa: a clinicopathological study

Introduction. Malignant peripheral nerve sheath tumors (MPNSTs) are rare, aggressive soft tissue sarcomas associated with poor prognosis, that most commonly affect patients aged 20 to 50 years, but have also been reported in children. There is little reported in literature on these tumors in Africa. Materials and Methods. A search of the hospital pathology database between 1992 and 2008 revealed 333 nerve sheath tumors, of which 31 were MPNSTs. Four representative case reports are presented. Discussion. MNPSTs have rarely been reported from sub-Saharan Africa; in this study, they constituted 9.3% of all nerve sheath tumors. The trunk (42%) and limbs (45%) were the most frequently affected anatomical sites. Late presentation of malignant lesions in this environment is exemplified by the four case presentations patients. Conclusions. This report confirms observations from studies on MPNSTs from other environments. Anatomically centrally located MPNSTs may have a higher incidence in sub-Saharan Africa than in the West. Because NF1-associated MPNSTs are difficult to diagnose clinically, and because surgery is the only mode of therapy that offers a complete cure, a lifetime follow-up is important, as this would enable diagnosis of early lesions amenable to surgical extirpation.

High grade malignant peripheral nerve sheath tumors: outcome of 62 patients with localized disease and review of the literature

Malignant peripheral nerve sheath tumours (MPNST) are rare sarcomas with one of the poorest prognoses of all the soft tissue sarcomas. Information about adjuvant treatment is scarce and not homogeneous for this diagnosis. We analyzed retrospectively the outcome of patients with localized high grade MPNST admitted to our institute from 1969 to 2008. A review of the literature is also reported. Of 62 evaluable patients, 23 were females and 39 males, median age 39 years (17-71), 22/62 had neurofibromatosis type I. Median follow-up was 54 months (range 12-194). A total of 22/62 are alive; 26 patients had surgery alone, 18 received radiation therapy, 12 received radiation therapy and chemotherapy, and 6 received only adjuvant chemotherapy. The 5-year disease-free survival was 30% and 5-year overall survival was 38%. A positive trend for adjuvant radiation, but not for chemotherapy was observed according to univariate analysis only for disease-free survival and overall survival. Multivariate analysis indicated that primary site, size and surgical margins remained significant for disease-free survival and only site and size were significant for overall survival. New drugs employed successfully in advanced mpNSt should be employed also in the adjuvant setting.

Malignant peripheral nerve sheath tumor mimicking carotid body tumor--case report and review

Malignant peripheral nerve sheath tumor is a rare neurogenic tumor that usually presents in geriatic patients. Typically, it is found in the trunk and extremities and rarely presents in the head and neck region. It may mimic a carotid body tumor when it presents in the neck. We report the first case of malignant peripheral nerve sheath tumor of the vagus nerve in an adolescent boy. He presented with an asymptomatic lateral neck lump that was thought to be a benign schwannoma on preoperative imaging. We describe the diagnostic dilemma and management difficulties in this patient and review the literature.

Primary pediatric intraspinal sarcomas. Report of 3 cases

Sarcomas that arise from within the spinal canal are rare, particularly within the pediatric population. In general, these primary intraspinal sarcomas are highly aggressive, posing unique treatment challenges with respect to surgery and choice of adjuvant therapy. The goal must be to obtain the most complete resection possible to minimize the risk of recurrence and metastasis, while preventing potential neurological deficits that may result from aggressive surgery. Among these primary intraspinal sarcomas are malignant peripheral nerve sheath tumors and members of the Ewing sarcoma family of tumors. The authors present 3 cases of unique spinal sarcomas in children-2 malignant peripheral nerve sheath tumors in patients without neurofibromatosis and an intradural extraosseous Ewing sarcoma arising from the sensory component of a lumbar spinal nerve-and discuss their management and outcome with a review of the current literature.

Plexiform malignant peripheral nerve sheath tumour of infancy and childhood of the index finger: Surgical treatment

We describe a rare case of plexiform malignant peripheral nerve sheath tumour (MPNST) of infancy and childhood in a 3.5-year-old girl. The tumour was located in the proximal phalanx of the left index finger. After initial excisions and a ray amputation, exarticulation of the third and fourth rays was required.

Malignant orbital schwannoma with massive intracranial recurrence

BACKGROUND

A 62 year old male presented with progressive diplopia, left orbital pain and impairment of visual acuity.

METHOD AND FINDINGS

Neuroradiological investigation disclosed an orbital tumour. The lesion was totally excised. Histopathology examination revealed a malignant peripheral nerve sheath tumour (MPNST). The tumour recurred with intracranial extension. The patient died 13 months after the initial diagnosis.

CONCLUSIONS

To our knowledge, this is the first reported example of a massive intracranial recurrence of an orbital MPNST. The epidemiological features, clinical course and treatment of these lesions are discussed.

Undifferentiated tumor: true identity by immunohistochemistry

CONTEXT

"Undifferentiated tumor" refers to a heterogeneous group of neoplasms with little or no evidence of differentiation on routine light microscopic morphology.

OBJECTIVE

To identify the true identity of undifferentiated tumors by immunohistochemical analysis.

DATA SOURCES

Review of the pertinent literature and the authors' experience.

CONCLUSIONS

For treatment and prognostic evaluation, it is crucial to delineate whether an undifferentiated neoplasm is epithelial, mesenchymal, melanocytic, or hematopoietic in nature. Application of a screening panel to demonstrate the expression of markers of major lineages is fundamental for determination of the broad category of neoplasia. Because poorly differentiated carcinomas and in particular sarcomatoid carcinomas are known to be heterogeneous in their antigen expression, several epithelial markers in combination may be required to establish the carcinomatous nature of tumor. A diagnostic misinterpretation as a consequence of occasional aberrant or unexpected antigen expression is best avoided by using a broad panel that includes both antibodies that are anticipated to be positive and those that are expected to be negative. In this treatise, the immunohistochemical dissection of undifferentiated tumors on the basis of their morphologic features is outlined, supplemented with algorithmic immunohistochemical analysis for each morphologic category of small round cell tumors, carcinomatous tumors, sarcomatous (or sarcoma-like) tumors, and tumors with histologically overlapping features, including hematolymphoid malignancies, melanoma, and sarcomas with epithelioid appearance. The utility of several organ- or tissue-specific markers in the context of undifferentiated tumors is reviewed.

Management of childhood malignant peripheral nerve sheath tumor

Malignant peripheral nerve sheath tumor (MPNST) is rare, but is one of the most frequent non-rhabdomyosarcoma soft-tissue sarcomas in the pediatric population. These tumors occur most frequently at axial sites and are characterized by local aggressiveness and a propensity to metastasize. They are often associated with neurofibromatosis type 1 (NF-1): the lifetime risk of patients with NF-1 developing MPNST has been estimated at 8-13%, compared with 0.001% in the general population. Because of the rarity of this tumor, little information is available on its clinical management, particularly in the pediatric age group. In a recent report on the clinical findings and treatment outcomes from a large number of children and adolescents with MPNST in an Italian and German series, less satisfactory overall outcomes than those for other pediatric sarcomas were described. Therefore, the approach to the treatment of patients with MPNST should be aggressive and risk adapted, and is necessarily complex. Patients should be referred to selected institutions with adequate experience in treating soft-tissue sarcomas, and with the multidisciplinary skills for enrolling patients in clinical trials. Surgical resection represents the mainstay of treatment, while the role of adjuvant treatment is not yet clear. Post-operative radiotherapy seems to have a role in improving local control, although the potential morbidity of irradiation should be taken into account, particularly when treating children. Although lack of local control is the major cause of treatment failure, MPNST may give rise to distant metastases. These tumors are usually considered as having uncertain chemosensitivity, but recent evidence suggests that there may be a role for chemotherapy in patients with a high-grade histology. For the near future, our hopes lie in the development of novel tailored therapies directed specifically against the molecular targets of the neoplastic cells: soft-tissue sarcomas seem particularly promising candidates for targeted therapy.

Sarcomas in children with neurofibromatosis type 1-poor prognosis despite aggressive combined therapy in four patients treated in a single oncological institution

OBJECTS

Patients with neurofibromatosis type 1 (NF1) are predisposed to developing soft tissue sarcomas (STS).

MATERIALS AND METHODS

We report on four cases of STS diagnosed in locally advanced, unresectable stages in children with NF1 (three girls, one boy; age = 8 months-14 years). All patients received protocols for STS: Cooperative Weichteilsarkomstudie 91, 96 and 2002. One patient with limb rhabdomyosarcoma entered complete remission but developed late metastatic relapse and died of progression despite complete excision and autologous bone marrow transplantation. The other patient with bladder rhabdomyosarcoma died of neutropenia-related sepsis without remission. Patients with malignant peripheral nerve sheet tumour and malignant triton tumour located in the pelvis did not respond to therapy. One of them died of disease progression, while the other is disease-free 6 years post-therapy after mutilating tumour resection.

CONCLUSION

STS in NF1 seem to display poor prognosis in spite of combined therapy; thus, children with NF1 should remain under detailed control of the oncologist.

Nestin expression as a new marker in malignant peripheral nerve sheath tumors

Malignant peripheral nerve sheath tumor (MPNST) can be difficult to diagnose because it lacks specific immunohistochemical markers. S-100, which is a useful marker of MPNST, has limited diagnostic utility. Recent studies suggest that nestin, which is an intermediate filament protein, is expressed in neuroectodermal stem cells. The diagnostic utility of immunostains for nestin and three other neural markers (S-100, CD56 and protein gene product 9.5 (PGP 9.5)) were evaluated in 35 cases of MPNST and in other spindle cell tumors. All MPNST cases were strongly positive for nestin and had cytoplasmic staining. Stains for S-100, CD56, and PGP 9.5 were positive in fewer cases (17/35, 11/35, and 29/35 cases, respectively), and had less extensive staining. Nestin was negative in 10/10 leiomyomas, and weak nestin expression was seen in 10/10 schwannomas, 3/10 neurofibromas, 2/8 synovial sarcomas, 2/10 liposarcomas, 4/7 carcinosarcomas and 3/7 malignant fibrous histiocytomas. In contrast, strong nestin positivity was seen in 10/10 rhabdomyosarcomas, 15/19 leiomyosarcomas, and 9/9 desmoplastic melanomas. Nestin is more sensitive for MPNST than other neural markers and immunostains for nestin in combination with other markers could be useful in the diagnosis of MPNST.

Soft-tissue sarcomas in children and adolescents with neurofibromatosis type 1

BACKGROUND

Patients affected by neurofibromatosis type 1 (NF1) are at higher risk of developing soft-tissue sarcomas (STS) than the general population. The clinical findings and outcome in 43 children and adolescents with NF1 treated for STS in the Italian protocols between 1988 and 2004 are reported.

METHODS

The study included 37 patients with neurogenic sarcomas (36 malignant peripheral nerve sheath tumors [MPNST], 1 triton tumor) and 6 cases of rhabdomyosarcoma (RMS). The prevalence of NF1 observed during the study period was 43% in the MPNST population and 1% in the RMS group.

RESULTS

Most patients with neurogenic sarcomas had large, invasive tumors. Five-year event-free and overall survival rates were 19% and 28%, respectively. Two of 16 patients with evaluable disease responded to chemotherapy. All 6 RMS patients were </=3 years old and had embryonal subtype, 5 of 6 arising in the genitourinary tract or pelvis (paravesical); 4 were alive in first remission at the time of the analysis, 1 was alive in second remission after a local recurrence, and 1 died of disease.

CONCLUSIONS

The occurrence of STS in pediatric patients with NF1 syndrome in Italy is discussed, confirming that NF1 patients have a high risk of developing STS, and particularly MPNST, often with an aggressive clinical presentation and poor outcome. Cases of RMS tended to have particular features (early age, embryonal histotype, genitourinary site) and their outcome seemed to resemble that of the general RMS population.

Primary malignant peripheral nerve sheath tumor of the lung in a young child without neurofibromatosis type 1

Malignant peripheral nerve sheath tumors (MPNST) are uncommon in children and almost half of the cases occur in patients with neurofibromatosis 1 (NF1). We report a child with a primary MPNST of the lung without NF1. MPNST of the lung has similar clinical and radiologic characteristics as pleuropulmonary blastoma. We suggest to include MPNST of the lung in the differential diagnosis of intrapulmonary masses in children.

Malignant Peripheral Nerve Sheath Tumors of the Head and Neck: Two Cases and a Review of the Literature

Malignant peripheral nerve sheath tumors are uncommon lesions that occasionally affect the head and neck. We describe 2 new cases of head and neck pathology. One tumor involved the parotid gland and resulted in erosion of the temporal bone, and the other affected the lower lip. A rapid diagnosis has significant implications for management because of the tumor's potential for aggressive behavior and its high rate of recurrence. To the best of our knowledge, lip involvement is rare and temporal bone involvement has not been previously described.