Diagnosis Of Malignant Peripheral Nerve Sheath Tumor Research Articles

Malignant peripheral nerve sheath tumor of retroperitoneum involving small and large bowel: A rare case report

Malignant peripheral nerve sheath tumors (MPNSTs) are rare and aggressive, soft-tissue sarcomas having a high rate of recurrence which largely occur in the extremities and the head-and-neck region. Gastrointestinal (GI) MPNSTs are rare. To date, only a few cases have been reported. We report the case of a 50-year-old man who presented with pain and a lump in his abdomen for 1 year. Clinically, the case was thought to be retroperitoneal neurofibroma. A computed tomography scan revealed an intra-abdominal large well-defined lobulated mass predominantly on the left side. Exploratory laparotomy and resection of the tumor were done as large and small bowel mesentery masses. Histopathological examination showed a spindle cell neoplasm composed of interlacing fascicles of slender to plump spindle cells with wavy buckled nuclei. Cells showed moderate to marked anisonucleosis with hyperchromatic and vesicular nuclei with prominent nucleoli along with many pleomorphic cells with multiple nuclei and many mitosis. The tumor seemed to be infiltrating the wall of the small bowel and colon. On immunohistochemistry, tumor cells were positive for vimentin, focally positive for S100, and negative for smooth muscle actin. Thus, the diagnosis of MPNST was confirmed. This case highlights that, although rare, the possibility of MPNST of retroperitoneum should be considered as a differential diagnosis in an unexplored retroperitoneal mass.

Expanding a precision medicine platform for malignant peripheral nerve sheath tumors: New patient-derived orthotopic xenografts, cell lines and tumor entities.

Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive soft-tissue sarcomas with a poor survival rate, presenting either sporadically or in the context of neurofibromatosis type 1 (NF1). The histological diagnosis of MPNSTs can be challenging, with different tumors exhibiting great histological and marker expression overlap. This heterogeneity could be partly responsible for the observed disparity in treatment response due to the inherent diversity of the preclinical models used. For several years, our group has been generating a large patient-derived orthotopic xenograft (PDOX) MPNST platform for identifying new precision medicine treatments. Herein, we describe the expansion of this platform using six primary tumors clinically diagnosed as MPNSTs, from which we obtained six additional PDOX mouse models and three cell lines, thus generating three pairs of in vitro-in vivo models. We extensively characterized these tumors and derived preclinical models, including genomic, epigenomic, and histological analyses. Tumors were reclassified after these analyses: three remained as MPNSTs (two being classic MPNSTs), one was a melanoma, another was a neurotrophic tyrosine receptor kinase (NTRK)-rearranged spindle cell neoplasm, and, finally, the last was an unclassifiable tumor bearing neurofibromin-2 (NF2) inactivation, a neuroblastoma RAS viral oncogene homolog (NRAS) oncogenic mutation, and a SWI/SNF-related matrix-associated actin-dependent regulator of chromatin (SMARCA4) heterozygous truncated variant. New cell lines and PDOXs faithfully recapitulated histology, marker expression, and genomic characteristics of the primary tumors. The diversity in tumor identity and their specific associated genomic alterations impacted treatment responses obtained when we used the new cell lines for testing compounds against known altered pathways in MPNSTs. In summary, we present here an extension of our MPNST precision medicine platform, with new PDOXs and cell lines, including tumor entities confounded as MPNSTs in a real clinical scenario. This platform may constitute a useful tool for obtaining correct preclinical information to guide MPNST clinical trials.

A distal ileum malignant peripheral nerve sheath tumour after abdominal radiation therapy: case report of a rare tumour.

Malignant peripheral nerve sheath tumours (MPNSTs) are malignant tumours arising from a peripheral nerve or displaying nerve sheath differentiation. Most MPNSTs are found on the head, body trunk and extremities, whereas cases in the gastrointestinal are extremely rare. About half arise in neurofibromatosis type 1 patients and 10% arise post-irradiation. This is probably the first small bowel MPNST post-radiation therapy case reported. A 72-year-old female who received radiotherapy 30years ago for cervical cancer was admitted with progressive abdominal pain and weight loss. Computed tomography revealed a mass with inhomogeneous enhancement in the lumen of the small intestine. Tumour excision was performed with ileocecal and sigmoid colon resection due to suspicion for peripheral tissue invasion. Histopathological examination revealed spindle-shaped cells with focal cartilage differentiation. Together with immunochemistry stain showing complete loss of H3K27me3, a final diagnosis of MPNST was made. The patient is presently under regular follow-ups, and has remained disease-free for 24months.

Analysis of demographic characteristics of malignant peripheral nerve sheath tumor in adults: A National Cancer Database study.

e23555 Background: Malignant peripheral nerve sheath tumor (MPNST) is a rare cancer involving the peripheral nerve sheath. Even though the 5-year post-surgical resection survival rate is only 30 to 40%, the epidemiology is not well understood, and looking at trends in demographics could provide insight into factors potentially contributing to poor prognosis. A previous National Cancer Database (NCDB) study investigated demographics in pediatric patients with MPNST. This study analyzed NCDB data to investigate the demographics of adults with MPNST. Methods: Adult patients with a histologic diagnosis of MPNST were retrospectively examined in a cohort analysis using demographic information from the NCDB from 2004 – 2020 (N = 414). Regression analysis was used to describe incidence trends. Demographics (age, sex, race, Hispanic origin, income, insurance status, area of residence, facility type, distance from facility, and Charlson-Deyo score) were explored through descriptive statistics. Palliative care enrollment and mortality rate was examined. Results: 414 patients with age > 18 were identified in the NCDB database with a confirmed diagnosis of MPNST between the years 2004 – 2020. There was a slight increase in incidence of patients diagnosed per year (R2 = 0.254). The average age of diagnosis was 47.0 years (SD = 17.2, range = 19 – 88 years) with more males (51.4%) affected than females (48.6%). The most common primary sites were the retroperitoneum (32.4%), spinal cord (24.4%), and cranial nerves (15.0%). A majority of individuals (82.6%) had Charlson-Deyo comorbidity scores of 0. Individuals most commonly affected were White (79.7%) or Black (14.3%), and non-Hispanic (87.4%). Patients most commonly were in the top quartile of household income (31.6%), had private insurance (53.6%), lived in metropolitan counties (83.8%), and received treatment at an academic/research program (62.2%). Patients lived on average 61.6 miles (SD = 145.7, range = 0.5 – 1454.9) from the facility. The 90-day mortality rate post-surgery was 10.5%. The overwhelming majority of patients did not receive palliative care (94.4%). Conclusions: This is the first NCDB analysis on the demographics of MPNST in adults, providing information that bridges the gap in knowledge. This analysis showed that the retroperitoneum was the most common tumor site, and that the average age of diagnosis was 47 years, consistent with previous reports. Patients were most likely to be White, non-Hispanic, upper quartile income earners, privately insured, treated at an academic facility, and live in metropolitan counties. With the majority of patients receiving no palliative care, it’s possible that palliative care is underutilized and may benefit MPNST patients given the poor prognosis. Additional research on the relationship between socioeconomic status and palliative care access may provide information on this discrepancy.

Case of Malignant Peripheral Nerve Sheath Tumor (MPNST) of Lung

Malignant peripheral nerve sheath tumor (MPNST) is very unusual type of soft tissue sarcoma (STS) and occurs mostly in patients of neurofibromatosis. The occurrence of MPNST in lung is particularly rare. Only very rarely cases have been reported till date in absence of history of neurofibromatosis. We are reporting such case in a 34 year old female who presented with complains of chest pain, breathlessness and nonproductive cough since 3 months. Microscopic examination revealed a malignant spindle cell tumor of low grade histology. Immunohistochemistry (IHC) was performed which was positive for vimentin and actin and negative for desmin and S- 100. Final diagnosis of MPNST was made on the basis of morphological appearance and IHC. Patient was treated with neoadjuvant chemotherapy ifosfamide and adriamycin for four cycles, followed by surgical excision. At present patient is on regular follow up for one year post treatment. Keywords: lung cancer; Malignant peripheral nerve sheath tumors.

Malignant spindle cell tumor of the anal canal, what are the differential diagnoses?

Malignant peripheral nerve sheath tumor (MPNST) is an uncommon tumor. Here, we report a case of rectal MPNST. The patient was a 75 year old man with symptoms and signs of a mass protruded from anus. There was no evidence of neurofibromatosis type 1 in him or his family. Primary diagnosis was hemorrhoid. Biopsy was taken. The microscopic examination revealed spindle cells with large and hyperchromatic nuclei. Mitotic figures were numerous. Routine and ancillary techniques confirmed the diagnosis of MPNST. MPNST should be distinguished from more common lesions encountered at this anatomic site such as hemorrhoid, malignant melanoma, sarcomatoid carcinoma, and gastrointestinal stromal tumor.

Malignant peripheral nerve sheath tumor of temporoparietal region of brain mimicking as glioma: A rare case report

Malignant peripheral nerve sheath tumor (MPNST) is exceedingly rare to occur intracerebrally. The incidence of this subtype is 0.001%. Their typical origin is from peripheral nerves of the limbs, trunk, and lumbar and brachial plexuses. It carries a poor prognosis despite aggressive management due to high chances of local recurrence. We present a case of MPNST occurring intracerebrally in a 60-year-old male patient. Imaging showed a 63 × 74 × 46 mm mass lesion in the left temporoparietal region with mass effect. The patient underwent left temporoparietal craniotomy with maximum gross dissection of the tumor. Histopathology was suggestive of spindle cell neoplasm. On immunohistochemistry, cells were positive for S-100 and SOX-10, which are consistent with the diagnosis of MPNST. The post-operative contrast-enhanced magnetic resonance imaging brain showed gross residual disease. Post-operative radiotherapy was given of intensity-modulated radiation therapy and chemotherapy of doxorubicin and ifosfamide.

Case report of malignant peripheral nerve sheath tumor of parotid in a patient with neurofibromatosis type 1

<p>Malignant peripheral nerve sheath tumor (MPNST) refers to spindle cell sarcomas arising from or separating in the direction of cells of the peripheral nerve sheath. The MPNST of the parotid gland is an extremely rare tumor, accounts for <5% of all soft tissue sarcomas, and carries a poor prognosis. Diagnosis of MPNSTs is usually based on histopathology aided by IHC, which reflects the Schwann cell differentiation in this neoplasm. Approximately 50-90% of MPNSTs are positive for S-100 protein. A 56-year-old male presented with right parotid swelling for 3 months and incomplete right eye closure. The patient was diagnosed with neurofibromatosis 1 (NF-1) and pulmonary tuberculosis in the past. On Examination, a hard, tender swelling measuring 5×4 cm involving the right parotid gland and right grade 2 LMN facial palsy was noted. Histopathology was suggestive of a MPNST.</p><p><strong> </strong></p>

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 57MPNST were included. The lesion showed a predilection for the mandible (n=18/31.57%) of middle-aged adults (~40.5years) with a male/female ratio of 1.1:1. The individuals were mostly symptomatic with a mean evolution time of 9.6months. 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.

First documented case of intracranial falcine malignant peripheral nerve sheath tumor: illustrative case.

BACKGROUNDThe authors reported the first documented case of intracranial extraaxial nonneurofibromatosis type 1–related nontriton malignant peripheral nerve sheath tumor (MPNST) originating from the falx cerebri.OBSERVATIONSA 34-year-old man with headache, short-term memory deficit, postural instability, and blurred vision presented with a large heterogenous contrast-enhanced intraventricular cystic lesion originating from the free margin of the falx cerebri. The patient received surgery using the right posterior interhemispheric approach. Gross total resection was performed, and the inferior border of the falx cerebri was resected. The postoperative course was uneventful. Histological examination revealed hypercellular foci of neoplastic spindle cells with hyperchromatic and wavy nuclei. Hence, a diagnosis of MPNST was made based on concomitant immunochemistry findings, including mouse double minute 2 homolog focal positivity and geographic loss of H3K27me3. The patient received adjuvant radiotherapy, and recurrence was not observed.LESSONSIntracranial MPNSTs are extremely rare tumors, typically originating from the cranial nerves in the posterior cranial fossa. An even rarer variant of these tumors, referred to as malignant intracerebral nerve sheath tumors, may directly arise from the brain parenchyma. The authors reported the first case of an intracranial MPNST originating from the dura mater of the falx cerebri, acting as an extraaxial lesion with prevalent expansion in the right ventricle.

Sporadic Malignant Perineurioma: A Rare Diagnosis Among Malignant Peripheral Nerve Sheath Tumors

Malignant perineurioma is a rare subset of malignant peripheral nerve sheath tumors (MPNSTs) with ultrastructural and immunohistochemical features of perineurial differentiation, distinguishing it from other MPNSTs, which typically demonstrate Schwannian features. The clinical course and prognosis of this rare tumor is not well defined. The electronic medical records were searched for patients with a diagnosis of MPNST. Patients with a pathologic diagnosis of malignant perineurioma or MPNST with perineurial features were identified and further evaluated. Five patients with malignant perineurioma, or MPNST with perineurial features, were identified. Four patients (2 male and 2 female) were included with tumors associated with a common digital nerve, small muscular branch to the deltoid, sciatic nerve, and accessory nerve. One patient with the pathology diagnosis meeting inclusion criteria was excluded, as no clinical information was available for this patient. Patients in our series presented at varied stages of disease. Clinical courses after diagnosis of malignant perineurioma, where follow-up was available, were largely uncomplicated with regard to recurrence and metastatic disease. Careful follow-up is indicated, and further work is needed to characterize the clinical course of these rare tumors.

Malignant peripheral nerve sheath tumor of mesocolon: A rare case

Malignant peripheral nerve sheath tumor (MPNST) is a soft-tissue sarcoma arising from or differentiating toward peripheral nerve sheath cells. It accounts for 5%–10% of soft-tissue sarcomas. The most common sites of origin are proximal portion of upper, lower limbs and trunk. MPNST arising from the nerve plexus of gastrointestinal tract is extremely rare, and only very few cases have been reported in literature. In this report, we are describing a case of MPNST from mesocolon. An 82-year-old male presented to hospital with complaint of pain abdomen and feeling of lump on the left side of lower abdomen for the past 2 months. On contrast-enhanced computed tomography (CECT) of chest and abdomen, there was 15 cm × 10 cm mass palpable in left lumbar region without ascites and multiple random subpleural nodules in bilateral lung. Intraoperatively, there was 15 cm × 10 cm hard irregular mass in left paracolic gutter infiltrating mesentry of descending colon. Left hemicolectomy was performed with end-to-end anastomosis. Histopathological examination revealed malignant peripheral nerve sheath tumor, and on immunohistochemistry, tumor cells were positive for S-100 and negative for C-kit and Smooth Muscle Actin (SMA). The patient was started on tamoxifen in view of old age and lung metastasis. The patient is on follow-up from 2 years with stable disease. In this report, we highlight the possibility of clinical differential diagnosis of MPNST arising from mesocolon should be kept while dealing with mesenchymal tumors of colon. Radical surgery with negative margins is required for achieving palliation, and adjuvant tamoxifen could offer advantage in patient who cannot tolerate chemotherapy.

Review and update in the diagnosis of peripheral nerve sheath tumors.

Although tumors with nerve sheath differentiation are vast, the main clinically significant problems faced by the pathologist are the separation of malignant peripheral nerve sheath tumors (MPNSTs) from histologic mimics, the diagnosis of neurofibromatous neoplasms with atypical features, and the separation of cutaneous neurofibromatous neoplasms from melanoma. This review briefly discusses a variety of common nerve sheath tumors and summarizes recent advances on these diagnostic fronts. Much of recent work has focused on abnormalities in polycomb repressive complex 2, and the ways in which these abnormalities may be exploited in the diagnosis of MPNSTs. Progress has been made in the diagnostic and clinical understanding of atypical neurofibromatous neoplasms and low-grade MPNSTs. A number of reports have explored the diagnostic distinction between cutaneous neurofibroma and melanoma. New discoveries show promise in the diagnosis of peripheral nerve sheath tumors, but challenges - old and new - remain.

Personal and Familial Malignancy History in Patients with Malignant Peripheral Nerve Sheath Tumors with a Focus on Sporadic Tumors

Malignant peripheral nerve sheath tumors (MPNSTs) occur sporadically, in patients with neurofibromatosis 1, and in patients with prior radiation therapy. The incidence of unrelated prior malignancies and family history of malignancy in patients with MPNSTs has not been previously described. A retrospective search for cases of MPNSTs at our institution for the years 1994-2019 was performed. The electronic medical record was reviewed for documentation of personal and family history of malignancies. The study included 331 patients. Of patients, 301 had documentation of their personal history of prior unrelated malignancies; 70 (23.3%) of these patients had a personal history of an unrelated previous malignancy. Of patients, 285 had information in the chart regarding family history of cancer; 210 (73.7%) of these patients had a family history of malignancy. Of patients, 145 had sporadic MPNSTs, 118 had neurofibromatosis 1-associated MPNSTs, 31 had radiation-induced MPNSTs, and 37 were missing this information. Among the sporadic cases, 29 had a personal history of an unrelated prior malignancy, and 10 developed an unrelated malignancy following diagnosis of MPNST. A family history of malignancy was present in 109 patients. There was a trend toward longer time to recurrence, time to metastasis, and overall survival in patients with sporadic MPNSTs and negative personal and family histories compared with patients with positive personal or family histories or both. Patients with sporadic MPNSTs had a high incidence of personal and family history of malignancy. The genetics associated with sporadic MPNSTs include RAS and p53 mutations, which are found in multiple oncologic processes and tumor-forming syndromes. This suggests an underlying genetic predisposition to formation of malignancies, including MPNSTs.

Incidence of second malignancies in individuals diagnosed with malignant peripheral nerve sheath tumors.

The incidence of malignant peripheral nerve sheath tumors (MPNSTs) is low in the general population, although individuals with Neurofibromatosis Type I (NF1) are particularly susceptible. These tumors generally have a high probability of metastasis. The rate and types of second malignancies (SMNs) after a primary diagnosis of MPNST are not well characterized. We aimed to quantify the rate of SMNs among individuals with a first primary MPNST using population-based data. We estimated age-standardized incidence rates (SIRs) for SMNs among 1,579 primary MPNST cases between ages 0-85+ using SEER 18 (2000-2015). We estimated incidence rate ratios (IRRs) and 95% confidence intervals (95% CI) for SMNs in MPNST cases compared with general population rates. We conducted sex-stratified and age-restricted analyses (< 30years at diagnosis). Seven percent (108/1579) of MPNST cases developed a SMN (SIR of 4635 cases/million). Compared to the general population, MPNST cases were more likely to develop SMNs (IRR: 29.3; 95% CI 23.8-34.8) and had a much higher rate of second MPNSTs (IRR: 15,992.9; 95% CI 9594.5-22,391.3). Aside from a second MPNST, second cancers were frequently diagnosed in the breast, lung, skin, and soft tissue in females and were myeloid and skin malignancies in males. When restricted to < 30years of age, second MPNSTs were the most common cancers diagnosed. The rate of SMNs among MPNST cases is tremendously higher than that observed among individuals with other cancers, particularly for second MPNSTs. These findings suggest rates of SMNs may also be higher in NF1 individuals.

Malignant Peripheral Nerve Sheath Tumor and Hypertrophic Osteopathy in a Bitch

Background: Malignant peripheral nerve sheath tumors (MPNSTs) are rare, aggressive, relapsing, metastatic cutaneous neoplasms of mesenchymal origin. So far, no account on the association of this disease with hypertrophic osteopathy (HO) in dogs is available in the literature. Current theories on the possible causes of HO suggest that this disease may be triggered by a primary neoplasm as well as by its metastasis. The objective of this work is to report the clinical, cytological, radiographic, histopathological, and immunohistochemical aspects of a dog affected by MPNST and HO.Case: A 13-year-old female mongrel dog was presented with a history of ulcerated nodular lesion on the skin of the flank. Several ulcerated and non-ulcerated tumors were observed on the thorax, neck, and head at the physical exam. Cytological examination of the nodules revealed presence of mesenchymal cells with a malignant aspect. Complete blood count revealed anemia. There were no alterations in the biochemical tests performed. Thoracic radiographs showed presence of a nodular interstitial pattern in the cranial, medial, and caudal lobes of the lungs. To improve quality of life of the patient, the veterinary team opted for surgical excision of the tumoral ulcerations. Slight claudication in the pelvic limbs was noticed prior to the surgery. Histopathological analyses of the excised nodules verified the existence of malignant mesenchymal neoplasia, which was categorized as peripheral nerve sheath tumor after immunohistochemical examination. Additional cutaneous tumors emerged after surgical excision, along with increased claudication, edema, and pain in the legs. Complete blood count revealed persistent anemia, lymphopenia, monocytosis, and neutrophilia. Radiographs showed an increase in the number and size of the nodules. Radiography of the limbs showed presence of palisading periosteal reaction, and increased radiopacity and volume in the adjacent soft tissues. Doxorubicin and vincristine were administered, but the patient died one week after commencement of the treatment.Discussion: Cytology suggested presence of a malignant neoplasm of mesenchymal origin, and the histopathological and immunohistochemical exams substantiated the diagnosis of malignant peripheral nerve sheath tumor. Macroscopic and histopathological examinations revealed characteristics similar to those described for MPNST in the literature. Positive immunohistochemical reactions for the markers NSE and CD56 determined the diagnosis of MPNST in spite of being negative for S-100, which could represent a consequence of variability in expression and cell differentiation. MPNST exhibits a variable distribution among breeds; it is more predominant in male and elder dogs. Animals exhibiting neoplastic lesions in the thorax, abdomen, head and neck show a high incidence of metastasis after surgical removal of these lesions. The clinical signs of MPNST were unspecific; the alterations observed in the four limbs were observed concomitantly with the diagnosis of hypertrophic osteopathy (HO), and could be due to this condition rather than MPNSC. Histopathological analysis of the pulmonary neoplasms was not possible. However, there is strong suspicion that the pulmonary lesions were a consequence of MPNSC metastasis, which could be the underlying cause of the reemergence of the cutaneous nodules. We believe that HO was caused by the thoracic tumors because the clinical signs became more intense after the increase in the nodules found in the lungs. The difficult diagnosis of MPNSC could be the reason for this type of tumor is rarely identified. MPNSC should always be included in the differential diagnosis for cutaneous tumors, and the possibility that HO represents a consequence of these tumors should be considered.

2652 Primary Malignant Peripheral Nerve Sheath Tumor of Small Bowel and Colon Presenting With Metastases to Bone, Lung, Liver, Spleen, and Brain

INTRODUCTION: Malignant Peripheral Nerve Sheath Tumor (MPNST) is a rare diagnosis, with an incidence of 1:100,000 per year and 4–10% of soft tissue sarcoma, contains properties both neural crest cells and mesenchymal cells. Gastrointestinal MPNSTs are rare disease conditions with only 10 cases reported worldwide in the literature. CASE DESCRIPTION/METHODS: A 71-year old Portuguese male, presented with 8-week history of abdominal pain, anorexia with 20Ib weight loss. Vital signs were normal. On physical examination, a firm, tender, fixed abdominal mass in the RLQ was palpated. CT scan of the abdomen showed a 10 cm necrotic mass on the right side of the abdomen with communication to the small bowel was detected with a suggestion of a walled off perforation. Colonoscopy revealed a flattening of the terminal ileum suggesting an extrinsic compression. Biopsy of tumor consisting of mixed spindle and pleomorphic cells with focal rhabdoid features, high grade nuclear features and brisk mitotic activity. A week later, he presented with symptoms of small bowel obstruction, the CT scan at this time showed a 8 cm left sided abdominal mass with communication to the small bowel with dilation of the jejunum suggesting a new partial obstruction in addition. The patient underwent a palliative debulking of the tumor. Multiple large obstructive masses were found in the Ligament of Treitz,significant portion of the small bowel, right colon, left upper quadrant and omentum. For palliation purposes, these masses were resected and anastomosis was performed. Gross examination of the surgical specimens revealed grayish-tan cystic masses filled with brownish tan hemorrhagic material. Histology of the masses were similr to previous mass. On immunohistochemistry, showed patchy weak S100 immunoreactivity and focal BCL-2 and Neuron Specific Enolase stain immunoreactivity. Ki-67 proliferation index was 70%. The pathologic diagnosis of MPNST was established. He developed multiple bone, pulmonary, liver, splenic and hemorrhagic brain metastases. He died under hospice care within six months of his initial presentation. DISCUSSION: MPNST, occurs mostly in association with Neurofibromatosis Type 1 (8–13%). The tumor typically originates from the nerve sheaths of the major nerves in the extremities (40%), trunk/ retroperitoneal (38%) and head and neck region (21%). However, recent case reports have also documented MPNST of the liver, thyroid gland, skin, eighth cranial nerve and rarely the greater omentum without a history of radiation or NF1.

Can we differentiate malignant peripheral nerve sheath tumor from benign neurofibroma without invasive sampling

One of the most important benign tumors in neurofibromatosis type 1 (NF1) is plexiform neurofibroma, and there is a risk of developing malignant peripheral nerve sheath tumor (MPNST) throughout life approximately 10%. However lesion characterization by anatomical imaging methods are not possible. Because of that most of cases goes to biopsy. Using of fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) for lesion characterization can be helpful in NF1 patients. We aimed to present an example of the efficacy of FDG-PET/CT in distinguishing benign neurofibroma from MPNST. A 6-year-old male patient who had NF1 admitted to emergency service due to high fever. Acute upper respiratory tract infection was diagnosed; antipyretic and abundant fluid intake was suggested. When high fever continued, the patient referred to our hospital on detection of axillary lymphadenopathy. Leukocytosis was detected in patient's blood count. Sedimentation was 54 mm/h, C-reactive protein 166 g/L, and lactate dehydrogenase 276U/L. Blood and throat cultures did not show pathogenic bacteria. In serological tests, VZV-IgG, EBV-VCA-IgG, and CMV-IgG were avidite positive; Hepatitis B Ag, Anti-HIV, Anti-HAV IgG and IgM, Anti-HCV, EBV-VCA IgM, and VZV-IgM were negative. Based on these results, cervical and thoracic contrast-enhanced computed tomography was performed on preliminary diagnosis of MPNST. Solid lesions with rounded margins, large one being 49 mm in size, that extend from superior mediastinum to posterior mediastinum, left axillary region, and left part of neck were detected, and they were surrounding the vascular structures. Since neurofibroma, MPNST, and lymphoma could not be distinguished, patient referred to FDG-PET/CT scanning. In FDG-PET/CT, highest lesion maximum standardized uptake value (SUVmax) was 1.5; SUVmax lesion/SUVmax liver 1.0, and SUVmax/ SUV mean liver 1.5. Biopsy from mediastinal and axillary region did not have LN structure and was positive for S-100 immunostaining, and patient was diagnosed as benign neurofibroma. We believe that there is no need for biopsy in lesions considered benign based on FDG-PET/CT parameters.

Synchronous Development of Multicentric Malignant Peripheral Nerve Sheath Tumors: Institutional Review

Malignant peripheral nerve sheath tumors (MPNSTs) are rare soft tissue sarcomas, with approximately 50% occurring in patients diagnosed with neurofibromatosis type 1 (NF-1). NF-1 occurs in approximately 1/3000 individuals, and given that the lifetime prevalence of MPNST is estimated at 8%-13%, synchronous development of separate MPNSTs is plausible. We sought to report the incidence of synchronous MPNST in a cohort of pathology-proven cases since1994. Records since 1994 were queried and identified 192 patients with pathology-proven MPNST. Medical records of these patients were reviewed to search for patients with synchronous MPNSTs. Retrospective review of 192 patients treated for MPNST at our institution (including 71 patients with NF-1) revealed only 1 patient with synchronous MPNSTs. A 48-year-old woman with NF-1 presented with progressive right upper and lower extremity pain and radicular symptoms. Biopsies of right sciatic and median nerve lesions revealed high-grade MPNST, and she underwent radiotherapy and complete resection of both masses. Due to initial nonspecific biopsy results and patient preference, treatment of the median nerve lesion was delayed by 8 months. She did not have recurrence of her disease at the 18-month follow-up. Synchronous development of MPNST is unusual, with an incidence of 1.4% in our cohort of NF-1 patients with MPNSTs. Given the reported incidence of synchronous MPNST, the rate of malignant transformation in NF-1 may be overestimated. However, heightened suspicion for malignant transformation should continue in patients harboring a diagnosis of MPNST.

Racial/ethnic disparities and incidence of malignant peripheral nerve sheath tumors: results from the Surveillance, Epidemiology, and End Results Program, 2000-2014.

Malignant peripheral nerve sheath tumors (MPNSTs) are rare tumors, generally high-grade, and comprise ~ 5-10% of soft tissue sarcomas. Over two-thirds of MPNSTs metastasize, and upwards of 40% clinically recur. Etiologic risk factors for MPNSTs are historically understudied. There is evidence to suggest MPNST incidence differs across racial/ethnic groups in pediatric populations. Therefore, we sought to estimate differences in MPNST incidence by race/ethnicity among all ages in the United States. Incidence data were obtained from the Surveillance, Epidemiology, and End Results (SEER-18) Program, 2000-2014. Race/ethnicity was categorized as: White; Black; Asian; Other; and Latino/a ("Spanish-Hispanic-Latino"). Latino/a included all races, while all other categories excluded those identified as Latino/a. Age-adjusted incidence rate ratios (IRR) and 95% confidence intervals (CIs) were generated in SEER-STAT (v8.3.4). We estimated incidence rates among all ages, and among those diagnosed < 25and ≥ 25years. MPNST cases were abstracted from SEER-18 (n = 1047). Among all age groups, Blacks experienced an elevated incidence of MPNSTs compared to Whites (IRRBlacks=1.26, 95% CI 1.04-1.50). Asian and Latinos/as experienced lower incidences compared to Whites (IRRAsians=0.78, 95% CI 0.61-0.99; IRRLatinos/as=0.84, 95% CI 0.69-1.02). In subgroup analyses, no statistically significant associations with MPNSTs were identified among cases diagnosed < 25years of age, whereas the associations observed among all age groups were prominent among those diagnosed ≥ 25years of age. Incidence rates of MPNSTs were highest in Blacks compared to Whites and other minority groups. This study suggests specific patterns exist in terms of race/ethnicity and age at diagnosis of MPNSTs.