Malignant peripheral nerve sheath tumor: a comparison of grade, immunophenotype, and cell cycle/growth activation marker expression in sporadic and neurofibromatosis 1-related lesions

Prognostic significance of p14ARF, p15INK4b, and p16INK4a inactivation in malignant peripheral nerve sheath tumors

PURPOSE

p14(ARF), p15(INK4b), and p16(INK4a) are tumor suppressor genes that are located closely at 9p21 and are often coinactivated by genetic or epigenetic alterations. Malignant peripheral nerve sheath tumor (MPNST) is a rare sarcoma with poor prognosis. However, the prognostic implications of inactivation of p14(ARF), p15(INK4b), and p16(INK4a) in MPNSTs have not been adequately investigated. Here we carried out a genetic, epigenetic, and expression analysis of p14(ARF), p15(INK4b), and p16(INK4a), and clarified the prognostic significance of their inactivation in MPNSTs.

EXPERIMENTAL DESIGN

p14(ARF), p15(INK4b), and p16(INK4a) protein expressions were assessed by immunohistochemistry in 129 formalin-fixed samples of MPNST including 85 primary tumors. Thirty-nine samples, for which frozen material was available, were also investigated by Western blotting and quantitative reverse transcription PCR (RT-PCR) to detect p14(ARF), p15(INK4b), and p16(INK4a) protein and mRNA expression, and by multiplex real-time PCR, PCR single strand conformation polymorphism and methylation-specific PCR to detect p14(ARF), p15(INK4b), and p16(INK4a) gene alterations.

RESULTS

Immunohistochemically decreased expressions of p14(ARF), p15(INK4b), and p16(INK4a) were observed in 48%, 54%, and 49% of primary MPNSTs, respectively, and were significantly correlated with their concordant mRNA levels. As for gene alterations, homozygous deletion of CDKN2A was detected in one third of the cases. Inactivation of p14(ARF) and p16(INK4a) was associated with poor prognosis by both univariate and multivariate analyses. Furthermore, cases with inactivation of all p14(ARF), p15(INK4b), and p16(INK4a) genes showed the worst prognosis in a combined prognostic assessment.

CONCLUSION

A comprehensive analysis of p14(ARF), p15(INK4b), and p16(INK4a) inactivation status provides useful prognostic information in MPNSTs.

Malignant peripheral nerve sheath tumor of intracranial nerve: a case series review

OBJECTIVES

The incidence of malignant peripheral nerve sheath tumor (MPNST) is approximately 0.001%. Those involving intracranial nerves are even more exceptional. Little information is available concerning work up and management. Our objective is: (1) to review all cases of intracranial MPNST described in the literature, (2) to highlight the suspicion of intracranial MPNST, (3) to identify the gross pathology, the histopathology, the immunohistochemistry, (4) to discuss the differential diagnosis, the treatment, the recurrence rate, the follow-up, the incidence of metastasis and the prognosis.

METHODS

We reviewed English, Spanish and French literature published from 1950 to date. We used the following Keywords: "malignant peripheral nerve sheath tumor", "cranial nerve", "neurosarcoma", "malignant schwannoma", "neurofibroma", "malignant neurofibroma" and "nerve tumor". We considered cases where MPNST involved an intracranial cranial nerve. The results yielded 20 relevant studies, in which 31 patient's records were transcribed. We also added our case to this series.

RESULTS

We identified 32 cases of cranial MPNST including our case. The age ranged from 5 to 75 years old with most patients being in the 5th and 6th decade. Male to female ratio is 2.5:1. Most cases are developed sporadically (50%), 31% arise from a malignant transformation of schwannoma and 19% from a neurofibroma. Imaging findings were not specific. The cranial nerve VIII is the most involved (15/32), followed by the Vth (10/32) and the VIIth (5/32). 4 cases had neurofibromatosis type 1 and 2 had neurofibromatosis type 2. MPNST will strongly express protein S-100 and collagen IV-laminin. 13 cases were treated with radiotherapy for tumor recurrence and metastasis. In these cases the survival rate was better than the cases without radiotherapy. Fatal outcome occurred in 66% of patients whereas 19% were reported alive with or without complications. The seven cases reported to have metastasis were entirely to the spine. The mean time of recurrence or metastasis is 12.2 months.

CONCLUSION

MPNST of cranial nerves are very rare. In neurofibroma, even though MPNST is mainly associated to type 1, we should keep in mind its association to NF2. Mainstay of treatment is radical resection with adjuvant radiotherapy. Inaccessibility of cranial MPNST may explain the subtotal resection and thus the poor prognosis. Metastasis to the spinal cord is the most frequent one. A close postoperative follow-up is mandatory to eliminate recurrence.

Adult-type rhabdomyosarcoma: analysis of 57 cases with clinicopathologic description, identification of 3 morphologic patterns and prognosis

Adult-type rhabdomyosarcoma (RMS) has been classically defined as a pleomorphic sarcoma with desmin expression occurring in adult patients. To reevaluate this entity, we analyzed a series of 57 cases using immunohistochemistry for desmin, myogenin, alpha smooth muscle actin, h-caldesmon, pankeratin AE1/AE3, epithelial membrane antigen (EMA), S100 protein, CD34, MDM2, and CDK4. In this series, there were 36 men and 21 women aged from 22 to 87 years (median: 59). Tumors were mainly located in the lower limbs (27 cases), trunk wall (15 cases), and upper limbs (10 cases). Most tumors were deeply located (51/54) with a size from 1 to 30 cm (median: 8 cm). Cases were classified in 3 histologic categories: spindle cell RMS (25 cases), pleomorphic RMS (16 cases), and mixed type (16 cases). Forty-one tumors were grade 3 and 16 grade 2. Immunohistochemistry showed that every case was positive for desmin and myogenin. Alpha smooth muscle actin was positive in 21%, pankeratin AE1/AE3 in 20%, and CD34 in 13.2%. Treatment modalities and follow-up were available in 46 cases. Median follow-up was 60.9 months. Eight patients developed a local recurrence and 16 a distant metastasis with a 5-year overall survival rate of 52.6% and a 5-year metastasis-free survival of 62.9%. The only predictive factor for metastasis was histologic grade. In conclusion, adult-type RMS is a rare sarcoma occurring mainly in the extremities and trunk wall with 2 main histologic patterns, spindle cell, and pleomorphic patterns, which represent the end of the spectrum of a single entity.

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.

Malignant peripheral nerve sheath tumor in neurobifromatosis type-1: two case reports

Introduction

Malignant peripheral nerve sheath tumors are rare soft tissue sarcomas. They are considered to carry a poor prognosis with current therapeutic approaches. Successful treatment depends on a multimodal approach.

Case presentation

The authors report two cases with malignant peripheral nerve sheath tumors arising from pre-existing neurofibromas in the grounds of neurofibromatis-type I. Complete surgical removal of all lesions is considered before and after induction chemotherapy. Correlation of the response to chemotherapy in the context of the immuno-histopathological features of the tumors is also discussed with reference to the existing literature.

Conclusion

A need for a multidisciplinary approach with chemotherapy, surgery and radiotherapy is anticipated in the management of malignant peripheral nerve sheath tumors as described in these two reported cases. It is felt that further research on the molecular aspects of malignant peripheral nerve sheath tumors and neurofibromatis-type I will optimize treatment strategies in the future.

Atypical neurofibroma of the skin and subcutaneous tissue: clinicopathologic analysis of 11 cases

BACKGROUND

Neurofibroma (NF) is a relatively common cutaneous tumor, which typically presents little diagnostic difficulty. Occasionally, however, pleomorphic cells may be present in NF raising consideration of other neoplasms like malignant peripheral nerve sheath tumor (MPNST).

METHODS

This study examines the clinicopathologic and immunohistochemical features of 11 dermal and subcutaneous 'atypical' NF.

RESULTS

9/11 (82%) atypical NF were from females, aged 8-70 years. One patient had neurofibromatosis-1. Most presented on the extremities or trunk. The atypical cells had large hyperchromatic, irregular nuclei, and were arranged in a distinct lamellar or fibrillar pattern. Some tumors were hypercellular, but marked density characteristic of MPNST was not observed. All were nonplexiform. Mitoses were mostly absent. The pleomorphic cells expressed S-100 protein. All were negative for p53. MIB-1 was negative in 7/10 (70%) and stained only rare cells in 3 (30%). Epithelial membrane antigen (EMA) and p16 expression were variable. Of six patients with available follow-up, no tumor recurred and none developed malignancy (range 6-63, mean 33 months).

CONCLUSIONS

Superficial atypical NF, while morphologically unusual, has no apparent association with neurofibromatosis-1 or short-term risk of recurrence or malignant transformation. Awareness of this variant is important in order to avoid misdiagnosis of a more aggressive neoplasm.

Malignant peripheral nerve sheath tumors of cranial nerves and intracranial contents: a clinicopathologic study of 17 cases

Malignant peripheral nerve sheath tumors (MPNSTs) arising from cranial nerves or their branches are very uncommon. The literature consists mainly of isolated case reports and small series. We identified 17 such cases in 14 males and 3 females. With one exception, the tumors affected adults (age range 5 to 69 y, mean 39, median 32). Sites of involvement included vestibular nerves (n=6), vagal nerves (n=4), facial nerves (n=3) (1 centered in the geniculate ganglion), and 2 unspecified cranial nerves in the posterior fossa. In addition, 1 tumor involved the optic chiasm (n=1). Only 1 tumor arose in brain parenchyma of (frontal lobe). All but 3 lesions were intracranial. Five tumors arose in patients who satisfied clinical criteria for neurofibromatosis type 1 (NF1). One patient with a vestibular tumor and presumed NF2 had previously undergone resection of a contralateral vestibular cellular schwannoma. One posterior fossa tumor was a malignant melanotic schwannoma. Four patients had postirradiation malignant peripheral nerve sheath tumors, 2 having been treated for optic chiasm glioma, both being NF1 affected. One patient was irradiated for hypothalamic pilocytic astrocytoma and another for cervical Hodgkin disease. Identifiable precursor lesions included schwannoma (n=4), plexiform neurofibroma (n=2), and solitary intraneural neurofibroma (n=2). All tumors were histologically high grade (6 grade III and 10 grade IV). Three tumors showed heterologous elements, 2 osseous, and 1 rhabdomyoblastic. More often scattered than diffuse, S-100 protein staining was noted in 11 of 16 tumors and variable collagen IV staining in 10 of the 16. Immunoreactivity for p53 protein was diffuse and strong in 7 of 11 tumors. Twelve patients died within 17 months to 3 years of diagnosis, 1 was lost to follow-up, 2 are very recent cases, and 2 patients are currently alive, 1 after 2 recurrences, and another with spinal leptomeningeal metastases. Malignant cranial nerve sheath tumors are rare and are associated with the same poor prognosis as those of spinal nerves at other sites.

CD34-reactive tumors of the skin. An updated review of an ever-growing list of lesions

Over the past few years, a growing number of cutaneous tumors expressing CD34 is being reported. The list contains benign and malignant neoplasms as well as reactive and hamartomatous lesions of diverse lineages of differentiation, including fibroblastic, myofibroblastic, fibrohistiocytic, vascular, neural, adipocytic, smooth muscle, hematopoietic, melanocytic and epithelial. The more frequent diagnostic difficulties are found in spindle cell proliferations, mainly in those of the fibrocytic lineage. In part, this is because of the fact that in this area are, aside to well-defined entities, histologically and clinically diverse, recently reported cutaneous CD34-reactive lesions, whose definitions, limits and relationships are not completely established. The CD34 expression plays a key role in the differential diagnosis of some tumors, such as dermatofibrosarcoma protuberans, epithelioid sarcoma or pleomorphic hyalinizing angiectatic tumor of soft parts, with important therapeutic consequences. In others, as in desmoplastic trichilemmoma, it can help to resolve diagnostic problems in concrete cases. Finally, in many of the CD34-positive lesions, the diagnosis with the hematoxylin and eosin stain is straightforward. However, in all of them, the knowledge of the immunohistochemical profile contributes to our understanding of the cutaneous pathology.

Malignant peripheral nerve sheath tumors

Malignant peripheral nerve sheath tumors (MPNSTs) are a rare variety of soft tissue sarcoma of ectomesenchymal origin. MPNSTs arise from major or minor peripheral nerve branches or sheaths of peripheral nerve fibers and are derived from Schwann cells or pluripotent cells of neural crest origin. Arthur Purdy Stout played a pivotal role in the development of our current understanding of the pathogenesis of peripheral nerve sheath tumors by identifying the Schwann cell as the major contributor to the formation of benign and malignant neoplasms of the nerve sheath. Although this fact remains essentially true, the cell of origin of the MPNST remains elusive and has not yet conclusively been identified. Some have suggested these tumors may have multiple cell line origins. In the present review, MPNSTs and their epidemiology, diagnosis, management, and treatment are discussed.

Identification of p53 as a strong predictor of survival for patients with malignant peripheral nerve sheath tumors

The purpose of this study was to identify new prognostic biomarkers with clinical impact in malignant peripheral nerve sheath tumor (MPNST), a highly aggressive malignancy for which no consensus therapy exists besides surgery. We have used tissue microarrays (TMAs) to assess in situ expression of 14 cell-cycle-regulating proteins in 64 well-characterized MPNST patients: 36 sporadic and 28 with neurofibromatosis type 1 (NF1). We developed a new software application for evaluation and logistics of the TMA images and performed a literature survey of cell cycle proteins in MPNST. For NF1-associated patients, there was a clear association between nuclear expression of p53 and poor survival (p = 0.004). Among the other proteins analyzed, we also found significant associations between survival and clinical variables, but none were as strong as that for p53. For the total series of MPNSTs, p53 was shown to be an independent predictor of survival, and patients without remission, with tumor size larger than 8 cm, and with positive p53 expression had a 60 times greater risk of dying within the first 5 years compared with the remaining patients (p = 0.000002). This is the most comprehensive study of in situ protein expression in MPNST so far, and expressed p53 was found to be a strong surrogate marker for outcome. Patients in complete remission with a primary p53-positive MPNST diagnosis may be considered in a high-risk subgroup and candidates for adjuvant treatment.

Undifferentiated tumor: true identity by immunohistochemistry

CONTEXT

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

OBJECTIVE

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

DATA SOURCES

Review of the pertinent literature and the authors' experience.

CONCLUSIONS

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

Malignant triton tumor in a patient with Li-Fraumeni syndrome and a novel TP53 mutation

We report a 3-year-old boy with a malignant triton tumor (MTT) involving the left masticator space with local invasion and regional lymph node metastasis. Family history and detection of a novel germline TP53 mutation confirmed his diagnosis of Li Fraumeni syndrome (LFS). MTT has not been previously described in association with LFS. This case along with a comprehensive review of the literature, illustrate the importance of both somatic and germline TP53 mutations in the pathogenesis MTT. The tumor could not be resected and he was successfully treated with intensive induction chemotherapy, irradiation, and high-dose chemotherapy with autologous stem cell transplantation.

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

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

Nerve sheath tumor surgery: case-guided discussion of ambiguous findings, appropriateness of removal, repeated surgery, and nerve repairs

✓In this article the authors attempt to raise awareness of the pitfalls and controversial issues in nerve tumor surgery. In a case-guided format, examples of ambiguous findings, inappropriate tumor removal, repeated surgery, and nerve repairs are provided. The authors also discuss the need to establish a correct diagnosis preoperatively and to avoid the erroneous identification of malignant peripheral nerve sheath tumors (MPNSTs). They emphasize that not all of the principles of soft tissue sarcoma treatment protocols are applicable to MPNST. A situation of repeated surgery for supposedly malignant tumor is described, and an outline of the indications for, and an approach to, repair after lesion removal is given.

Malignant peripheral nerve sheath tumors

Malignant peripheral nerve sheath tumors (MPNSTs) are rare soft tissue sarcomas of ectomesenchymal origin. The World Health Organization coined the term MPNST to replace previous heterogeneous and often confusing terminology, such as “malignant schwannoma,” “malignant neurilemmoma,” “neurogenic sarcoma,” and “neurofibrosarcoma.” Malignant peripheral nerve sheath tumors arise from major or minor peripheral nerve branches or sheaths of peripheral nerve fibers, and are derived from Schwann cells or pluripotent cells of neural crest origin.

The Schwann cell is thought to be the major contributor to the formation of benign as well as malignant neoplasms of the nerve sheath. While this fact remains essentially true, the identity of cell of origin of the MPNST remains elusive, and has not yet been conclusively identified. It has been suggested that these tumors may have multiple cell line origins. In this review, the authors discuss the epidemiology, diagnosis, management, and treatment of MPNSTs.

Malignant peripheral nerve sheath tumor with rhabdomyosarcomatous differentiation (malignant triton tumor)

Malignant peripheral nerve sheath tumors arise from Schwann cells or within existing neurofibromas and have a strong association with type 1 neurofibromatosis. These tumors are histologically diverse and may contain malignant areas of divergent mesenchymal differentiation, the most common of which is skeletal muscle (rhabdomyosarcoma). Malignant peripheral nerve sheath tumor with rhabdomyosarcomatous differentiation is also known as malignant triton tumor. Malignant triton tumor has a worse prognosis than classic malignant peripheral nerve sheath tumor does, and the correct diagnosis requires attention to the clinical history and knowledge of the complexities regarding its differential diagnosis. In this review we discuss the clinical, histopathological, immunohistochemical, and prognostic features of this rare neoplasm.

Malignant peripheral nerve sheath tumors (MPNST)--clinicopathological study and treatment outcome of twenty-four cases

Background

Malignant peripheral nerve sheath tumor (MPNST) is biologically an aggressive tumor for which the treatment of choice is the surgery. We reviewed the clinical profile, diagnostic methods, treatment patterns, and outcome of twenty-four MPNST patients in this study.

Patients and methods

A retrospective analysis of 24 MPNST patients, treated from 1994 to 2002, in the department of Surgical Oncology at All India Institute of Medical Sciences, New Delhi, was done. A combination of gross, histopathological and immunohistochemical findings, and proliferation markers (MIB1) were considered for diagnosis and grade of the MPNST. Survival analysis was done by the Kaplan-Meier method and differences were evaluated with the log-rank test. Multivariate analysis was carried out by using Cox's proportional hazards model by using SPSS (Version 9, Chicago, Illinois) software.

Results

MPNST constituted 12% of all soft tissue sarcomas, where 21% (5/24) of patients had associated Von Recklinghausen's disease (VRHD). A higher incidence of male preponderance and multifocal MPNST were noted in the present series. At a mean follow-up of 38 months, 13 (54 %) patients had relapse of disease and 5-year over all and disease free survival were 58% and 35% respectively. In univariate analysis, sex (p = 0.05), tumor depth (p < 0.03), and cellular differentiation (p < 0.002) were shown to be adverse prognostic factors for disease free survival and sex (p = 0.04), cellular differentiation (p < 0.0004), and tumor grade (p = 0.05) for overall survival. However, in multivariate analysis, cellular differentiation (p < 0.005) and tumor grade (p < 0.01) emerged as independent prognostic factors for both disease free and overall survival, respectively. Postoperative radiotherapy (RT) has shown a definite role in both disease free and overall survival in this study.

Conclusion

MPNSTs constituted a significant proportion (12%) of soft tissue sarcoma in our medical center. Heterogeneous differentiation and multifocality of the tumor were few distinct features of MPNST. Sex and cellular differentiation were noticed as the new adverse prognostic factors and adjuvant radiotherapy has been proved to be a significant treatment tool in the current series.

Cluster analysis of immunohistochemical profiles in synovial sarcoma, malignant peripheral nerve sheath tumor, and Ewing sarcoma

As a result of overlapping morphologic and immunohistochemical features, it can be difficult to distinguish synovial sarcoma, malignant peripheral nerve sheath tumor, and Ewing sarcoma/primitive neuroectodermal tumor in core biopsies. To analyze and compare immunohistochemical profiles, we stained tissue microarrays of 23 synovial sarcomas, 23 malignant peripheral nerve sheath tumors, and 27 Ewing sarcomas with 22 antibodies potentially useful in the differential diagnosis, and analyzed the data with cluster analysis. Stain intensity was scored as none, weak, or strong. For CD99, tumors with membranous accentuation were independently categorized. Cluster analysis sorted five groups, with like tumors clustering together. Synovial sarcoma clustered into two groups: one cytokeratin and EMA positive (n = 11), the other mostly cytokeratin negative, EMA positive, bcl-2 positive and mostly CD56 positive (n = 9). Malignant peripheral nerve sheath tumor clustered into two groups: one S100 positive, with nestin and NGFR positivity in most (n = 10), the other mostly S100 negative, and variably but mostly weakly positive for nestin and NGFR (n = 11). Ewing sarcomas clustered into a single group driven by membranous CD99 staining. Thirteen cases failed to cluster (outliers), while three Ewing sarcomas clustered into groups of other tumor types. Paired antibodies for each tumor type determined by visual assessment of cluster analysis data and statistical calculations of specificity, sensitivity, and predictive values showed that EMA/CK7 for synovial sarcoma, nestin/S100 for malignant peripheral nerve sheath tumor, and membranous CD99/Fli-1 for Ewing sarcoma yielded high specificity and positive predictive values. Cluster analysis also highlighted aberrant staining reactions and diagnostic pitfalls in these tumors. Hierarchical cluster analysis is an effective method for analyzing high-volume immunohistochemical data.

Immunoprofiles in malignant peripheral nerve sheath tumor: three case reports and literature review

Because there are no standardized radiologic and histologic criteria, the differential diagnosis of malignant peripheral nerve sheath tumors (MPNSTs) from other spindle cell neoplasms poses great challenges for pathologists. Because early diagnosis of MPNSTs arising from benign peripheral nerve sheath tumors (BPNSTs) means a better prognosis, many immunohistochemical and molecular studies have recently emerged. Nevertheless, no gold standard diagnostic criterion is to be found in the literature. For example, S-100 protein is widely used in the diagnosis of MPNST. Other promising ancillary markers are p53 and Ki-67; however, the staining patterns and possible mechanisms of these markers are seldom mentioned in the literature. These evoke our interest. Only six cases diagnosed as MPNST were retrieved from the archives of the Department of Pathology, Kaohsiung Medical University Chung-Ho Memorial Hospital between 1988 and September 2005. Clinical files were available for three of them, and we found nuances in the immunohistochemistry from these previous reports. Here, we present these rare sarcomas and review the literature.

Aberrant expression of CHFR in malignant peripheral nerve sheath tumors

Mitotic checkpoint maintains genomic integrity before mitosis. Numerous observations have suggested that mitotic abnormalities produce chromosomal instability and aneuploidy. In MPNST, complex karyotypes showing numerical and structural aberrations have been described. 'Checkpoint with forkhead-associated domain and ring finger' (CHFR) was recently identified as defining a new early mitotic checkpoint. We examined the expression of CHFR in 96 cases of MPNST by immunohistochemical and molecular methods. We found reduced (score, < or = 3) expression of CHFR in 63 out of 96 (66%) cases of MPNST, and such alteration was significantly correlated with a high mitotic count, a high Ki-67-labeling index, and a poor prognosis. In addition, MPNST with normal karyotype showed a strong (score, =5) expression of CHFR. Our results support the assertion that CHFR functions as an inhibitor of tumor proliferation.

Expression patterns of cell cycle components in sporadic and neurofibromatosis type 1-related malignant peripheral nerve sheath tumors

The molecular biology underlying the development of highly malignant peripheral nerve sheath tumors (MPNSTs) remains mostly unknown. In the present study, the expression pattern of 10 selected cell cycle components is investigated in a series of 15 MPNSTs from patients with (n = 9) or without (n = 5) neurofibromatosis type 1 (NF1). Thirteen tumors did not express the cyclin-dependent kinase inhibitor, p16(INK4A), an observation that was related to homozygote gene deletions in three tumors, heterozygote deletions in five, and gross gene rearrangements in five. The absence of protein expression in the tumors with one seemingly intact allele was not caused by promoter hypermethylation of p16(INK4A) or p14(ARF). All tumor samples expressed normal sized RB1, cyclin D3, CDK2, CDK4, p21(CIP1), and p27(KlP1) proteins, and only a single tumor showed an aberrant protein band for one of these proteins, p21(CIP1). Cyclin D1 was absent in four tumors; all except one tumor showed expression of TP53 protein, and three of nine MPNSTs had expression of normal-sized MDM2. In conclusion, this study shows that the vast majority of MPNSTs had gross rearrangements of the p16(INK4A) gene, explaining the absence of the encoded protein in the same tumors. The level of expression was equally distributed between the familial (NF1) and sporadic cases, although it should be noted that the 2 cases with p16(INK4A) expression were sporadic. The data imply that the complete absence of p16(INK4A) is sufficient for activation of the cell cycle in most MPNSTs; thus, it is not necessary for tumor proliferation to further stimulate the cycle through alteration of other central components.

Niedrig-maligne periphere Nervenscheidentumoren der Nasen- und Nasennebenh�hlenschleimhaut

Sinonasal malignant peripheral nerve sheath tumors (MPNST) are infrequent neoplasms. 16 cases of low-malignant MPNST in this localization were retrieved from the files of soft tissue tumors established in Jena. They were examined with regard to their morphology and immunohistochemistry. The importance of an only partial immunostaining by S100 protein antibodies for diagnosis and differential diagnostic discrimination to benign peripheral nerve sheath tumors (schwannomas and neurofibromas) is explained. Finally, the differential diagnosis of spindle cell tumors in the sinonasal region in general is briefly discussed.

Cutaneous metastasis: a clinical, pathological, and immunohistochemical appraisal

BACKGROUND

Cutaneous tumor metastasis may be the first manifestation of cancer, but more often is a harbinger of advanced disease that portends an ominous prognosis. All skin accessions over the past 10 years from a large Veterans Administration (VA) hospital were reviewed.

METHODS

Archived histories, glass slides, and the immunohistochemical battery (IHC), were assessed to determine diagnostic accuracy.

RESULTS

Of the 100,453 cases reviewed, there were a total of 77 cases (75 males and 2 females) of cutaneous metastasis from the lungs (28.6%), metastatic melanoma (18.2%), gastrointestinal tract (14.2%), genitourinary tract (10.4%), head and neck (9.1%), hematologic (5.2%), breast (5.2%), and miscellaneous (<2%). Metastasis represented the first indication of an internal malignancy in 7.8% of cases. The cutaneous sites of involvement included the head and neck (28%), the trunk (40%), the extremities (18%), and multiple sites (14%). The age range was 38-83 years, with a mean of 62 years. The average time interval between diagnosis of internal malignancy and cutaneous presentation was 33 months (range: <1 month-22 years), and the average survival following diagnosis was 7.5 months (range: <1 month-8 years). In a cohort of subjects, a truncated immunohistochemical battery consisting of CK-7, CK-20, and S-100 was consistent with the expected staining pattern of the primary source of cutaneous metastasis in 83.33% of the patients.

CONCLUSIONS

Excluding the potential for age and gender bias in this study conducted in a VA setting, cutaneous metastases represent an uncommon, deadly, and late-developing occurrence in many patients. Compared with previous studies, lung carcinoma remains the most common of the cutaneous metastases, with a relative rise in the incidence of metastatic melanoma. The immunohistochemical battery of CK-7, CK-20, and S-100 is a helpful adjunct in narrowing the differential diagnosis of the primary site of a large proportion of cutaneous metastases, particularly tumors with an epithelioid appearance such as carcinomas and melanomas.

Pathologic classification of peripheral nerve tumors

Peripheral nerve tumors show an interesting histologic variety despite being composed ofa limited array of cellular constituents. As we learn more about the interplay between the Schwann cells, perineurial cells, and ganglion cells that comprise these tumors, it is likely that we will better understand the biologic behavior of these important tumors. Key issues for the pathologist include distinguishing schwannomas from neurofibromas, ganglioneuromas from neurofibromas involving ganglia, and MPNSTs from cellular schwannomas or neurofibromas. The association of each of these tumors with genetic tumor disorders provides a unique window into discovering basic mechanisms of cell regulation and tumorigenesis that may ultimately shed light on the biology of a much wider array of human disease.