Pediatric malignant peripheral nerve sheath tumor: the Italian and German soft tissue sarcoma cooperative group

Favorable outcome after radical resection and subsequent local irradiation of malignant peripheral nerve sheath tumor in the cervical spine

A 25-year-old man presented with malignant transformation to malignant peripheral nerve sheath tumor (MPNST) in the cervical spine associated with neurofibromatosis type 1. He presented with a 3-week history of rapidly increasing weakness and numbness in all four extremities. Magnetic resonance (MR) imaging of the cervical spine demonstrated a dumbbell-shaped tumor, which compressed the spinal cord at the C2-3 level. The tumor was excised, mainly within the spinal canal to decompress the spinal cord. The histological diagnosis was benign neurofibroma. Three months after surgery, he rapidly developed progressive tetraparesis and MR imaging revealed marked regrowth of an extradural mass into the spinal canal. At reoperation, the regrown mass in the spinal canal was totally excised. The histological diagnosis revealed MPNST. He underwent radiation therapy, with a total dose of 32 Gy, for approximately 3 weeks after the second surgery, but MR imaging showed tumor regrowth within the spinal canal, and his condition deteriorated. The decision was made to remove the tumor radically, including the involved facet and extradural lesion. Posterior fusion using a pedicle screw was performed one month later. He manifested no additional neurological deficits. He has been free of relapse for 46 months. Radical resection remains the most effective treatment for MPNST, although complete removal with a clear tumor margin is often impossible in practice.

Usefulness of whole-body fluorine-18-fluorodeoxyglucose positron emission tomography in patients with neurofibromatosis type 1: a systematic review

Aim. To systematically review the role of positron emission tomography (PET) with fluorine-18-fluorodeoxyglucose (FDG) in patients with neurofibromatosis type 1 (NF1). Methods. A comprehensive literature search of published studies regarding FDG-PET and PET/CT in patients with NF1 was performed. No beginning date limit and language restriction were used; the search was updated until December 2011. Only those studies or subsets in studies including whole-body FDG-PET or PET/CT scans performed in patients with NF1 were included. Results. We identified 12 studies including 352 NF1 patients. Qualitative evaluation was performed in about half of the studies and semiquantitative analysis, mainly based on different values of SUV cutoff, in the others. Most of the studies evaluated the role of FDG-PET for differentiating benign from malignant peripheral nerve sheath tumors (MPNSTs). Malignant lesions were detected with a sensitivity ranging between 100% and 89%, but with lower specificity, ranging between 100% and 72%. Moreover, FDG-PET seems to be an important imaging modality for predicting the progression to MPNST and the outcome in patients with MPNST. Two studies evaluated the role of FDG-PET in pediatric patients with NF1. Conclusions. FDG-PET and PET/CT are useful methods to identify malignant change in neurogenic tumors in NF1 and to discriminate malignant from benign neurogenic lesions.

Molecular therapies for tuberous sclerosis and neurofibromatosis

Neurofibromatosis type 1 (NF1) and tuberous sclerosis complex (TSC) are autosomal-dominant genetic disorders that result from dysregulation of the PI3K/AKT/mammalian target of rapamycin (mTOR) pathway. NF1 is caused by mutations in the NF1 gene on chromosome 17q11.2. Its protein product, neurofibromin, functions as a tumor suppressor and ultimately produces constitutive upregulation of mTOR. TSC is caused by mutations in either the TSC1 (chromosome 9q34) or TSC2 (chromosome 16p.13.3) genes. Their protein products, hamartin and tuberin, respectively, form a dimer that acts via the GAP protein Rheb (Ras homolog enhanced in brain) to directly inhibit mTOR, again resulting in upregulation. Specific inhibitors of mTOR are in clinical use, including sirolimus, everolimus, temsirolimus, and deforolimus. Everolimus has been shown to reduce the volume and appearance of subependymal giant cell astrocytomas (SEGA), facial angiofibromas, and renal angiomyolipomas associated with TSC, with a recent FDA approval for SEGA not suitable for surgical resection. This article reviews the use of mTOR inhibitors in these diseases, which have the potential to be a disease-modifying therapy in these and other conditions.

Oncologic outcomes of sporadic, neurofibromatosis-associated, and radiation-induced malignant peripheral nerve sheath tumors

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNSTs) occur sporadically, after prior radiation therapy (RT), or in association with neurofibromatosis type 1 (NF1). It is controversial whether patients with NF1-associated MPNST have worse outcomes. We investigated the prognostic significance of sporadic, NF1-associated, and RT-induced MPNST.

METHODS

Patients with primary high-grade MPNST from 1982 to 2011 were identified from a prospectively maintained database. Patients with sporadic MPNST were included only if the MPNST was not associated with NF1 or a neurofibroma or if it was immunohistochemically S100-positive.

RESULTS

We studied 105 patients; 42 had NF1-associated tumors, 49 sporadic, and 14 RT-induced. Median age at diagnosis was 38 years. Median follow-up for surviving patients was 4 years. Mean tumor diameter was 5.5 cm for RT-induced tumors and 9.7 cm for NF1-associated and sporadic tumors (P=0.004). In multivariate analysis, factors associated with worse disease-specific survival (DSS) were larger size (HR 1.08; 95% CI 1.04-1.13; P<0.001) and positive margin (HR 3.30; 95% CI 1.74-6.28; P<0.001). Age, gender, site of disease, and S100 staining were not associated with DSS. The 3-year and median DSS were similar for NF1 and sporadic cases; combined 3-year DSS was 64% and median DSS was 8.0 years. For RT-induced tumors, 3-year DSS was 49% and median DSS was 2.4 years. The relationship between RT association and DSS approached statistical significance (HR 2.29; 95% CI 0.93-5.67; P=0.072).

CONCLUSIONS

Margin status and size remain the most important predictors of DSS in patients with MPNST. NF1-associated and sporadic MPNSTs may be associated with improved DSS compared with RT-induced tumors.

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.

A retroperitoneal NF1-independent malignant peripheral nerve sheath tumor with elevated serum CA125: case report and discussion

Malignant peripheral nerve sheath tumors (MPNSTs) are usually located in the trunk, extremities, head, or neck, and most occur with neurofibromatosis type 1 (NF1; von Recklinghausen's disease). No biomarkers have previously been found to be associated with their progression. Retroperitoneal NF1-independent MPNSTs are rare; they are considered to be less aggressive and to have better prognoses compared to NF1-related tumors. Currently, en bloc excision is the only consensus treatment approach. In a 27-year-old male with a giant retroperitoneal MPNST and no stigmata or family history of neurofibromatosis type-1 (NF1), a remarkable elevation of serum CA125 was detected. The high-grade tumor displayed a striking progression: the primary lesion, 25 cm in diameter, recurred in its previous site as a 17-cm MPNST less than 50 days after total excision. Subsequent treatment with microwave ablation and huachansu, a traditional Chinese medication, proved ineffective, and the patient died within 3 months. Our case suggests that retroperitoneal MPNSTs can deteriorate rapidly even if NF1 independent, that aggressive treatment may not benefit large high-grade MPNSTs, and that novel and effective treatment is urgently needed. Our case also suggests the possibility of using serum tumor markers in the early detection and monitoring of MPNSTs.

Malignant peripheral nerve sheath tumors in childhood: 13 cases from a single center

PURPOSE

We aimed to review clinical characteristics, treatment results, and outcome for pediatric patients with malignant peripheral nerve sheath tumors (MPNSTs).

METHODS

Files for 13 children diagnosed with MPNSTs and treated at our hospital between 1988 and 2009 were reviewed for clinical characteristics, treatment results, and outcome.

RESULTS

The median patient age was 11 years (range, 0.16 to 18 y; female/male: 6/7). The most common symptoms were palpable mass (7 of 13) and pain (3 of 13). Four patients had neurofibromatosis type 1. Physical findings at diagnosis were palpable mass (10 of 13), scoliosis (2 of 13), paraplegia/cranial nerve palsy (2 of 13), and stigmas of neurofibromatosis type 1. The primary sites were head and neck (5 of 13), abdomen (3 of 13), chest wall (2 of 13), abdominal wall (2 of 13), and extremities (1 of 13). According to the Intergroup Rhabdomyosarcoma Study system, 5 cases were classified as Intergroup Rhabdomyosarcoma Study group I, 6 were classified as group III, and 2 were classified as group IV. Five-year overall and event-free survival rates were 34.6% (±13.8) and 18.8% (±11.9), respectively. Overall survival rates did not differ upon addition of chemotherapy and/or radiotherapy to the surgery. Five-year survival rates were 42.9% (±18.9) in patients with total resection and 37.5% (±28.6) in patients with partial resection (P=0.08). Overall survival rates did not differ according to stages (P=0.8).

CONCLUSIONS

MPNSTs are rare in childhood and have an unfavorable prognosis. Whereas chemotherapy and/or radiotherapy had no promising effect on overall survival rates, complete resection seems to be the most effective treatment for MPNSTs. Further multicenter studies on the role of chemotherapy and/or radiotherapy for MPNSTs are warranted.

Resectable pediatric nonrhabdomyosarcoma soft tissue sarcoma: which patients benefit from adjuvant radiation therapy and how much?

It remains unclear which children and adolescents with resected nonrhabdomyosarcoma soft tissue sarcoma (NRSTS) benefit from radiation therapy, as well as the optimal dose, volume, and timing of radiotherapy when used with primary surgical resection. This paper reviews the sparse literature from clinical trials and retrospective studies of resected pediatric NRSTS to discern local recurrence rates in relationship to the use of radiation therapy.

Neoplasms associated with germline and somatic NF1 gene mutations

INTRODUCTION

Neurofibromatosis 1 is a tumor predisposition genetic syndrome with autosomal dominant inheritance and virtually 100% penetrance by the age of 5 years. NF1 results from a loss-of-function mutation in the NF1 gene, resulting in decreased levels of neurofibromin in the cell. Neurofibromin is a negative regulator of various intracellular signaling pathways involved in the cellular proliferation. Although the loss of heterozygosity in the NF1 gene may predispose NF1 patients to certain malignancies, additional genetic alterations are a prerequisite for their development. The precise nature of these additional genetic alterations is not well defined, and genetic testing of all malignancies in NF1 patients becomes an essential component of future research in this subset of patients. In addition to germline NF1 mutations, alteration of the somatic NF1 gene is associated with sporadic malignancies such as adenocarcinoma of the colon, myelodysplastic syndrome, and anaplastic astrocytoma.

MATERIALS AND METHODS

A comprehensive English and non-English language search for all articles pertinent to malignancies associated with NF1 was conducted using PubMed, a search engine provided by the U.S. National Library of Medicine and the National Institutes of Health. Key words searched included the following: "malignancies associated with NF1", "tumors associated with NF1", and "NF1 and malignancies". A comprehensive analysis in terms age and mode of presentation, investigation and therapeutic modalities, and outcome of the published data was performed and compared with similar information on the sporadic cases.

RESULTS

Malignancies in NF1 patients typically occur at an earlier age and, with an exception of optic pathway gliomas, certain types of malignancies carry a poor prognosis compared with their sporadic counterparts. Malignancies are the leading cause of death in NF1 patients, resulting in a 10- to 15-year decreased life expectancy compared with the general population.

CONCLUSIONS

The lack of well-defined screening tests for early detection and the nonspecific clinical presentation contributes to a poorer outcome in malignancies associated with NF1. Small study group size, mixed patient population, and a lack of uniformity in reporting research results make comparison of treatment outcome for this group difficult. An International Consensus Meeting to address and recommend best practices for screening, diagnosis, management, and follow-up of malignancies associated with NF1 is needed.

Malignant peripheral nerve sheath tumours of the spine: clinical manifestations, classification, treatment, and prognostic factors

BACKGROUND AND OBJECTIVES

To summarise our experience treating patients with spinal malignant peripheral nerve sheath tumours (MPNSTs).

METHODS

We retrospectively reviewed the records of patients diagnosed with spinal MPNSTs who received surgical treatment from January 1998 to December 2009.

RESULTS

Postoperative follow-up data were available for 14/16 patients with spinal MPNSTs (7 men, 7 women; median age = 44 years [range: 23-68 years]). Eight of 14 (57.1%) patients had primary and 6/14 (42.9%) recurrent MPNSTs. A total of 12/14 (85.7%) patients underwent total tumour resection, whereas 2/14 (14.3%) patients underwent subtotal tumour resection. Malignancies were graded low in 4 (28.6%) and high in 10 (71.1%) cases. A total of 12/14 (85.7%) patients experienced tumour recurrence and 10/14 (71.4%) patients died during the course of follow-up. The 0.5- 1-, 3-, and 5-year survival rates were 64.3, 48.2, 32.1, and 21.4%, respectively. Overall survival was significantly associated with tumour malignant degree (P = 0.012).

CONCLUSION

Diagnosis of spinal MPNSTs should be made with reference to clinical, radiological, and pathological findings. Surgical resection is the best available option for treating spinal MPNST; however, postoperative prognosis is poor.

Soft tissue sarcoma across the age spectrum: a population-based study from the Surveillance Epidemiology and End Results database

BACKGROUND

Soft tissue sarcomas (STS) are a heterogeneous group of mesenchymal malignancies that occur throughout the lifespan. The impact of age on disease features and outcome is unclear.

METHODS

We analyzed the clinical features and outcome of all STS cases registered between 1973 and 2006 in the SEER database.

RESULTS

There were 48,012 cases that met the selection criteria. Individuals less than 20 years of age represented 5.6%, with rhabdomyosarcoma being the most common subtype. In adults, the most common types were Kaposi sarcoma, fibrohistiocytic tumors, and leiomyosarcoma. Rhabdomyosarcoma was the only entity with a median age <20 years. Male predominance (male/female of 1.5:1) was noticed for almost all types of STS, except for alveolar soft part sarcoma and leiomyosarcoma. Tumor stage was similar across different age groups. Younger patients (<50 years) had significantly better survival than older patients (88.8 ± 0.2% vs. 40 ± 0.3%, P < 0.001), but for most histologies the survival decline with advancing age was gradual and did not occur abruptly at the onset of adulthood. The decline in survival with advancing age was particularly significant for rhabdomyosarcoma.

CONCLUSION

With few exceptions, the clinical features of STS are similar in children and adults. However, individuals over 50 years of age have an inferior survival.

Soft tissue sarcomas and central nervous system tumors in children with neurofibromatosis type 1

OBJECTS

We aim to evaluate the characteristics of pediatric patients with neurofibromatosis type 1 (NF1) who developed soft tissue sarcomas (STSs) and central nervous system (CNS) tumors that have been followed up in our center.

MATERIALS AND METHODS

Medical records of children with NF1 were retrospectively analyzed.

RESULTS

There were 78 patients who met at least two diagnostic criteria for NF1. The median age of patients was 10 years (0.5-18), and M/F ratio was 1.3. The prevalance of the optic glioma was 11.5% (n = 9), and one patient with optic glioma also had cystic astrocytoma, one patient had brain stem tumor, and one patient had a CNS tumor (without histopathologic diagnosis). Seven of nine children were ≥ 7 years old at the time of the diagnosis of optic glioma. Visual impairment developed in four patients, and two of them were treated with radiotherapy solely on the basis of evidence of clinical and radiological progression of the tumors. Four patients developed STSs. Two of them had malignant peripheral nerve sheath tumors (MPNST), and the remaining two had bladder rhabdomyosarcoma. Three of the four patients with STSs died with progressive disease.

CONCLUSION

The clinical course of malignancy in NF1 is often different from that of similar tumor types in the general population. Careful follow-up in patients with NF1 is required to enable the early diagnosis of malignancies, and the developments of new targeted therapies are needed for improvement of the outcome for patients of this group, especially with MPNST.

Early outcomes for malignant peripheral nerve sheath tumor treated with chemotherapy

OBJECTIVES

Malignant peripheral nerve sheath tumors (MPNST) are rare soft-tissue sarcomas with a tendency for recurrence and metastasis. Treatment using chemotherapy is controversial, but benefit with some agents has been described. This study aimed to analyze early survival outcomes using doxorubicin and ifosfamide chemotherapy for MPNST.

METHODS

Pathology records at our musculoskeletal tumor center were searched for patients with a new diagnosis of MPNST between 2003 and 2008. Treatment involved surgical resection, radiation, and chemotherapy with doxorubicin and ifosfamide. Ten patients met inclusion criteria, with mean age 40 years (range, 20-70). Four patients had metastatic disease on presentation. Four patients had neurofibromatosis type I (NF1).

RESULTS

Of 6 patients with nonmetastatic disease on presentation, 5 had no evidence of disease post-treatment. The sixth had positive margins after surgery and initially received no further treatment due to noncompliance. Three from this subgroup developed local recurrence, but none developed distant metastases and 1 died of disease at last follow-up. One- and 2-year disease-free survival (DFS) for this subgroup was 80% and 60%, respectively. One- and 2-year overall survival (OS) for the subgroup was 100%. Of 4 patients with metastatic disease on presentation, 2 had no evidence of disease post-treatment. One of these 2 developed local recurrence, but none from the subgroup developed new metastatic disease. Two of these 4 died of disease at last follow-up. One- and 2-year DFS for this subgroup was 100% and 50%, respectively. One- and 2-year OS was 75% and 50%, respectively. Two of the 4 patients presenting with metastatic disease had NF1. All 3 local recurrences and 2 of the 3 deaths in this study occurred in NF1 patients.

CONCLUSIONS

For all patients, when combined with surgery and radiation, chemotherapy using doxorubicin and ifosfamide yielded 57% DFS and 80% OS at 2 years. NF1 patients appeared to have worse outcomes, with a statistically significantly lower DFS than non-NF1 patients. Limitations of this study include a small sample size, retrospective design, and use of different chemotherapy regimens.

Malignant peripheral nerve sheath tumors (MPNST): the Mayo Clinic experience

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNST) are a rare form of soft tissue sarcoma with few studies reporting on patient outcomes and prognostic variables.

METHODS

A retrospective review of 175 patients diagnosed with MPNST from 1985 to 2010 was performed. Patient, tumor, and treatment characteristics were evaluated to identify prognostic variables.

RESULTS

The median age of our study population was 44 years, and 51% were female. Median tumor size was 6 cm, and 61% of patients had high-grade tumors. Tumors were most commonly located on the extremities (45%), then trunk (34%) and head/neck (19%). The majority of patients underwent surgical resection (95%) and adjuvant treatment with chemotherapy (6%), radiation (42%) or both (22%). Margin status was R0 in 69%, R1 in 2%, R2 in 9%, and unknown in 20%. The local recurrence rate was 22%, and 5- and 10-year disease-specific survival (DSS) were 60% and 45%, respectively. On univariate analysis, no predictors for local recurrence were identified. Tumor size ≥ 5 cm, high tumor grade, tumor location, presence of neurofibromatosis type 1, local recurrence, and adjuvant chemotherapy were all associated with DSS. On multivariate analysis, size ≥ 5 cm [hazard ratio (HR)= 6.1, 95% confidence interval (CI) 1.5-25.0], local recurrence (HR = 4.4, 95% CI 1.7-11.4), high tumor grade (HR = 3.8, 95% CI 1.1-13.2), and truncal location (HR = 3.7, 95% CI 1.1-12.7) were poor prognostic indicators for DSS.

CONCLUSIONS

High tumor grade and tumor size ≥ 5 cm predict adverse DSS for MPNST. In the context of a multidisciplinary treatment regimen, local recurrence and survival outcomes at 5 and 10 years were better than previously reported for MPNST.

Definitive radiotherapy for unresectable pediatric and young adult nonrhabdomyosarcoma soft tissue sarcoma

BACKGROUND

Few published articles describe outcomes following definitive radiation for unresectable pediatric and young adult nonrhabdomyosarcoma soft tissue sarcoma (NRSTS). The purpose of this study is to evaluate the prognostic factors, outcomes, and complications in patients age 30 years or younger with NRSTS treated at the University of Florida from 1973 to 2002.

PROCEDURE

Nineteen pediatric and young adult patients with NRSTS were treated with radiotherapy after biopsy. Thirteen patients had high-grade tumors. The median age at radiotherapy was 19.6 years; the median dose was 55.2 Gy. Twelve patients received chemotherapy. Prognostic factors for local recurrence, distant metastases, and survival were analyzed.

RESULTS

Median follow-up was 2.6 years. The 5-year local-control rate was 40%. Nine out of 13 local failures occurred in the absence of metastatic disease. All patients with local failures died of their cancer, and 8 patients died without evidence of distant metastases. There was a trend toward improved local control with low/intermediate-grade tumors. Freedom from distant metastases at 5 years was 68%. Fourteen patients died of their disease. The 5-year overall survival was 37%. There was one grade 4 complication based on NCI Common Terminology Criteria for Adverse Events version 3.

CONCLUSION

Young patients with unresectable NRSTS have a poor outcome thereby justifying current study efforts focused on treatment intensification. By demonstrating that all patients with local recurrence died of disease and more than half of these deaths occurred in the absence of distant spread, these results suggests that improved means of local control may translate into improvement in survival.

Neuro-oncology of Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder with an incidence of about 1:2500 to 1:3000. It is caused by a germline inactivating mutation of the NF1 gene on chromosome 17. Patients with NF1 are at increased risk of developing a variety of tumors of the peripheral and central nervous system, including neurofibromas, plexiform neurofibromas, malignant peripheral nerve sheath tumors, and low-grade gliomas of the optic nerves and other cerebral structures. Rarely, they develop high-grade gliomas. Although they are rare, these hereditary tumor syndromes involving the nervous system must be recognized in patients and their families, as early diagnosis may alter management and ultimately improve outcome. Additional insight into the molecular mechanisms causing these syndromes and their relationship with the clinical features will allow the development and implementation of screening and prevention strategies for these diseases. Management of these lesions is difficult and requires specific skills and the collaborative work of neurosurgeons, radiation therapists, neurologists, and oncologists. Ideally, patients should be managed in comprehensive centers with specific expertise in the management of patients with NF1. This review describes current and developing therapies for managing the neuro-oncologic manifestations of NF1.

Malignant Peripheral Nerve Sheath Tumor of the Vestibulocochlear Nerve and Brainstem

BACKGROUND AND IMPORTANCE

Malignant peripheral nerve sheath tumors are the most common malignant mesenchymal tumors of soft tissues, but they are very rare when found to arise from a cranial nerve and when not in association with neurofibromatosis. These tumors are highly malignant and carry a poor prognosis with survival usually less than 6 months.

CLINICAL PRESENTATION

The authors report the case of a 23-year-old female with no history of phakomatoses, previous irradiation, or known genetic disorders, who presented with a malignant peripheral nerve sheath tumor of the vestibulocochlear nerve and brainstem. Multiple staged skull base approaches were carried out with maximal possible resection. Adjunctive therapies including standard radiation therapy, intensity-modulated radiation therapy, and stereotactic gamma knife radiosurgery were used with an ultimate patient survival of 27 months.

CONCLUSION

To our knowledge, this is the first report describing a patient with a malignant peripheral nerve sheath tumor of the vestibulocochlear nerve and brainstem treated with staged surgical approaches in conjunction with multiple forms of radiotherapy and having a significant survival of more than 2 years.

Recurring Intracranial Malignant Peripheral Nerve Sheath Tumor: Case Report and Systematic Review of the Literature

BACKGROUND AND IMPORTANCE:

To report the clinical presentation and management of an intracranial frontoparietal malignant peripheral nerve sheath tumor (MPNST) and its recurrence in a 6-year-old girl, along with a systematic review of the literature.

CLINICAL PRESENTATION:

A previously healthy 6-year-old girl presented with severe signs of increased intracranial pressure. Magnetic resonance imaging (MRI) revealed a large heterogeneously enhancing mass at the right frontoparietal convexity. The tumor was completely removed, the histological diagnosis was MPNST, and the patient underwent adjuvant radio- and chemotherapy. Fifteen months later, MRI revealed a small local recurrence. After upfront chemotherapy, the recurrence was removed in a radical, ie, true oncological, neuronavigationally guided, en bloc resection, including approximately 1 cm surrounding gray and white matter and overlying dura mater. Neuropathological examination revealed tumor-free margins. The patient again received adjuvant chemotherapy. Four years after diagnosis and 20 months after cessation of adjuvant therapy, there are no signs of tumor recurrence. The literature search resulted in 17 cases of intracranial MPNSTs not associated with cranial nerves. Despite macroscopically complete resection in many cases and adjuvant radio- and chemotherapy, overall survival was poor, with only 5 patients still alive upon publication (including the current patient).

CONCLUSION:

Intracranial MPNSTs not associated with cranial nerves are extremely rare and highly malignant tumors with poor overall survival, probably because of infiltrating growth into surrounding brain tissue. We therefore advocate consideration of nonconventional true oncological en bloc resection when approaching this rare tumor or its recurrence.

Malignant peripheral nerve sheath tumor arising from the greater omentum: case report

Malignant peripheral nerve sheath tumors (MPNSTs) are rare soft tissue tumors that arise from a peripheral nerve or exhibit nerve sheath differentiation. Most of these tumors arise on the trunk, extremities, or head and neck regions; they are very rarely located in the abdominal cavity. The patient was a 71-year-old man who was referred to our hospital for a mass and pain in the right lower abdomen. Abdominal computed tomography revealed a large (9 × 9 cm), well-circumscribed, lobulated, heterogeneously enhanced mass in the pelvis. Exploratory laparotomy revealed a large mass in the greater omentum, and the tumor was completely excised. Histopathological analysis revealed that the tumor was composed of spindle cells with high mitotic activity. On staining the tumor, positive results were obtained for S-100 but negative results were obtained for c-kit, cluster of differentiation (CD)34, α-smooth muscle actin, and desmin. These findings strongly supported a diagnosis of MPNST primarily arising from the greater omentum. To the best of our knowledge, this is the first reported case of an MPNST arising from the greater omentum. In this report, we have described the case of a patient with an MPNST arising from the greater omentum and have discussed the clinical characteristics and management of MPNSTs.

Non-metastatic unresected paediatric non-rhabdomyosarcoma soft tissue sarcomas: results of a pooled analysis from United States and European groups

BACKGROUND

Non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) with initially unresected tumours represent a particular subset of patients with a poor outcome. Various international research groups pooled their data in a joint study in order to investigate prognostic variables and treatment modalities.

METHODS

The study population consisted of 304 patients <21 years old treated between 1980 and 2005 using a multimodality therapeutic strategy.

RESULTS

Synovial sarcoma and malignant peripheral nerve sheath tumour (MPNST) were the most frequent histotypes. Most patients received initial chemotherapy: major responses were recorded in 41% and minor in 16% of cases. Overall survival (OS) was 60.0% and 51.5% at 5 and 10 years, respectively, and it was significantly associated with patient's age, histological subtype, tumour site and size, quality of delayed surgical resection, radiotherapy administration and response to induction chemotherapy. MPNST associated to neurofibromatosis type 1 was the tumour type with the worst rate of response to chemotherapy and the worst outcome.

CONCLUSIONS

In unresected NRSTS patients, radiotherapy and delayed surgery are of crucial importance. Patients who respond to chemotherapy have better chance of survival. However, given the relatively poor prognosis, research on intensive multimodal treatment approaches and novel strategies is warranted.

Factors of influence upon overall survival in the treatment of intracranial MPNSTs. Review of the literature and report of a case

BACKGROUND

Intracranial malignant peripheral nerve sheath tumors are rare entities that carry a poor prognosis. To date, there are no established therapeutic strategies for these tumors.

METHODS

We review the present treatment modalities and present the current therapeutic dilemmas. We perform a statistical analysis to evaluate the prognostic factors for Overall Survival of these patients. Additionally, we present our experience with a 64-year-old man with a MPNST of the left cerebellopontine angle.

RESULTS

To our best knowledge, forty three patients with intracranial MPNSTs, including our case, have been published in the international literature. Our analysis showed gross total resection, radiotherapy and female gender to be beneficial prognostic factors of survival in the univariate analysis. Gross total resection was recognized as the only independent predictor of prolonged Overall Survival. In our case, we performed a gross total resection followed for the first time by stereotactically guided radiotherapy.

CONCLUSION

Considering the results of the statistical analysis and the known advantages of the stereotaxy, we suggest aggressive surgery followed by stereotactically guided radiotherapy as therapy of choice.

First-line chemotherapy for malignant peripheral nerve sheath tumor (MPNST) versus other histological soft tissue sarcoma subtypes and as a prognostic factor for MPNST: an EORTC soft tissue and bone sarcoma group study

BACKGROUND

the role of chemotherapy in advanced malignant peripheral nerve sheath tumor (MPNST) is unclear.

PATIENTS AND METHODS

chemotherapy-naive soft tissue sarcomas (STS) patients treated on 12 pooled nonrandomized and randomized European Organization for Research and Treatment of Cancer Soft Tissue and Bone Sarcoma Group trials were retrospectively analyzed. Clinical outcomes, overall survival, progression-free survival (PFS) and response were determined for MPNST and other STS histotypes and compared. Additionally, prognostic factors within the MPNST population were defined. Studied cofactors were demographics, sarcoma history, disease extent and chemotherapy regimen.

RESULTS

after a median follow-up of 4.1 years, 175 MPNST out of 2675 eligible STS patients were analyzed. Outcome was similar for MPNST versus other STS histotypes, with a response rate, median PFS and overall survival of 21% versus 22%, 17 versus 16 weeks and 48 versus 51 weeks, respectively. Performance status was an independent prognostic factor for overall survival. Chemotherapy regimen was an independent prognostic factor for response (P < 0.0001) and PFS (P = 0.009). Compared with standard first-line doxorubicin, the doxorubicin-ifosfamide regimen had the best response, whereas ifosfamide had the worst prognosis.

CONCLUSION

this series indicates the role of chemotherapy in treatment of advanced MPNST. This first comparison showed similar outcomes for MPNST and other STS histotypes. The apparent superiority of the doxorubicin-ifosfamide regimen justifies further investigations of this combination in randomized trials.

Primary intracranial malignant peripheral nerve sheath tumour responding to chemotherapy

Malignant peripheral nerve sheath tumours (MPNST) are a rare variety of soft tissue sarcomas (STS) arising from major peripheral nerve branches and typically located in the lower extremity, chest wall or the retroperitoneum. It is a biologically aggressive neoplasm for which the treatment of choice is surgery, but usually requires a multimodality approach, having been generally labelled as chemoresistant. We present a case of MPNST located intracranially with a good response to chemotherapy.

Genomic changes in chromosomes 10, 16, and X in malignant peripheral nerve sheath tumors identify a high-risk patient group

PURPOSE

The purpose of this study was to identify genetic aberrations contributing to clinical aggressiveness of malignant peripheral nerve sheath tumors (MPNSTs).

PATIENTS AND METHODS

Samples from 48 MPNSTs and 10 neurofibromas were collected from 51 patients with (n = 31) or without (n = 20) neurofibromatosis type 1 (NF1). Genome-wide DNA copy number changes were assessed by chromosomal and array-based comparative genomic hybridization (CGH) and examined for prognostic significance. For a subset of 20 samples, RNA microarray data were integrated with the genome data to identify potential target genes.

RESULTS

Forty-four (92%) MPNSTs displayed DNA copy number changes (median, 18 changes per tumor; range, 2 to 35 changes). Known frequent chromosomal gains at chromosome arms 8q (69%), 17q (67%), and 7p (52%) and losses from 9p (50%), 11q (48%), and 17p (44%) were confirmed. Additionally, gains at 16p or losses from 10q or Xq identified a high-risk group with only 11% 10-year disease-specific survival (P = .00005). Multivariate analyses including NF1 status, tumor location, size, grade, sex, complete remission, and initial metastatic status showed that the genomic high-risk group was the most significant predictor of poor survival. Several genes whose expression was affected by the DNA copy number aberrations were identified.

CONCLUSION

The presence of specific genetic aberrations was strongly associated with poor survival independent of known clinical risk factors. Conversely, within the total patient cohort with 34% 10-year disease-specific survival, a low-risk group was identified: without changes at chromosomes 10q, 16p, or Xq in their MPNSTs, the patients had 74% 10-year survival.

Inhibition of Eyes Absent Homolog 4 expression induces malignant peripheral nerve sheath tumor necrosis

Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive sarcomas without effective therapeutics. Bioinformatics was used to identify potential therapeutic targets. Paired Box (PAX), Eyes Absent (EYA), Dachsund (DACH), and Sine Oculis (SIX) genes, which form a regulatory interactive network in drosophila, were found to be dysregulated in human MPNST cell lines and solid tumors. We identified a decrease in DACH1 expression, and increases in expression of PAX6, EYA1, EYA2, EYA4, and SIX1- 4. Consistent with the observation that half of MPNSTs develop in neurofibromatosis type 1 patients, subsequent to NF1 mutation, we found that exogenous expression of the NF1-GAP related domain (GRD) normalized DACH1 expression. EYA4 mRNA was elevated more than 100-fold as estimated by quantitative real time PCR in most MPSNT cell lines. In vitro, suppression of EYA4 expression using shRNA reduced cell adhesion and migration and caused cellular necrosis without affecting cell proliferation or apoptotic cell death. MPNST cells expressing sh-EYA4 either failed to form tumors in nude mice or formed very small tumors, with extensive necrosis but similar levels of proliferation and apoptosis as control cells. Our findings identify a role for EYA4 and possibly interacting SIX and DACH proteins in MPNSTs and suggest the EYA4 pathway as a rational therapeutic target.

Current approach to pediatric soft tissue sarcomas

The development of a new soft tissue lesion in an otherwise healthy child, adolescent, or young adult can present many challenges for pediatric or medical oncology teams. Although uncommon, the diagnosis of a soft tissue malignancy should always be considered in the differential diagnosis of persistent pain, even if no mass is palpable. The definitive diagnosis and treatment of a soft tissue mass is aided by timely scans, appropriate biopsy for anatomic and molecular pathology, and a treatment approach guided by the specific diagnosis. Because pediatric soft tissue sarcomas are rare, cooperative groups play a crucial role in defining the standard of care through retrospective series and well-designed prospective clinical trials. Enrollment of newly diagnosed patients in clinical studies should be encouraged in order to continue to improve outcomes and understanding of these rare tumors. This review focuses on the current recommendations for management of sarcomas that typically occur in the soft tissues of pediatric and young adult patients.

Malignant peripheral nerve sheath tumour (MPNST): the clinical implications of cellular signalling pathways

Malignant peripheral nerve sheath tumour (MPNST) is a rare malignancy accounting for 3–10% of all soft tissue sarcomas. Most MPNSTs arise in association with peripheral nerves or deep neurofibromas and may originate from neural crest cells, although the specific cell of origin is uncertain. Approximately half of MPNSTs occur in the setting of neurofibromatosis type 1 (NF1), an autosomal dominant disorder with an incidence of approximately one in 3500 persons; the remainder of MPNSTs develop sporadically. In addition to a variety of clinical manifestations, approximately 8–13% of NF1 patients develop MPNSTs, which are the leading cause of NF1-related mortality. Surgical resection is the mainstay of MPNST clinical management. However, because of invasive growth, propensity to metastasise, and limited sensitivity to chemotherapy and radiation, MPNST has a guarded to poor prognosis. Five-year survival rates of only 20–50% indicate an urgent need for improved therapeutic approaches. Recent work in this field has identified several altered intracellular signal transduction cascades and deregulated tyrosine kinase receptors, posing the possibility of personalised, targeted therapeutics. However, expanded knowledge of MPNST molecular pathobiology will be needed to meaningfully apply such approaches for the benefit of afflicted patients.

Retrospective study of the surgical management and outcome of nonrhabdomyosarcoma soft tissue sarcomas of the groin and axilla in children

PURPOSE

The incidence of pediatric nonrhabdomyosarcoma soft tissue sarcomas (NRSTSs) of the groin and axilla is unknown, and the optimal surgical approach to these patients is unclear.

METHODS

We conducted a retrospective study of patients treated at St Jude Children's Research Hospital from January 1962 to March 2007 for NRSTSs of the groin and axilla. Demographic variables, tumor pathology, clinical management, and outcome were reviewed.

RESULTS

Of the 300 patients treated for NRSTSs, only 10 had tumors of the axilla or groin (6 of whom had synovial sarcoma). Surgical interventions included wide resection of the tumor (n = 7), marginal resection (n = 1), subtotal resection (n = 1), and biopsy only (n = 1). Six patients underwent lymph node sampling; all were negative for tumor. Short- and long-term surgical complications were rare. Four patients received adjuvant chemotherapy (n = 3) and/or radiotherapy (n = 2). At a median follow-up of 8.5 years, 7 of the 10 were surviving free of disease. Two of these patients died of tumor progression (1 with metastases at diagnosis and 1 with an unresectable tumor at diagnosis), and one patient who was free of NRSTS died of secondary breast carcinoma.

CONCLUSIONS

Pediatric NRSTSs of the axilla and groin are rare, but outcomes are similar to those of other patients with NRSTS. Wide local excision of the tumor with preservation of good limb function should be the surgical goal and may be sufficient therapy in some cases.

Current status of sporadic and neurofibromatosis type 1-associated malignant peripheral nerve sheath tumors

Malignant peripheral nerve sheath tumors (MPNSTs) are highly aggressive soft tissue sarcomas that rarely occur in the general population but have a lifetime incidence of 8% to 13% in those with neurofibromatosis type 1 (NF1). Complete surgical resection is the standard treatment for MPNSTs. Unresectable MPNSTs carry a poor prognosis, and survival appears to be worse in NF1-associated tumors than in sporadic tumors. The response rate of MPNSTs to standard chemotherapeutic agents used to treat pediatric and adult soft tissue sarcomas is unknown and is currently undergoing evaluation in a multi-institutional clinical trial. With an increasing understanding of the molecular pathogenesis of MPNSTs, clinical trials with targeted agents have become available and have established that histology-specific trials in this rare malignancy are feasible. This knowledge, coupled with the availability of preclinical MPNST models, likely will accelerate the development of effective treatments for this malignancy.

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.

Oxaliplatin-dacarbazine combination chemotherapy for the treatment of advanced soft tissue sarcoma of the limbs

Background

This study was designed to explore the feasibility, safety, and outcomes of pre-operative oxaliplatin-dacarbazine combination therapy for the treatment of advanced soft tissue sarcoma (STS) of the limb.

Patients and Methods

Between November 2005 and November 2008, 31 patients with advanced limb STS classified with stage IV STS were randomly assigned into experimental or control groups, and both were given 2 cycles of chemotherapy before undergoing surgery. The regimen for the experimental group was oxaliplatin (120 mg/m², d₁) in combination with dacarbazine (175 mg/m², d_1-3), while that for the control group was a standard vincristine, epirubicin, cyclophosphamide therapy. Operations were carried out four weeks after the second chemotherapy cycle, followed by another 2-4 more chemotherapy cycles of the previous regimen.

Results

Following preoperative chemotherapy, the experimental group exhibited a significant improvement in tumor regression compared to controls. Both regimens were well-tolerated, and no significant differences in adverse reactions were noted. At a median follow-up of 24 months, 28 patients were still alive and had normal limb function. The progression free survival rate of the experimental group was significantly higher than that of the control group (10/15 vs. 4/16, p < 0.05).

Conclusion

Oxaliplatin- dacarbazine neoadjuvant/adjuvant chemotherapy improved the prognosis of patients with advanced limb STS in comparison with vincristine, epirubicin, cyclophosphamide combination therapy.

Survival in Malignant Peripheral Nerve Sheath Tumours: A Comparison between Sporadic and Neurofibromatosis Type 1-Associated Tumours

We studied 123 patients with malignant peripheral nerve sheath tumours (MPNSTs) between 1979 and 2002. However, 90 occurred sporadically whereas 33 were associated with neurofibromatosis type 1 (NF1). Survival was calculated using Kaplan-Meier survival curves and we used Cox's proportional hazards model to identify independent prognostic factors. A 5-year survival for 110 nonmetastatic patients was 54%; (33% NF1 and 63% sporadic P = .015). Tumour stage and site were significant prognostic indicators after univariate analysis. After multivariate analysis, however, only NF1 (P = .007) and tumour volume more than 200 m (P = .015) remained independent predictors of poor outcome. We recommend that NF1 be taken into account during MPNST staging. As the survival rate in the NF group was dependant on tumour volume, routine screening of these patients with FDG PET and/or MRI may be warranted, thereby staging and controlling them at the earliest possible opportunity.

How does the Schwann cell lineage form tumors in NF1?

Neurofibromas are benign tumors of peripheral nerve that occur sporadically or in patients with the autosomal dominant tumor predisposition syndrome neurofibromatosis type 1 (NF1). Multiple neurofibroma subtypes exist which differ in their site of occurrence, their association with NF1, and their tendency to undergo transformation to become malignant peripheral nerve sheath tumors (MPNSTs), the most common malignancy associated with NF1. Most NF1 patients carry a constitutional mutation of the NF1 tumor suppressor gene. Neurofibromas develop in these patients when an unknown cell type in the Schwann cell lineage loses its remaining functional NF1 gene and initiates a complex series of interactions with other cell types; these interactions may be influenced by aberrant expression of growth factors and growth factor receptors and the action of modifier genes. Cells within certain neurofibroma subtypes subsequently accumulate additional mutations affecting the p19(ARF)-MDM2-TP53 and p16INK4A-Rb signaling cascades, mutations of other as yet unidentified genes, and amplification of growth factor receptor genes, resulting in their transformation into MPNSTs. These observations have been validated using a variety of transgenic and knockout mouse models that recapitulate neurofibroma and MPNST pathogenesis. A new generation of mouse models is also providing important new insights into the identity of the cell type in the Schwann cell lineage that gives rise to neurofibromas. Our improving understanding of the mechanisms underlying the pathogenesis of neurofibromas and MPNSTs raises intriguing new questions about the origin and pathogenesis of these neoplasms and establishes models for the development of new therapies targeting these neoplasms.

The Neurofibromatosis type 1:A dominantly inherited tumors-predisposing disorder

Neurofibromatosis type I (NF1) is a hereditary multisystem disease involving the skin and nervous system. It is the most common form of autosomal dominant phakomatoses with 100% penetrance but wide phenotypic variability. The NF1 gene is located on chromosome 17q11.2 and encodes for a tumour suppressor protein. Because affected individuals have an increased risk of tumor formation, this disorder is classified as inherited cancer syndrome. The risk of malignancies in NF1 affected patients is estimated to be 5–15% higher than in the general population. We reviewed clinical aspects and genetic mechanisms of tumorigenesis in NF1 affected patients.

Neurofibromatosis type 1 revisited

Neurofibromatosis type 1 (NF1) is an autosomal dominant condition with a worldwide incidence of approximately 1 per 2500 to 3000 individuals. Caused by a germ-line-inactivating mutation in the NF1 gene on chromosome 17, the disease is associated with increased morbidity and mortality. In the past several years, significant progress has been made in standardizing management of the major clinical features of neurofibromatosis type 1. Moreover, improved understanding of how the neurofibromatosis type 1 protein, neurofibromin, regulates cell growth recently provided insight into the pathogenesis of the disease and has led to the development of new therapies. In this review, we describe the clinical manifestations, recent molecular and genetic findings, and current and developing therapies for managing clinical problems associated with neurofibromatosis type 1.

Metastatic malignant peripheral nerve sheath tumor in a newborn

Malignant peripheral nerve sheath tumors are rare tumors, especially in the newborn period. Diagnosis is based on clinical findings, radiography, and fine needle biopsy or tissue sampling. Ideal management is controversial and extremely difficult. The survival rate is extremely low. We present a case of a newborn in which this tumor is diagnosed in the first few days of life as an ulcerating tumor imbedded in the entire forefoot with already metastatic spread to the lymph nodes and abdomen. Questions arose on the best treatment in postpartum life. Below the knee amputation was performed for nursing purposes, but eventually a no-intention-to treat policy was chosen by the multidisciplinary team and parents. Detection of soft tissue tumors in the prenatal period is difficult and not as easy as for other structural defects. Would prenatal detection have changed the course of life of this young infant? Will future opportunities for detection of soft tissue tumors occur? Diagnostic and therapeutic considerations are discussed alongside the present literature.