A Clinicopathologic Study of Head and Neck Malignant Peripheral Nerve Sheath Tumors

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Extranodal Follicular Dendritic Cell Sarcoma of the Head and Neck Region: A Clinicopathological Study of 7 Cases

Background. Follicular dendritic cell (FDC) sarcoma is a rare neoplasm arising from follicular dendritic cells (FDCs). It can be nodal or extranodal. Histological diagnosis of extranodal FDC sarcoma in the head and neck region is challenging and a significant percentage are misdiagnosed. Objectives. To report clinicopathological features of head and neck extranodal FDC sarcoma cases and discuss differential diagnoses. Methods. Seven head and neck extranodal FDC sarcomas were retrieved and clinicopathological features were noted. Results. Two tumors each involved parapharyngeal space and tonsil while remaining cases involved the parotid, soft tissue of neck and oropharynx. Age range was 12 to 79 years (mean and median age were 40 and 44 years respectively) and there was a male predilection (6 males: 1 female). All showed spindle to ovoid cells arranged in fascicles, whorls and/or storiform pattern. Mitoses ranged from 3 to 20/mm2. All tumors expressed CD21 and CD23. Two patients died of their disease at 9 and 16 months. Both had tumors larger than 5 cm with ≥10 mitoses/mm2. Three patients were alive at 12, 44 and 184 months. Conclusions. There was a distinct male predominance in our cohort. FDC sarcoma should be included in the differential diagnosis of spindle cell extranodal neoplasms in the head and neck with a whorled growth pattern and intratumoral lymphocytes. Head and neck region tumors show similar clinicopathologic characteristics as their counterparts at other locations with potential for aggressive behavior especially in tumors greater than 5 cm in size and with high mitotic rates.

Neurofibromatosis Type 1-Associated Malignant Peripheral Nerve Sheath Tumor in the Nasal Cavity

Malignant peripheral nerve sheath tumors (MPNSTs) are rare soft tissue sarcomas, with 50% of cases associated with type 1 neurofibromatosis (NF-1). A 27-year-old male patient was referred to our department with an extended right nasal cavity MPNST. The lesion extended to the skull base, intracranial, parapharyngeal space, and infratemporal fossa. NF-1 was also confirmed by a neurologist. The patient was negative for distant metastases. Due to the tumor's proximity to vital structures, it was decided to treat it with chemotherapy and radiotherapy. Nasal cavity MPNSTs are particularly uncommon, with few reported cases. They should be included in the differential diagnosis of nasal masses or recurrent nosebleeds, particularly in patients with NF-1. Careful follow-up is essential to detect early recurrence, which contributes to a better prognosis.

Non-squamous Laryngeal Cancer

The pathology of non-squamous carcinoma of the larynx is broad and there is a wide differential diagnosis. The most common presenting symptoms for laryngeal malignancies, both squamous and non-squamous, are hoarseness and dyspnea. Presentation with persistent or worsening symptoms and a submucosal lesion should raise suspicion for a non-squamous malignancy of the larynx. Accurate histology determines the most appropriate treatment and has an impact on prognosis.

OUP accepted manuscript

Malignant peripheral nerve sheath tumors are defined as malignant tumors arising from or differentiating toward the cells of the peripheral nerve sheath. They occur in about 8–16% within the head and neck region. Morphologically, some malignant tumors look like malignant peripheral nerve sheath tumors, particularly in the head and neck location; however, immunohistochemistry have a great contribution to distinguish between them. This case report is on a 45-year-old woman with a malignant peripheral nerve sheath tumor located in the sino-nasal tract.

Update on MR Imaging of Soft Tissue Tumors of Head and Neck

This article reviews soft tissue tumors of the head and neck following the 2020 revision of WHO Classification of Soft Tissue and Bone Tumours. Common soft tissue tumors in the head and neck and tumors are discussed, along with newly added entities to the classification system. Salient clinical and imaging features that may allow for improved diagnostic accuracy or to narrow the imaging differential diagnosis are covered. Advanced imaging techniques are discussed, with a focus on diffusion-weighted and dynamic contrast imaging and their potential to help characterize soft tissue tumors and aid in distinguishing malignant from benign tumors.

Recurrent malignant peripheral nerve sheath tumor of the parietal scalp

Malignant peripheral nerve sheath tumors (MPNSTs) are a rare and aggressive subtype of sarcomas defined by their neural origin. Head and neck manifestations are particularly uncommon. Challenges exist in diagnosis, management, and recurrence. Achieving local control, particularly in the head and neck region, is difficult. We present a patient with a rapidly enlarging MPNST on the right parietal calvarium shortly after resection of a right vagus nerve MPNST. Recommendation was made for excision and reconstruction with a local advancement flap followed by radiation therapy. Local control with good aesthetic outcome was achieved by applying recommended surgical and oncologic principles.

Giant Malignant Peripheral Nerve Sheath Tumor of the Scalp: Case Report and Review of the Literature

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNSTs) are rare nervous system tumors that rarely appear on the scalp. About half of the scalp MPNSTs described in the literature have reached giant dimensions at the time of diagnosis. The surgical treatment is the gold standard for this type of tumor. Some authors suggest adjuvant radiotherapy for local tumor control, although there is uncertainty about its advantages and its use is not without risks.

CASE DESCRIPTION

We present the case of a 31-year-old man who presented with a large necrotic scalp tumor of the left frontoparietal convexity. magnetic resonance imaging showed a large extra-axial tumor, measuring 17 x 17 x 8 cm, centered on the soft tissues, with skull erosion and signs of dural invasion, although with no intradural component. The tumor was surgically removed and the osteocutaneous defect was reconstructed with a latissimus dorsi muscle free flap. The anatomopathologic diagnosis was MPNST. The patient then underwent adjuvant radiotherapy. After 7 months he developed a progressive right hemiparesis and magnetic resonance imaging showed results compatible with cerebral radiation necrosis. This motor deficit improved with corticotherapy. After 9 months the patient went back to his home country and was subsequently lost to follow-up.

CONCLUSIONS

Giant MPNSTs of the scalp are highly aggressive lesions that should primarily be treated in a surgical fashion. Although adjuvant radiotherapy has been used routinely for local tumor control, there is uncertainty about its advantages.

Mixed malignant peripheral nerve sheath tumor in the inguinal region: a case report

Malignant peripheral nerve sheath tumor (MPNST) is a rare malignant soft tissue tumor that accounts for approximately 5% of all soft tissue sarcomas. This tumor originates from the peripheral nerves and occurs mainly in the limbs, head and neck, and spine. As a more aggressive tumor, it has higher recurrence and metastasis rates, and patient prognosis is poor. MPNST has a variety of histologic subtypes such as classic MPNST and epithelioid malignant peripheral nerve sheath tumors (EMPNSTs). Due to the diversity of histologic types, these tumors have a high histologic similarity to other benign and malignant soft tissue tumors. Due to the lack of specific diagnostic criteria, pathologic diagnosis is extremely difficult, since these tumors should be differentiated from other sarcomas according to the site of tumor occurrence and morphologic characteristics, which can be determined using immunohistochemical staining. The specific pathogenesis of MPNST is not well understood. Studies have shown that approximately 50% of MPNSTs are closely related to neurofibromatosis I (NF1), while other causes of these tumors include radiotherapy. Herein, we report the first case of a mixed tumor composed of classic MPNST and EMPNST elements in the inguinal region.

Ewing sarcoma with myxoid stroma: Case report of an unusual histological variant

We describe the case of a Ewing sarcoma with prominent myxoid stroma of the temporal bone in a 26-year-old female. Histologically, the tumor exhibited a fascicular growth pattern of round to spindled cells with a minimal amount of pale eosinophilic to clear cytoplasm and oval or spindled nuclei with finely dispersed chromatin and small nucleoli. Myxoid changes were prominent (>50%), with reticular or pseudoacinar growth of the loosely cohesive cells. The tumor showed strong expression of CD99, FLI1, and CD56 and was positive for the EWSR1-FLI1 fusion transcript. The diagnosis of Ewing sarcoma with myxoid stroma (myxoid variant) is particularly problematic owing to the large number of potential mimics. The tumor extends the morphologic spectrum of Ewing sarcoma beyond the previously described histological variants, and broadens the differential diagnosis. For any round/spindle cell sarcoma, prominent myxoid stroma and CD99 immunoreactivity should prompt consideration for molecular studies that include analysis of both EWSR1 and FLI1.

Tongue Schwannoma: A Clinicopathologic Study of 19 Cases

Schwannomas commonly occur in the head and neck but infrequently involve the oral cavity and rarely affect the tongue. The clinical and pathologic features of 19 cases of schwannoma arising in the tongue were analyzed. There were 13 males and 6 females ranging in age from 12 to 82 years (mean 34 years; median 29 years). The majority of tumors presented as an asymptomatic mass localized to the anterior two-thirds of the tongue. Histologically, 18 schwannomas exhibited characteristic Antoni A and B areas with the former pattern predominating. One tumor was composed exclusively of cellular Antoni A tissue and was classified as a cellular schwannoma. Tumor encapsulation was variable with nearly half of the lesions lacking a well-defined fibrous capsule. All were strongly and diffusely positive for S-100 protein. No recurrences were observed on clinical follow-up. Schwannoma of the tongue, although rare, should be separated from other types of lingual nerve sheath proliferations and tumors.

Intracranial synovial sarcoma: A clinical, radiological and pathological study of 16 cases

INTRODUCTION

Synovial sarcoma (SS) is a tumor of unknown origin and is extremely rare in the central nervous system. Most studies on intracranial SS included only one or two cases. To better understand the disease, we review a series of primary intracranial SS.

METHOD AND MATERIALS

16 primary intracranial SS in Tiantan Hospital during 2008-2017 were included. The clinical characteristics, including radiological and histological examination, operative records, and prognoses were reviewed.

RESULT

The case series included nine male and seven female patients with an average age of 23.8 years. Radiological results showed that the supratentorial region (81.25%) was the most common site of the brain involved. All patients were misdiagnosed as non-SS tumors. Gross total resection (GTR) was achieved in 12 cases (75.0%), and subtotal resection (STR) was achieved in 4 cases. All cases showed the characteristic SYT-SSX fusion gene, as detected by RT-PCR. The mean progression-free survival time (PFS) was 10.0 months and the mean overall survival time (OS) was 15.5 months. Multivariate analysis revealed that GTR and postoperative adjuvant radiotherapy were independent factors for PFS (HR = 6.143, 95% CI = 1.491-25.312; P = 0.012, HR = 6.143, 95% CI = 1.491-25.312; P = 0.012 respectively) and OS (HR = 9.000, 95% CI = 1.627-49.773; P = 0.012, HR = 0.017, 95% CI = 0.001-0.213; P = 0.002 respectively).

CONCLUSION

Intracranial SS were more frequently observed in the supratentorial region and in young patients without sex predilection. We recommend adjuvant radiation regardless of the extent of resection. More patients and longer follow-up periods were needed to further elucidate the biological features of intracranial SS.

Arm malignant peripheral nerve sheath tumour: a rare clinical presentation

Soft tissue sarcomas account for about 1% of malignant tumours. More than 50 subtypes of these tumours have been described with some being extremely rare, namely malignant peripheral nerve sheath tumours (MPNST). The authors present a case of a man aged 81 years with a medical history of an adenocarcinoma of the rectum, which was referred to our clinic due to a growing painless mass on the right arm. An MRI showed a well-delimited encapsulated mass involving the long head of the biceps muscle. Biopsy findings revealed a spindle cell tumour with cytonuclear pleomorphism. The patient underwent wide tumour excision and was successfully reconstructed with a latissimus dorsi functional muscle transfer. The presence of two pulmonary nodules on CT scan staging implied a lung biopsy that showed rectum primary tumour metastases. With these additional findings, the pathology department reassessed the case and reclassified the arm tumour as an MPNST, synchronous with pulmonary adenocarcinoma metastases of the rectum.

H3K27 trimethylation loss in malignant peripheral nerve sheath tumor: a systematic review and meta-analysis with diagnostic implications

BACKGROUND

Multiple studies have reported the loss of trimethylation at lysine (K) 27 on histone 3 (H3K27me3) in high-grade malignant peripheral nerve sheath tumors (MPNSTs). However, the diagnostic potential of this finding in MPNSTs remains yet to be fully substantiated. Correspondingly, our aim was to pool systematically-identified metadata in the literature and substantiate the incidence of H3K27me3 loss in this setting.

METHODS

Searches of 7 electronic databases from inception to May 2019 were conducted following PRISMA guidelines. Articles were screened against pre-specified criteria. The incidence of loss was then pooled by random-effects meta-analysis of proportions.

RESULTS

Nine pertinent studies described a total of 823 high-grade MPNST samples. When pooled, incidence (sensitivity) of complete H3K27me3 loss was estimated to be 53% (95% CI 42-64%). For MPNST subtypes, estimated incidences of complete loss in NF1 subtype was 52% (95% CI 41-62), in sporadic subtype was 53% (95% CI 36-70%), in the epithelioid subtype was 0% (95% CI 0-7%), and radiation-associated subtype was 98% (95% CI 86-100%). Finally, incidence of incomplete loss (specificity) in 1231 MPNST-mimic samples was estimated to be 96% (95% CI 90-99%). Certainty of these outcomes ranged from very low to high.

CONCLUSIONS

The incidence of complete H3K27me3 loss is substantial in high-grade MPNSTs and is low in MPNST-mimics. Greater cohort study and biological investigation will validate the certainty of these findings as well as elucidate their true molecular and clinical significances.

H3K27 trimethylation loss in malignant peripheral nerve sheath tumor: a systematic review and meta-analysis with diagnostic implications

BACKGROUND

Multiple studies have reported the loss of trimethylation at lysine (K) 27 on histone 3 (H3K27me3) in high-grade malignant peripheral nerve sheath tumors (MPNSTs). However, the diagnostic potential of this finding in MPNSTs remains yet to be fully substantiated. Correspondingly, our aim was to pool systematically-identified metadata in the literature and substantiate the incidence of H3K27me3 loss in this setting.

METHODS

Searches of 7 electronic databases from inception to May 2019 were conducted following PRISMA guidelines. Articles were screened against pre-specified criteria. The incidence of loss was then pooled by random-effects meta-analysis of proportions.

RESULTS

Nine pertinent studies described a total of 823 high-grade MPNST samples. When pooled, incidence (sensitivity) of complete H3K27me3 loss was estimated to be 53% (95% CI 42-64%). For MPNST subtypes, estimated incidences of complete loss in NF1 subtype was 52% (95% CI 41-62), in sporadic subtype was 53% (95% CI 36-70%), in the epithelioid subtype was 0% (95% CI 0-7%), and radiation-associated subtype was 98% (95% CI 86-100%). Finally, incidence of incomplete loss (specificity) in 1231 MPNST-mimic samples was estimated to be 96% (95% CI 90-99%). Certainty of these outcomes ranged from very low to high.

CONCLUSIONS

The incidence of complete H3K27me3 loss is substantial in high-grade MPNSTs and is low in MPNST-mimics. Greater cohort study and biological investigation will validate the certainty of these findings as well as elucidate their true molecular and clinical significances.

High expression of EZH2 as a marker for the differential diagnosis of malignant and benign myogenic tumors

Overlap in morphologic features between malignant and benign myogenic tumors, such as leiomyosarcoma (LMS) vs. leiomyoma as well as rhabdomyosarcoma (RMS) vs. rhabdomyoma, often makes differential diagnosis difficult and challenging. Here the expressions of Enhancer of Zeste Homolog 2 (EZH2), Suppressor of Zeste 12 (SUZ12), retinoblastoma protein associated protein 46 (RbAp46), Embryonic Ectoderm Development (EED) and ki-67 protein were detected by immunohistochemistry to evaluate their values in differential diagnosis. The expression of EZH2 mRNA was investigated by analyzing the Gene Expression Omnibus Datasets. The results demonstrated that EZH2 protein was detected in 81.25% (26/32) of LMS and 70.58% (36/51) of RMS, whereas none of leiomyoma (n = 16), rhabdomyoma (n = 15) and normal tissues (n = 31) showed positive immunostaining (p < 0.05). EZH2 protein was found to have a sensitivity of 91.30% and specificity of 100% in distinguishing well-differentiated LMS from cellular leiomyoma, and a sensitivity of 92.86% and specificity of 100% in distinguishing well-differentiated embryonal rhabdomyosarcoma (ERMS) from fetal rhabdomyoma. Besides, the expression of EZH2 mRNA was higher in LMS and RMS than in benign tumors (p < 0.05). The expressions of SUZ12 and RbAp46 protein were higher in RMS than in rhabdomyoma (p < 0.05). Conclusively, the high expression of EZH2 is a promising marker in distinguishing well–differentiated LMS from cellular leiomyoma, or well–differentiated ERMS from fetal rhabdomyoma, and the upregulation of EZH2 protein expression may occur at transcriptional level.