Cytomorphology of metastatic malignant peripheral nerve sheath tumour present in pleural fluid: Case study and literature review.

The cytomorphology of MPNST in effusion specimens is rarely described. In this paper, the detailed cytopathological and immunohistochemical characteristics of metastatic MPNST has been described in pleural effusion. Patients' medical history and the judicious utilization of ancillary studies contribute to ensure precise cytological diagnoses. The cytomorphology of malignant peripheral nerve sheath tumour (MPNST) in effusion specimens can be diagnostically challenging. The author presents detailed cytopathological and immunohistochemical characteristics of a case of metastatic MPNST in pleural effusion.

Malignant vestibular schwannoma with intracerebral metastasis.

BACKGROUND: Malignant change in vestibular schwannoma is rare and intracranial metastatic deposits have not been reported. CLINICAL PRESENTATION: We report the case of a 64 year old woman with a benign vestibular schwannoma who underwent translabyrinthine excision in 1996 and Gamma Knife® radiosurgery (Elekta AB, Stockholm, Sweden) (GKRS) in 2006. She presents 10 years after GKRS with progressive neurological deterioration. Histopathologic analysis confirms a malignant peripheral nerve sheath tumour, WHO grade IV with subsequent metastatic spread to the left thalamus confirmed on biopsy. CONCLUSION: We report a rare case of a vestibular schwannoma metastasizing with histological confirmation. It also reminds us of malignant conversion of a benign vestibular schwannoma following GKRS and subsequent aggressive behaviour, with poor prognosis.

Malignant peripheral nerve sheath tumours in a patient with Neurofibromatosis-1.

Malignant peripheral nerve sheath tumour (MPNST) is an uncommon type of soft tissue tumour which most commonly arises in the setting of Neurofibromatosis-1 (NF-1) or in the presence of another nerve sheath tumour. NF-1 is an autosomal dominant syndrome which is diagnosed based on clinical criteria. People suffering from NF-1 are at a higher risk of developing tumours, especially MPNST. MPNST can occur anywhere along the distribution of nerve roots but most commonly involves the limbs and trunk. The prognosis of MPNST in the setting of NF-1 is grave as the distant metastasis develops earlier than non-syndromic cases. Pre-operative diagnosis is difficult as there is no gold standard radiologic technique or characteristic radiological features. The diagnosis is established after histological evaluation supplemented by immunohistochemistry of the tumour tissue. We present a case of a 38-year-old female, a known case of NF-1, who presented with a single, irregular, cystic swelling in the left flank which was increasing in size. The patient underwent complete surgical excision of a 6cm tumour which was diagnosed as MPNST after histopathological examination. The rare nature of this tumour makes the diagnosis and treatment extremely hard. Awareness regarding this disease should be increased so that proper treatment plans can be made.

PRAME expression in spindle cell melanoma, malignant peripheral nerve sheath tumour, and other cutaneous sarcomatoid neoplasms: a comparative analysis.

Diagnosis of spindle cell/sarcomatoid melanoma may be challenging due to frequent loss of expression of melanocytic marker(s) and histomorphologic resemblance to various mesenchymal tumours, particularly malignant peripheral nerve sheath tumour (MPNST). Overexpression of PReferentially expressed Antigen in MElanoma (PRAME) supports a diagnosis of melanoma when evaluating challenging melanocytic tumours. PRAME expression in MPNST and other cutaneous sarcomatoid neoplasms, however, has not been well characterised. We aimed to determine the utility of PRAME immunostain in distinguishing spindle cell melanoma from MPNST and other sarcomatoid mimics. PRAME expression was scored by extent (0 to 4+) and intensity (0 to 3) of staining. A strong positive correlation was observed between the extent and intensity scores (r = 0.84). An extent score of 4+, defined by staining in 76-100% of tumour cells, was seen in 56% (23/41) of spindle cell melanomas, 18% (7/38) of MPNSTs, 15% (4/27) of cutaneous sarcomatoid squamous cell carcinomas (SCCs), 33% (5/15) of poorly differentiated cutaneous angiosarcomas, 12% (4/33) of atypical fibroxanthomas (AFXs), 4% (1/25) of pleomorphic dermal sarcomas (PDSs), and none (0/16) of the high-grade cutaneous leiomyosarcomas. A significant difference was found between spindle cell melanoma and all other examined sarcomatoid neoplasms except angiosarcoma. While diffuse (and often strong) PRAME expression is more frequently observed in spindle cell melanoma than MPNST, sarcomatoid SCC, AFX, PDS, and high-grade leiomyosarcoma, its limited sensitivity and specificity caution against its use as a standalone diagnostic marker. PRAME may complement other epigenetic or lineage-specific markers and should only be used as part of an immunohistochemical panel when evaluating these sarcomatoid neoplasms.

CDX2 expression in malignant peripheral nerve sheath tumour: a potential diagnostic pitfall associated with PRC2 inactivation.

AIMS: Malignant peripheral nerve sheath tumour (MPNST) is a soft tissue sarcoma that exhibits features of Schwann cell differentiation. Heterologous, often mesenchymal-type differentiation occurs in a subset of MPNST, while glandular morphology also is encountered in rare cases. We observed in MPNST unanticipated expression of CDX2, a transcription factor that regulates intestinal epithelial differentiation, and aimed to further characterize this phenomenon. METHODS/RESULTS: Expression of CDX2 was assessed by immunohistochemistry in a total of 32 high-grade MPNSTs lacking morphological evidence of epithelial differentiation, including twelve tumours (38%) that developed in the setting of neurofibromatosis and four (13%) in the setting of prior radiation therapy. CDX2 was expressed by 14 of 32 MPNSTs (44%), wherein immunoreactivity, varying from weak to strong, was present in 2-95% of neoplastic spindle cells (median 10%, mean 23%). Notably, CDX2 expression was limited to tumours with PRC2 inactivation (22/32; 69%), as evidenced immunohistochemically by diffuse loss of trimethylated histone H3K27. Analysing publicly available RNA-sequencing data from twelve MPNST cell lines, two of which are clonally related, we observed CDX2 expression in all six PRC2-inactivated cell lines, while CDX2 expression was negligible in six cell lines with intact PRC2, amounting to a 58-fold increase in CDX2 expression on average with PRC2 inactivation. CONCLUSIONS: CDX2 is expressed in a subset of MPNSTs, even in the absence of morphological evidence of epithelial differentiation. CDX2 expression in MPNST is strongly associated with underlying PRC2 inactivation.

Malignant peripheral nerve sheath tumour of the oral and maxillofacial region-A systematic review.

To integrate the available data published on malignant peripheral nerve sheath tumours (MPNST) of the oral and maxillofacial region. Searches in Embase, PubMed, Web of Science and Scopus were conducted for the identification of case reports/case series in English language. The risk of bias was assessed using the Joanna Briggs Institute tool. Outcomes were evaluated by Cox regression and Kaplan-Meier methods. A total of 306 articles were retrieved, 50 of which reporting 57 MPNST were included. The lesion showed a predilection for the mandible (n = 18/31.57%) of middle-aged adults (~40.5 years) with a male/female ratio of 1.1:1. The individuals were mostly symptomatic with a mean evolution time of 9.6 months. Surgical removal plus adjuvant therapy (especially radiotherapy) was the main approach (51.86%). Recurrence was reported in 39.62% of cases. Nodal and distant metastases were identified in 28.26% and 26.66% of cases, respectively. The 2-year cumulative survival rate was 55%. Independent predictors of poor survival were the presence of neurofibromatosis type 1 (p = 0.04) and distant metastases (p = 0.004). The diagnosis of MPNST is challenging due to the variety of its clinical and histopathological presentations. Local aggressiveness and the potential for metastases are common outcomes of this neoplasm.

Morphology of the entering and exiting nerve as a differentiating feature of benign from malignant peripheral nerve sheath tumours of the brachial plexus.

OBJECTIVE: To identify if morphology of the entering and exiting nerve involved by a nerve sheath tumour in the brachial plexus can help differentiate between benign (B) and malignant (M) peripheral nerve sheath tumours (PNSTs). MATERIALS AND METHODS: Retrospective review of 85 patients with histologically confirmed primary PNSTs of the brachial plexus over a 12.5-year period. Clinical data and all available MRI studies were independently evaluated by 2 consultant musculoskeletal radiologists blinded to the final histopathological diagnosis assessing for maximal lesion dimension, visibility and morphology of the entering and exiting nerve, and other well-documented features of PNSTs. RESULTS: The study included 47 males and 38 females with mean age 46.7 years (range, 8-81 years). There were 73 BPNSTs and 12 MPNSTs. The entering nerve was not identified in 5 (7%), was normal in 17 (23%), was tapered in 38 (52%) and showed lobular enlargement in 13 (18%) BPNSTs compared with 0 (0%), 0 (0%), 2 (17%) and 10 (83%) MPNSTs respectively. The exiting nerve was not identified in 5 (7%), was normal in 20 (27%), was tapered in 42 (58%) and showed lobular enlargement in 6 (8%) BPNSTs compared with 4 (33%), 0 (0%), 2 (17%) and 6 (50%) MPNSTs respectively. Increasing tumour size, entering and exiting nerve morphology and suspected MRI diagnosis were statistically significant differentiators between BPNST and MPNST (p < 0.001). IOC for nerve status was poor to fair but improved to good if normal/tapered appearance were considered together with improved specificity of 81-91% for BPNST and sensitivity of 75-83%. CONCLUSIONS: Morphology of the adjacent nerve is a useful additional MRI feature for distinguishing BPNST from MPNST of the brachial plexus.

[Malignant Triton tumour: A case report]. / Tumeur Triton maligne : à propos d'un cas.

Malignant Triton tumour (MTT) is a subtype of malignant peripheral nerve sheaths tumour (MPNST) with exclusive heterologous rhabdomyosarcomatous contingent. MTT is rare and of poor prognosis. This entity illustrates the great heterogeneity of MPNST, the diagnosis of which is difficult in the absence of a specific marker, especially in sporadic forms. Although MTT preferentially develop in patients with type 1 neurofibromatosis, sporadic cases may occur. We herein present a case of MTT of the left arm, occurring in a 74-year-old patient, without clinical context of NF1. The fast-growing tumour reached 9.2cm of greater dimension at the time of surgical excision. Histology showed a spindle cell sarcoma with rhabdoid cell areas expressing myogenin. In the absence of neural crest markers expression, the diagnosis of MPNST was based on a significant loss of expression of the histone 3 tri-methylated lysine 27, a classical although not specific epigenetic mark for this sarcoma group, and on the identification of the heterologous rhabdomyosarcomatous contingent, previously described in the context of MTT.

Surgical management of peripheral nerve sheath tumours in children, with special consideration of neurofibromatoses.

INTRODUCTION: Peripheral nerve sheath tumours in children are a rare and heterogeneous group, consisting mostly of benign tumours as well as malignant neoplasms. Especially in the paediatric population, diagnostics and indication for therapy pose relevant challenges for neurosurgeons and paediatric neurologists alike. Most paediatric cases that need surgical intervention are associated to neurofibromatosis type 1 (NF1). METHODS: We retrospectively reviewed all paediatric cases treated at the Department of Neurosurgery in Tübingen between 2006 and 2017 for peripheral nerve sheath tumours. We analysed clinical signs, symptoms, histology, association to an underlying phacomatosis and sensory/motor function. RESULTS: Of the 82 identified patients, the majority had NF1 (76.8%). Nine children bore a sporadic tumour without underlying phacomatosis (11%), 8 had NF2 (9.8%) and 2 schwannomatosis (2.4%), A total of 168 surgical interventions were performed, and 206 tumours were removed. Indication for surgery was in most instances significant tumour growth (45.2%) followed by pain (33.9%). New deficits led to surgery in 12.5% of interventions; malignancy was suspected in 8.3%. Histopathology revealed mostly neurofibromas (82.5%), divided into cutaneous neurofibromas (10.7%), infiltrating plexiform neurofibromas (25.7%) and peripheral nerve-born neurofibromas (46.1%). 12.1% of tumours were schwannomas, 2.9% MPNST, 1.5% ganglioneuroma (n = 3) and 1 hybrid-neurofibroma and perineurinoma each. Leading symptoms, such as pain and motor and sensory deficits, improved after 125/166 interventions (74.4%), remained unchanged following 39 interventions (23.2%) and worsened in 4 occasions (2.4%). CONCLUSION: Surgery is safe and effective for (neurofibromatosis associated) peripheral nerve sheath tumours in the paediatric population; however, management needs a multidisciplinary setting. We propose early surgical resection in paediatric patients with peripheral nerve sheath tumours with significant growth, or pain, or motor deficit, or suspected malignancy.

Malignant peripheral nerve sheath tumours in magnetic resonance imaging: primary and recurrent tumour appearance, post-treatment changes, and metastases.

PURPOSE: To analyse the appearance of primary and recurrent malignant peripheral nerve sheath tumours (MPNSTs) in magnetic resonance imaging (MRI) with a focus on configuration, and to assess the occurrence of loco-regional post-treatment changes and metastases during post-treatment follow-up. MATERIAL AND METHODS: Twenty patients with histologically proven MPNST underwent post-treatment 1.5 T MRI. Primary and recurrent MPNSTs were examined for configuration, contrast enhancement, extent, and signal intensity in MRI. Loco-regional post-treatment changes and information on metastases were extracted from the follow-up. RESULTS: MPNSTs occurred most often in the extremities (p = 0.006). Twenty per cent (n = 4) of the patients developed recurrences, with a total of 24 lesions. Recurrent MPNSTs were significantly smaller than primary MPNSTs (p = 0.003). Primary MPNSTs mostly occurred unifocally as multilobulated or ovoid and heterogeneous lesions with mostly well-defined borders. Recurrent MPNSTs purely occurred multifocally as mostly nodular (p < 0.001), multilobulated, or ovoid lesions. 80%, 65% and 30% of the patients showed post-treatment subcutaneous oedema (p = 0.002 to 0.03), muscle oedema (p = 0.02), and seroma, respectively. Twenty-five per cent (n = 5) of patients presented metastases during follow-up. The relative risk in patients with recurrences to develop lung or lymph node metastases is eightfold (p = 0.056). CONCLUSIONS: While primary MPNSTs mostly appear unifocally as multilobulated or ovoid lesions, recurrent MPNSTs purely occur multifocally as mostly nodular lesions. Subcutaneous and muscle oedema are very common loco-regional post-treatment changes. Patients with recurrences have a higher risk for lung and lymph node metastases.

Novel enriched pathways in superficial malignant peripheral nerve sheath tumours and spindle/desmoplastic melanomas.

Superficial malignant peripheral nerve sheath tumour (MPNST) is a rare, soft tissue neoplasm that shares morphological features and some molecular events with spindle/desmoplastic melanoma (SDM). Herein, we sought to identify molecular targets for therapy by using targeted RNA/DNA sequencing and gene expression of key immunological players. DNA and RNA from formalin-fixed paraffin-embedded tissue were extracted and processed. Massive high-throughput deep parallel sequencing was performed with the Oncomine comprehensive panel, enabling detection of relevant single-nucleotide variants, copy number variations, gene fusions and indels for 143 unique genes on the Ion torrent sequencer for clinical trial research programmes. Gene expression analysis was carried out with a customized 770-gene expression panel combining markers for 24 different immune cell types and 30 common cancer antigens, including key checkpoint blockade genes analysed with the Ncounter system. Fifty-one patients (SDM, 16/11; MPNST, 24; male, n = 37; female, n = 16) had sufficient DNA and RNA for testing. NF1 deleterious mutations and/or deep/homozygous deletions were identified in 73% of MPNSTs and 67% of SDMs, with 50% of the mutations involving the RAS-binding domain. Inactivating/deleterious mutations of TSC1/TSC2 were identified in 40% and 41% of MPNSTs and SDMs, respectively. Activating mutations affecting the EGFR-like and the negative regulatory domains of NOTCH1 and KDR (VEGFR2) were identified in 45% and 40% of SDMs and in 30% and 8% of MPNSTs, respectively. Differential gene expression and gene clustering analysis showed significantly perturbed immune pathway components, including nuclear factor-κB (NF-κB), JAK-STAT, and CXCL12-CXCR4, and differentially expressed CD274 and CTLA4, in both SDM and MPNST. Angiogenesis (KDR and NOTCH1) and mammalian target of rapamycin complex (mTORC) pathways offer a rationale for anti-angiogenic and selective mTORC inhibition as treatment strategies for MPNST and SDM. Cytokines and the JAK-STAT, TNF and NF-κB axes were perturbed in both SDM and MPNST. These pathways have been targeted in haematological malignancies and present promising targets for these tumours. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Evaluation of eight melanocytic and neural crest-associated markers in a well-characterised series of 124 malignant peripheral nerve sheath tumours (MPNST): useful to distinguish MPNST from melanoma?

AIMS: The diagnosis of malignant peripheral nerve sheath tumour (MPNST) may be challenging, especially in the sporadic setting. Owing to the lack of specific histological criteria, immunohistochemical and molecular diagnostic markers, several differential diagnoses must be considered, especially melanoma. Indeed, although S100 protein usually stains melanoma, other melanocytic markers are often negative, especially in spindle cell/desmoplastic types. This pattern of immunoreactivity resembles that of some nerve-derived tumours such as MPNST. Owing to their different clinical behaviours and therapeutic implications, accurate identification of these two different tumours is crucial. METHODS AND RESULTS: S100, SOX10, KBA62, MITF, HMB45, Melan-A, tyrosinase PNL2 and BRAF-V600E immunostaining was performed in a pathologically and genetically well-characterised cohort of primary MPNST (n = 124), including 66 (53%) NF1-associated tumours. Sox10 and KBA62 expression were found, respectively, in 102 (84%) and in 101 (83%) MPNST, whereas S100 was expressed in 64 cases (52%). We observed an increased loss of S100 with increasing histological grade (P = 0.0052). We found Melan-A expression in 14% (n = 17) of all MPNST, occurring in 82% (n = 14) of cases in an NF1 context. Six per cent (n = 8) of MPNST showed tyrosinase positivity, including seven (87%) NF1-associated. MITF expression was found in 10 (8%) MPNST. None expressed PNL2, HMB45 or BRAF-V600E. CONCLUSION: MPNST (in NF1 and a sporadic setting) can quite often be positive for Melan-A, tyrosinase and MITF. Pathologists should be cognisant of these exceptions to prevent confusion with melanoma.

Extraskeletal osteosarcoma: MDM2 and H3K27me3 analysis of 19 cases suggest disease heterogeneity.

AIMS: Extraskeletal osteosarcoma (ESOS) is a sarcoma in the non-skeletal tissue that directly produces neoplastic osteoid or bone. De-differentiated liposarcoma (DDLPS) and malignant peripheral nerve sheath tumour (MPNST) are the two most common types of sarcoma that can harbour heterologous osteosarcomatous differentiation. We aimed to determine the potential relationship of ESOS to DDLPS and MPNST. METHODS AND RESULTS: We investigated MDM2 and H3K27me3 status in 19 cases of ESOS, two of which contained a low-grade component. The ESOS affected deep soft tissues (n = 10), superficial soft tissues (n = 3) and organs (n = 6). Among 10 deep soft-tissue ESOS, six showed MDM2 amplification, four of which also harboured CDK4 co-amplification. Both ESOS with a low-grade component showed co-amplification for MDM2 and CDK4. Among the six organ-based ESOS three giant cell-rich ESOS showed an H3K27me3 deficiency (one in primary and two in metastatic sites). Using targeted next generation sequencing, an H3K27me3-deficient ESOS showed EED homozygous deletion, while none of the three showed alterations in NF1, CDKN2A or SUZ12 genes. During median follow-up of 20 months, all six patients with MDM2-amplified ESOS lived for 3-103 months, while two of the three patients with H3K27me3-deficient ESOS died from this disease in 4 and 20 months, respectively. CONCLUSION: We demonstrate that ESOS may include at least two small subsets: an MDM2-amplified deep soft-tissue ESOS (which may be related to DDLPS) and an H3K27me3-deficient organ-based ESOS (which is probably unrelated to MPNST). Larger studies are required to validate the present observations and investigate the clinical implications of such subcategorisation.

Monitoring of plexiform neurofibroma in children and adolescents with neurofibromatosis type 1 by [18 F]FDG-PET imaging. Is it of value in asymptomatic patients?

PURPOSE: About 10% of patients with neurofibromatosis type 1 (NF-1) develop malignant peripheral nerve sheath tumours (MPNST) mostly arising in plexiform neurofibroma (PN); 15% of MPNST arise in children and adolescents. 2-[18 F]fluoro-2-deoxy-d-glucose ([18 F]FDG)-PET (where PET is positron emission tomography) is a sensitive method in differentiating PN and MPNST in symptomatic patients with NF-1. This study assesses the value of [18 F]FDG-PET imaging in detecting malignant transformation in symptomatic and asymptomatic children with PN. METHODS: Forty-one patients with NF-1 and extensive PN underwent prospective [18 F]FDG imaging from 2003 to 2014. Thirty-two of the patients were asymptomatic. PET data, together with histological results and clinical course were re-evaluated retrospectively. Maximum standardised uptake values (SUVmax) and lesion-to-liver ratio were assessed. RESULTS: A total of 104 examinations were performed. Mean age at first PET was 13.5 years (2.6-22.6). Eight patients had at least one malignant lesion; four of these patients were asymptomatic. Two of four symptomatic patients died, while all patients with asymptomatic malignant lesions are alive. All malignant tumours could be identified by PET imaging in both symptomatic and asymptomatic patients. All lesions judged as benign by [18 F]FDG imaging and clinical judgment were either histologically benign if removed or remained clinically silent during follow-up. SUVmax of malignant and benign lesions overlapped, but no malignant lesion showed FDG uptake ≤3.15. Asymptomatic malignant lesions were detected with a sensitivity of 100%, a negative predictive value of 100% and a specificity of 45.1%. CONCLUSION: Malignant transformation of PN also occurs in asymptomatic children and adolescents. Detection of MPNST at early stages could increase the possibility of oncologically curative resections.

Immunohistochemistry for trimethylated H3K27 in the diagnosis of malignant peripheral nerve sheath tumours.

AIMS: The diagnosis of a malignant peripheral nerve sheath tumour (MPNST) can be challenging, as the morphological criteria and existing immunohistochemical markers are not entirely specific. The recent discovery of frequent inactivation of polycomb repressive complex 2 in MPNSTs suggests that immunohistochemical detection of histone 3 trimethylated on lysine 27 (H3K27me3) could be of diagnostic help. This study aimed to clarify the utility of this marker. METHODS AND RESULTS: We performed immunostaining studies, with monoclonal (C36B11) and polyclonal antibodies in parallel. With the monoclonal antibody, 56% of 54 conventional MPNSTs showed complete loss of staining, whereas 17% showed mosaic loss and 28% showed intact staining. Three MPNSTs showed a novel geographical pattern of complete loss. All three epithelioid MPNSTs retained intact staining. Among 232 non-MPNSTs, only two (0.9%) showed complete loss of staining. Mosaic loss was observed in 38% of non-MPNSTs, whereas the remaining 61% retained intact staining. For conventional MPNSTs, complete loss of H3K27me3 was significantly associated with a higher TNM stage (P = 0.013), a deeper location (P = 0.004), and the presence of heterologous differentiation (P = 0.003). Polyclonal antibodies did not recognize 34% of cases that showed complete loss with the use of monoclonal antibodies. CONCLUSIONS: We confirmed that complete loss of H3K27me3 immunohistochemical staining is moderately sensitive and highly specific for MPNSTs. In contrast to prior studies, we found that mosaic loss of H3K27me3 staining is non-specific, and caution that such a pattern should not be considered to be diagnostic. We recommend the use of a monoclonal antibody to obtain better performance.

Characterisation of malignant peripheral nerve sheath tumours in neurofibromatosis-1 using heterogeneity analysis of 18F-FDG PET.

PURPOSE: Measurement of heterogeneity in 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) images is reported to improve tumour phenotyping and response assessment in a number of cancers. We aimed to determine whether measurements of 18F-FDG heterogeneity could improve differentiation of benign symptomatic neurofibromas from malignant peripheral nerve sheath tumours (MPNSTs). METHODS: 18F-FDG PET data from a cohort of 54 patients (24 female, 30 male, mean age 35.1 years) with neurofibromatosis-1 (NF1), and clinically suspected malignant transformation of neurofibromas into MPNSTs, were included. Scans were performed to a standard clinical protocol at 1.5 and 4 h post-injection. Six first-order [including three standardised uptake value (SUV) parameters], four second-order (derived from grey-level co-occurrence matrices) and four high-order (derived from neighbourhood grey-tone difference matrices) statistical features were calculated from tumour volumes of interest. Each patient had histological verification or at least 5 years clinical follow-up as the reference standard with regards to the characterisation of tumours as benign (n = 30) or malignant (n = 24). RESULTS: There was a significant difference between benign and malignant tumours for all six first-order parameters (at 1.5 and 4 h; p < 0.0001), for second-order entropy (only at 4 h) and for all high-order features (at 1.5 h and 4 h, except contrast at 4 h; p < 0.0001-0.047). Similarly, the area under the receiver operating characteristic curves was high (0.669-0.997, p < 0.05) for the same features as well as 1.5-h second-order entropy. No first-, second- or high-order feature performed better than maximum SUV (SUVmax) at differentiating benign from malignant tumours. CONCLUSIONS: 18F-FDG uptake in MPNSTs is higher than benign symptomatic neurofibromas, as defined by SUV parameters, and more heterogeneous, as defined by first- and high-order heterogeneity parameters. However, heterogeneity analysis does not improve on SUVmax discriminative performance.

Metastatic malignant peripheral nerve sheath tumour presenting as a spontaneous extradural haematoma - A case report.

Malignant peripheral nerve sheath tumours may arise from any cranial or somatic nerve. The median survival with best therapy is 49 months. The present case reports a patient with an MPNST that exhibited an unusually indolent behaviour. Besides this, the patient developed a dural metastasis from the lesion and presented with a spontaneous extra-dural haematoma. This has not been reported hitherto in literature.

Malignant peripheral nerve sheath tumour of penis.

Malignant peripheral nerve sheath tumour (MPNST) is a rare variety of soft tissue sarcoma that originates from Schwann cells or pluripotent cells of neural crest origin. They have historically been difficult tumours to diagnose and treat. Surgery is the mainstay of treatment with a goal to achieve negative margins. Despite aggressive surgery and adjuvant therapy, the prognosis of patients with MPNST remains poor. MPNST arising from penis is a very rare entity; thus, it presents a diagnostic and therapeutic challenge. We present a case of penile MPNST in a 38-year-old man in the absence of neurofibromatosis treated with surgery followed by post-operative radiotherapy to a dose of 60 Gray in 30 fractions and adjuvant chemotherapy with ifosfamide and adriamycin.

Syndrome-associated soft tissue tumours.

Soft tissue neoplasms may be associated with a variety of genetic disorders and malformation syndromes, especially when they arise in children, adolescents and early adulthood. This review summarizes the principal histopathological types of soft tissue tumours which occur in various syndromes, with an emphasis on pathological features, genetic aspects and considerations for the diagnostic pathologist.

[Malignant peripheral nerve sheath tumour of the infra-orbital nerve]. / Tumor maligno de vaina de nervio periférico afectando al nervio infraorbitario.

A malignant peripheral nerve sheath tumour (MPNST) is an uncommon neoplasm that rarely involves the head and neck region. It is even more infrequent for these tumours to affect cranial nerves. We report the case of a 53-year-old man who presented a MPNST involving the infra-orbital nerve, which extended through the orbit and the base of the skull, progressing intracranially. Histological studies identified the tumour as an MPNST. Response to radiotherapy was not complete and radical surgical resection was impossible, so the patient died 10months later. This rare case of MPNST with intracranial involvement illustrates the dismal prognosis for patients with these lesions. Prognosis is poor because of the difficulty of performing radical surgery with free margins in these locations.