On the histogenesis of Ewing's sarcoma. An ultrastructural, immunohistochemical, and cytochemical study

Inhibition of the oncogenic fusion protein EWS-FLI1 causes G2-M cell cycle arrest and enhanced vincristine sensitivity in Ewing's sarcoma

Ewing's sarcoma (ES) is a rare and highly malignant cancer that grows in the bones or surrounding tissues mostly affecting adolescents and young adults. A chimeric fusion between the RNA binding protein EWS and the ETS family transcription factor FLI1 (EWS-FLI1), which is generated from a chromosomal translocation, is implicated in driving most ES cases by modulation of transcription and alternative splicing. The small-molecule YK-4-279 inhibits EWS-FLI1 function and induces apoptosis in ES cells. We aimed to identify both the underlying mechanism of the drug and potential combination therapies that might enhance its antitumor activity. We tested 69 anticancer drugs in combination with YK-4-279 and found that vinca alkaloids exhibited synergy with YK-4-279 in five ES cell lines. The combination of YK-4-279 and vincristine reduced tumor burden and increased survival in mice bearing ES xenografts. We determined that independent drug-induced events converged to cause this synergistic therapeutic effect. YK-4-279 rapidly induced G₂-M arrest, increased the abundance of cyclin B1, and decreased EWS-FLI1-mediated generation of microtubule-associated proteins, which rendered cells more susceptible to microtubule depolymerization by vincristine. YK-4-279 reduced the expression of the EWS-FLI1 target gene encoding the ubiquitin ligase UBE2C, which, in part, contributed to the increase in cyclin B1. YK-4-279 also increased the abundance of proapoptotic isoforms of MCL1 and BCL2, presumably through inhibition of alternative splicing by EWS-FLI1, thus promoting cell death in response to vincristine. Thus, a combination of vincristine and YK-4-279 might be therapeutically effective in ES patients.

Multimodality Treatment in Ewing's Sarcoma Family Tumors of the Maxilla and Maxillary Sinus: Review of the Literature

The Ewing sarcoma family of tumors (ESFT) encompasses a group of highly aggressive, morphologically similar, malignant neoplasms sharing a common spontaneous genetic translocation that affect mostly children and young adults. These predominantly characteristic, small round-cell tumors include Ewing's sarcoma of the bone and soft tissue, as well as primitive neuroectodermal tumors (PNETs) involving the bone, soft tissue, and thoracopulmonary region (Askin's tumor). Extraosseous ESFTs are extremely rare, especially in the head and neck region, where literature to date consists of sporadic case reports and very small series. We hereby present a review of the literature published on ESFTs reported in the maxilla and maxillary sinus region from 1968 to 2016.

Proteomic comparison of the EWS-FLI1 expressing cells EF with NIH-3T3 and actin remodeling effect of (R/W)9 cell-penetrating peptide

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Comparison of tumoral EF versus non-tumoral 3T3 fibroblasts (SILAC).

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Characterization of EWS-FLI1 fusion protein impact on protein expression levels.

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Down-regulation of actin binding proteins responsible for passive dissemination.

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Investigation of (R/W)₉ cell-penetrating peptide actin remodeling activity.

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First proteomics study using a cell-penetrating peptide (R/W)_9.

EWS-FLI1 expression in NIH-3T3 fibroblasts has a profound impact on the phenotype, resulting in the cytoskeleton and adhesive capacity disorganization (EF cells). Besides this, (R/W)₉, a cell-penetrating peptide (CPP), has an intrinsic actin remodeling activity in EF cells. To evaluate the impact of the oncogenic protein EWS-FLI1 on proteins expression levels, a quantitative comparison of tumoral EF and non-tumoral 3T3 proteomes was performed. Then to see if we could link the EWS-FLI1 oncogenic transformation to the phenotype reversion induced by (R/W)₉, (R/W)₉ influence on EF cells proteome was assessed. To our knowledge no such ⿿CPPomic⿿ study has been performed before.

Biological significance

Up to now very few global quantitative proteomic studies have been published to help understand the oncogenic transformation induced by EWS-FLI1 fusion protein and leading to Ewing sarcoma development and dissemination. The comparison we did in this study between a model tumoral cell line EF and its non-tumoral counterpart (3T3) allowed us to highlight several features either common to most tumor types or specific to Ewing sarcoma. Particularly, lack of actin cytoskeleton organization could very likely be explained by the down-regulation of many important actin binding proteins. These results are in accordance with the hypothesis of a passive/stochastic mode of dissemination conferring Ewing sarcoma tumoral cell a high metastatic potential.

Spinal intradural metastasis from scapular Ewing sarcoma

Background

Ewing sarcoma is a primary bone neoplasm, which is a high grade aggressive small round blue cell tumour, and is currently recognized as a part of the Ewing family of tumours. It is the most lethal bone tumor, and is a rare malignant bone tumor accounting for 10% of all primary bone tumors, and 6% of malignant bone tumors. It has an average annual incidence of 3 per 1 million, found almost exclusively in Caucasians. It commonly occurs in long bones and pelvis but rarely involves the scapula. 85% of cases have metastasis within 2 years of diagnosis, rarely involving the meninges.

Case presentation

We report a case of a 25 year old Sinhalese Sri Lankan female, presenting with a 1 day history of bilateral lower limb weakness and urinary incontinence. She had a sensory level with flaccid paralysis of lower limbs and a painless bony lump in the left dorsal scapula. Investigations showed scapular primary Ewing sarcoma giving rise to spinal intradural metastasis. For the best of our knowledge this is the first reported case of a scapular Ewing sarcoma with spinal intradural metastasis presenting with lower limb paralysis.

Conclusion

Intradural spinal metastasis of Ewing sarcoma presenting with lower limb weakness, without a history of pain, though rarely, can be the first presentation, and can rapidly progress to brainstem involvement and death.

Dural metastasis of Ewing's sarcoma

BACKGROUND

Metastatic Ewing's sarcoma to the central nervous system is an uncommon condition and debate concerning the true origin of its metastases is still up to date. To the best of our knowledge, only two cases of dural metastatic Ewing's sarcoma have been published in the English medical literature. We present an additional case in a 24-year-old female and discuss the pathogenesis of these unusual tumors with review of the relevant literature concerning their treatment and outcome.

CASE DESCRIPTION

A 24-year-old female with previous history of pelvis Ewing's sarcoma and recently discovered lung metastases, presented with moderate headache for the past 2 weeks and weakness in her left leg for the past 2 days. Computed tomography scan and magnetic resonance imaging revealed an extra-axial right frontoparietal mass invading the superior sagittal sinus but with clear delineation with brain parenchyma. Imaging features were suggestive of a meningioma as no abnormalities in the skull abutting to the tumor were noted. The patient underwent surgical removal of her tumor. Near total resection was achieved and histological examination showed evidence of metastatic Ewing's sarcoma. Postoperative adjuvant radiation and chemotherapy were administered. The patient improved well postoperatively with full recovery of her motor weakness. She is symptom free with no signs of progression, at most recent follow-up, 8 months after surgery.

CONCLUSION

Despite its rarity, metastatic Ewing's sarcoma must be considered in the differential diagnosis of extra-axial dural masses particularly meningiomas.

Oxidative stress and therapeutic opportunities: focus on the Ewing's sarcoma family of tumors

Reactive oxygen species (ROS) are highly reactive by-products of energy production that can have detrimental as well as beneficial effects. Unchecked, high levels of ROS result in an imbalance of cellular redox state and oxidative stress. High levels of ROS have been detected in most cancers, where they promote tumor development and progression. Many anticancer agents work by further increasing cellular levels of ROS, to overcome the antioxidant detoxification capacity of the cancer cell and induce cell death. However, adaptation of the level of cellular antioxidants can lead to drug resistance. The challenge for the design of effective cancer therapeutics exploiting oxidative stress is to tip the cellular redox balance to induce ROS-dependent cell death but without increasing the antioxidant activity of the cancer cell or inducing toxicity in normal cells.

Is There a Predisposition Gene for Ewing's Sarcoma?

Ewing's sarcoma is a highly malignant tumor of children and young adults. The molecular mechanisms that underlie Ewing's Sarcoma development are beginning to be understood. For example, most cases of this disease harbor somatic chromosomal translocations that fuse the EWSR1 gene on chromosome 22 with members of the ETS family. While some cooperative genetic events have been identified, such as mutations in TP53 or deletions of the CDKN2A locus, these appear to be absent in the vast majority of cases. It is therefore uncertain whether EWS/ETS translocations are the only consistently present alteration in this tumor, or whether there are other recurrent abnormalities yet to be discovered. One method to discover such mutations is to identify familial cases of Ewing's sarcoma and to then map the susceptibility locus using traditional genetic mapping techniques. Although cases of sibling pairs with Ewing's sarcoma exist, familial cases of Ewing's sarcoma have not been reported. While Ewing's sarcoma has been reported as a 2nd malignancy after retinoblastoma, significant associations of Ewing's sarcoma with classic tumor susceptibility syndromes have not been identified. We will review the current evidence, or lack thereof, regarding the potential of a heritable condition predisposing to Ewing's sarcoma.

Electron Microscopy Renders the Diagnostic Capabilities of Cytopathology More Precise: An Approach to Everyday Practice

Cytology is a powerful diagnostic tool but to make definitive diagnoses, the use of ancillary techniques is imperative. By combining immunohistochemistry (IHC) and electron microscopy (EM), cytologic diagnoses can be as precise as those of surgical pathology. In the authors' daily practice of cytopathology they use all ancillary techniques available to them: histochemistry, IHC, EM, flow cytometry, and molecular pathology. IHC is frequently used as an ancillary technique in their daily practice but EM is many times their technique of choice. By the use of EM the authors can make specific final diagnoses, make the diagnosis more definitive, narrow the differential diagnosis, or determine the origin of a neoplasm with unknown primary site. Specimens obtained by fine-needle aspiration as well as all body fluids are suitable for EM. The limiting factor is to obtain the appropriate material with the diagnostic cells for ultrastructural examination. The common diagnostic dilemmas in the everyday practice of cytology are the following: mesothelioma vs. adenocarcinoma, neuroendocrine differentiation or not, the distinction of melanoma from adenocarcinoma and sarcoma, hepatocellular carcinoma vs. adenocarcinoma, and the origin of adenocarcinomas of unknown primary. The authors discuss how they approach these diagnostic problems in their everyday practice and how they incorporate EM in solving them.

Expression profiling of EWS/FLI identifies NKX2.2 as a critical target gene in Ewing's sarcoma

Our understanding of Ewing's sarcoma development mediated by the EWS/FLI fusion protein has been limited by a lack of knowledge regarding the tumor cell of origin. To circumvent this, we analyzed the function of EWS/FLI in Ewing's sarcoma itself. By combining retroviral-mediated RNA interference with reexpression studies, we show that ongoing EWS/FLI expression is required for the tumorigenic phenotype of Ewing's sarcoma. We used this system to define the full complement of EWS/FLI-regulated genes in Ewing's sarcoma. Functional analysis revealed that NKX2.2 is an EWS/FLI-regulated gene that is necessary for oncogenic transformation in this tumor. Thus, we developed a highly validated transcriptional profile for the EWS/FLI fusion protein and identified a critical target gene in Ewing's sarcoma development.

Keratin-positive Ewing's sarcoma: an ultrastructural study of 12 cases

Ewing's sarcoma/primitive neuroectodermal tumor (EWS/PNET) is an aggressive neoplasm of bone and soft tissue. Histologically, it is characterized by the presence of small round blue cells, which usually express MIC-2 and FLI-1 immunohistochemically. The most specific feature for diagnosis, however, is cytogenetic or molecular evidence of a consistent abnormality, the t(11;22)(q24;q12), or variants thereof. The immunohistochemical expression of keratins in a significant proportion of these cases has been highlighted in several recent studies. The ultrastructural features of these keratin-positive tumors have not, however, been characterized in detail. In this study we analyzed the ultrastructural features of 12 well-documented EWS/PNETs that stained strongly for pankeratin by immunohistochemistry. Ultrastructurally, the tumor cells contained a few organelles, which included a small number of mitochondria, poorly developed Golgi complexes, free ribosomes, and inconspicuous rough-endoplasmic reticulum. Rudimentary cell junctions were seen in 2 tumors while prominent junctions were observed in the remaining 10. Five tumors contained intracytoplasmic filaments, and definite tonofibrils were identified in 2. Well-developed basal lamina around tumor cells were also demonstrated in 2 tumors. Follow-up information was available for all cases. Seven patients died of disease, 2 are alive with disease, and 3 have no current evidence of disease. The cohort includes 5 patients with a type-1 translocation, which has been associated with a better prognosis in some studies; 4 of these patients have died of their disease, and 1 is alive with recurrent disease. This study shows that keratin-positive EWS/PNETs have evidence of epithelial differentiation ultrastructurally, and may possibly represent a more aggressive subset of the EWS/PNET group of tumors.

Primitive neuroectodermal tumor of the thumb metacarpal bone: a case report and literature review

A 27-year-old otherwise healthy patient was diagnosed with a primitive neuroectodermal tumor of the thumb metacarpal bone of the left hand. Based on a common chromosomal translocation this tumor shows a close relationship to Ewing's sarcoma. Its occurrence in the extremities is uncommon and involvement of the hand is extremely rare. The treatment consisted of neo- and adjuvant chemotherapy and marginal resection of the affected thumb metacarpal bone including periosseous soft tissue and reconstruction of the thumb by an intercalated segmental index pollicization.

Ewing's family of tumors involving structures related to the central nervous system: a review

This review consolidates information gleaned from several case reports and larger series on Ewing's sarcoma family of tumors (EFT) involving structures related to and found in the central nervous system (CNS). These tumors involve the skull, the spinal column, adjacent soft tissues, the meninges, and the brain. We have separated the cases by skull region and spinal column level, and we discuss the attendant differences in prognosis following treatment by neurosurgery, radiation, and chemotherapy. Light and electron microscopic features can be used to differentiate EFT from other small round blue cell tumors that involve the CNS (central primitive neuroectodermal tumor, lymphoma, etc.). Recent molecular and genetic findings in EFT provide new diagnostic methods. We conclude that EFT involving the CNS and adjacent structures is not so rare as previously stated and that the prognosis is more favorable, as a rule, than for the more common examples arising in the long bones and pelvis.

Neuroendocrine differentiation in Ewing's sarcomas and primitive neuroectodermal tumors revealed by reverse transcriptase-polymerase chain reaction of chromogranin mRNA

Ewing's sarcomas (ESs), primitive neuroectodermal tumors (PNETs), and neuroblastomas (NBs) are closely related neoplasms supposedly derived from the neural crest and belonging to the family of the small blue round cell tumors of infancy and childhood. We investigated the expression of the neuroendocrine and neuroectodermal markers chromogranin A (CgA) and secretogranin II (SgII) in ESs, PNETs, and NBs, both in primitive tumors (five, nine, and four cases, respectively) and in established cell lines (three ES and two PNET cell lines). Different technical approaches, namely immunohistochemistry, Northern blot analysis, and reverse transcriptase-polymerase chain reaction (RT-PCR) were used in parallel. Chromogranin A and secretogranin II production was constantly detectable in NBs by all procedures. CgA mRNA was detectable in most ESs and PNETs only by RT-PCR, whereas SgII mRNA was detectable in some ESs and PNETs by Northern blot analysis and in all tumors by RT-PCR. CgA and SgII proteins were never detectable by immunohistochemistry in ESs and PNETs. We conclude that neuroendocrine differentiation is shared by all three tumor entities, being more overt in NBs and rudimentary in ESs and PNETs; traces of chromogranin mRNA are detectable only by a highly sensitive RT-PCR procedure.

Ewing's sarcoma of humerus with epithelial differentiation

We report an unusual case of Ewing's sarcoma of the humerus with epithelial differentiation. This rare finding has recently been documented in this type of tumor.

An autopsy case of extraskeletal Ewing's sarcoma followed up for 24 years

A long-term (24 years) follow-up case of extraskeletal Ewing's sarcoma is reported. The light microscopic examination showed features hardly indistinguishable from Ewing's sarcoma of the bone, that is, the tumor cells were diffusely arranged and uniform in size and shape, and possessed glycogen in the cytoplasm. Homer-Wright rosettes were found only in the autopsy material. An immunohistochemical study using a neural marker (neuron-specific enolase) demonstrated positive staining in most tumor cells. An ultrastructural study revealed intracytoplasmic glycogen particles and incomplete neural characters as follows: the cytoplasmic processes resembled neural processes without neurosecretory granules, microtubules or neurofilaments. These findings suggest that this case finally acquired an incomplete neural character with repeated recurrence. This tumor was diagnosed extraskeletal Ewing's sarcoma, but in future it may be categorized as primitive neuroectodermal tumor (PNET).

FNA biopsy of small round cell tumors of childhood: cytomorphologic features and the role of ancillary studies

Pediatric tumors which are conventionally considered to be small round cell tumors (SRCTs) include the prototypical neuroblastoma as well as rhabdomyosarcoma (RMS), Ewing's sarcoma (ES), malignant lymphoma, and primitive neuroectodermal tumor (PNET). Other malignancies may be considered in the differential diagnosis such as small-cell osteogenic sarcoma, undifferentiated (anaplastic) hepatoblastoma, granulocytic sarcoma, blastemal type Wilms' tumor, and desmoplastic small-cell tumor of the peritoneum. The cytomorphologic features of conventional SRCTs is presented as well as the utility of ancillary studies performed on the aspirated material in making a specific and correct diagnosis. The role of the immediate cytologic assessment of the aspirate is stress, since this is a critical step in formulating an initial diagnostic impression that should prompt the need for additional material for pertinent ancillary studies. Although challenging, FNA cytology of SRCTs of childhood can be diagnostic in the majority of cases, allowing specific therapy to be given to patients with unresectable SRCTs without a tissue biopsy as well as documenting recurrent and/or metastatic disease.

Ewing sarcoma of bone in infants and toddlers. A clinicopathologic report from the Intergroup Ewing's Study

BACKGROUND

Nineteen patients with Ewing sarcoma of bone, each younger than 3 years of age at the time of initial presentation, are reported. These children represent an unusually young age group for documented Ewing sarcoma and represent 2.6% of all patients registered in the Intergroup Ewing's Sarcoma Study (IESS).

METHODS

The diagnosis was made on combined histologic, clinical, and radiographic grounds and was supported by immunohistochemistry in nine patients and electron microscopic study in eight patients. Immunohistochemical studies showed no staining against neuro-specific enolase, chromogranin, or S-100 in any patients, and in only one in nine patients were results of such studies focally positive against Leu-7.

RESULTS

The most marked clinical variation between this group of infants and the general IESS patient population was a striking predominance of female patients in the younger age group (P < 0.001). There was a trend toward more rib, pelvis, and proximal long bone tumors in the infants and toddlers. The overall survival rate of the infants was 56%, almost identical to the survival rates of the older children. All of the infants who died of disease did so within 4 years. Extended follow-up as long as 9.9 years has found no late deaths attributable to tumor. The most significant late complications of therapy included cardiotoxicity with cerebral embolization from the heart and a short lower limb secondary to radiation therapy.

CONCLUSIONS

Ewing sarcoma must be considered in the differential diagnosis of small cell, round cell, and blue cell tumors in bone, even in infants and toddlers.

The immunophenotype of Ewing's sarcoma. An immunohistochemical analysis

Since 1963, 53 cases of Ewing's sarcoma have been diagnosed at the N. Goormaghtigh Institute of Pathological Anatomy. All tumours were classified according to their growth pattern as described by Kissane: diffuse, lobular or organoid, the latter with pseudorosettes, or belonging to the fillagree type. In 45 cases, an immunohistochemical examination was carried out on routinely processed material in order to determine the immunophenotype of the tumours and to get more information on the histogenesis of the tumours. Antibodies against cytokeratin, desmin, vimentin, neurofilaments, neuron-specific enolase, Leu7, synaptophysin, chromogranin, the muscle-specific actin, the Von Willebrand factor and the common leucocyte antigen were used in a biotin-streptavidin procedure. The presence of neural markers such as neuron-specific enolase, synaptophysin and Leu7 was proved in the majority of the cases. The expression of the three markers was absent in only two cases. Neurofilaments were demonstrated to be present in 5 of the 6 cases for which fresh material was available. The results of this study point towards a possible neuroectodermal origin of Ewing's sarcoma. This is in agreement with the results of cell culture experiments and of cytogenetic studies.

Cytogenetic and pathologic aspects of Ewing's sarcoma and neuroectodermal tumors

Diagnostic classification of poorly differentiated, round cell, primitive neuroectodermal neoplasms, including Ewing's sarcoma, peripheral neuroepithelioma, Askin's tumor, and esthesioneuroblastoma, is challenging to the surgical pathologist using conventional histopathologic approaches because of very similar and overlapping morphologic and cytologic features. Furthermore, distinguishing these neoplasms from neuroblastoma, embryonal rhabdomyosarcoma, small cell osteogenic sarcoma, and non-Hodgkin's lymphoma can be difficult. This paper describes and reviews the cytogenetic and molecular genetic changes in these tumors and demonstrates how the ability to detect these changes has enabled a greater understanding of the histogenesis, classification, diagnosis, and prognosis of these neoplasms.

Type I and type II insulin-like growth factor receptors and their function in human Ewing's sarcoma cells

Binding studies using recombinant human 125I-labelled insulin-like growth factor I ([125I]IGF-I) revealed IGF-I receptors in three Ewing's sarcoma cell lines with Kd ranging from 74 x 10(-12) M to 100 x 10(-12) M and Bmax = 36-63 fmol/mg cell protein. [125I]IGF-I binding was displaced by IGF-I, IGF-II and insulin with IC50 values of 1.5 nM, 6.3 nM and 0.7 microM respectively. Recombinant human [125I]IGF-II radioligand-binding assays in the cell lines disclosed specific binding sites for IGF-II with Kd = (110-175) x 10(-12) M and Bmax varying from 21 fmol/mg to 72 fmol/mg cell protein. Neither IGF-I nor insulin displaced [125I]IGF-II binding. IGF-I was found to increase basal glucose transport by maximally 1.5 times with EC50 = 0.9 nM IGF-I. The efficacy and potency of IGF-II on glucose uptake were comparable to those of IGF-I whereas insulin was ineffective. IGF-I and IGF-II also provoked stimulation of glycogen synthesis in Ewing's sarcoma cells. The maximal glycogenic response was reached at 0.01 microM IGF-I and 0.1 microM IGF-II, the EC50 value being approximately 1 nM IGF-I and 2 nM IGF-II. Insulin did not significantly influence glycogen formation. IGF-I and IGF-II but not insulin increased DNA synthesis in Ewing's sarcoma cells. The maximal mitogenic response was obtained with 10 nM IGF-I or IGF-II with an EC50 value of about 0.7 nM for both peptides. alpha-IR-3, a monoclonal antibody specific for the IGF type I receptor, effectively blocked IGF-I- and IGF-II-mediated metabolic responses. In conclusion, the data show that IGF-I and IGF-II induce rapid and long-term biological responses in Ewing's sarcoma cells exclusively through interaction with IGF type I receptors.

Evidence for heterogeneous groups of neuronal differentiation of Ewing's sarcoma

We have investigated the capability of differentiation of Ewing's sarcoma (ES) towards a neuronal direction through the establishment of four extraosseous ES cell lines and by in vitro stimulation with dibutyryladenosine cyclic monophosphate (db-cAMP) of eight ES lines. All except one of the lines expressed the molecule defined by 5C11, the antibody specifically reactive with ES. Two ES lines expressed a 200 kilodalton (kD) neurofilament protein (NFP) although their original tumours were negative for NFP. Elongation of cytoplasmic processes and increased NFP expression were observed after db-cAMP treatment of these lines and microtubules in the cytoplasmic processes were ultrastructurally demonstrated. Six lines were NFP negative, but three lines changed their morphology after induction of 200 kD NFP expression by db-cAMP treatment. The other three showed no definitive differentiation after db-cAMP treatment. Chromosomal analysis of the new ES lines showed the typical t(11;22) in one line and a +der(22) in two lines. No correlation was observed between the chromosomal abnormality and the differentiation capability. We conclude that ES is a heterogeneous group of tumours with respect to capability of differentiation into the neuronal lineage, but it is clearly distinguished from peripheral primitive neuroectodermal tumours by its 5C11 reactivity.

Primary spinal epidural extraosseous Ewing's sarcoma

The case of a 7-year-old boy with a spinal epidural extraosseous Ewing's sarcoma (EES) is presented. He is in complete remission without neurologic deficit 40 months after diagnosis. Another 15 cases were found in the literature and are discussed together with this patient. Twelve of them were male patients. The mean age of the patients was 17.5 years (range, 4 to 47). Symptoms included back pain and/or radicular pain (100%), paresis of one or both legs (83%), sensory disturbances, and bladder and bowel dysfunction. The mean diagnostic delay was 5.8 months. Each patient underwent laminectomy; complete resection of the tumor was impossible in more than 50% of the cases. Most patients received radiation therapy and/or chemotherapy. Four patients suffered from local recurrence, eight from metastases. Ten (63%) patients died, 1 to 48 months (mean, 16) after diagnosis. The differential diagnosis is discussed, including disk herniation and several benign and malignant tumors.

Atypical primitive neuroectodermal tumors. Comparative light and electron microscopic and immunohistochemical studies on peripheral neuroepitheliomas and Ewing's sarcomas

Recently, primitive neuroectodermal tumors (PNETs) have been shown to cover a wide spectrum of small round cell sarcomas, probably including some Ewing's sarcomas (ESs) and extraskeletal Ewing's sarcomas (EESs), in addition to classical peripheral neuroepitheliomas (PNs). In studies of small cell sarcomas, we found a group of undifferentiated tumors resembling PNETs with some features of neuroectodermal differentiation, but possessing areas of relatively large, pleomorphic cells. To clarify the nature of these tumors and their relationship to PNETs, we examined the variety of histological, immunohistochemical and ultrastructural features of 11 small cell sarcomas. Five of these tumors were composed of uniform, small round cells and were classified as PNs because of the presence of definite Homer-Wright rosettes and fibrillary processes. The presence of well developed neurite-like processes containing neurosecretory granules and immunoreactivities for various neural markers suggested that these PNs showed more advanced neuronal differentiation. Two tumors, with the classical features of ES, showed no ultrastructural evidence of neuronal differentiation, although only gamma-gamma neuron-specific enolase (NSE) positivity was detected. Four undifferentiated tumors with atypical features, included in this study as an atypical PNET group, showed certain neuroectodermal characteristics, such as ganglion cell differentiation, perivascular pseudorosettes, and gamma-gamma NSE reactivity. It is concluded from this study that PNETs may include small round cell tumors showing different degrees of neuro-ectodermal differentiation and some histological variations.

MIC2 is a specific marker for Ewing's sarcoma and peripheral primitive neuroectodermal tumors. Evidence for a common histogenesis of Ewing's sarcoma and peripheral primitive neuroectodermal tumors from MIC2 expression and specific chromosome aberration

This study reports on the specific expression of the MIC2 gene, a pseudoautosomal gene located on the short arms of the X and Y chromosomes, on Ewing's sarcoma (ES) and peripheral primitive neuroectodermal tumor (pPNET) cells. The gene product, a cell membrane protein, is recognized by the newly established monoclonal antibody (MoAb) HBA-71 and the previously described MoAb 12E7 and RFB-1. Furthermore, the reaction pattern of the MIC2 antibodies, especially HBA-71, with normal tissues and a great number of benign and malignant tumors (70 different tumors, 199 tumor samples), as well as the correlation between the specific chromosomal aberrations, i.e., the t(11;22) and the del(22) and the expression of this antigen, are demonstrated. Both ES and pPNET cells express the MIC2 gene in very high amounts, which represents a highly selective and almost unique feature of these cells, making an assignment of these tumors in one entity even more likely. The MIC2 antibodies are of great value for clinical and research purposes.

Immunocytochemical and ultrastructural studies of the histogenesis of Ewing's sarcoma and putatively related tumors

The histogenesis of Ewing's sarcoma (EW) and extraskeletal Ewing's sarcoma (EEW) is still disputable. Their relationship to the so-called Askin's tumor, neuroectodermal tumor of bone, and peripheral neuroblastoma remains to be established. In an attempt to clarify these points, immunocytochemical and ultrastructural studies were done on tissues from 14 cases of EW, 4 cases of EEW, and 9 cases of primitive neuroectodermal tumor (PNET) and compared with neuroblastoma and olfactory neuroblastoma. Six tumors categorized initially as EW and EEW on biopsy, turned out to be PNET by extensive histologic and/or ultrastructural observations. Abundant glycogen was recognized not only in 16 of 18 cases of EW and EEW, but also in seven of nine cases of PNET. Fine fibrillar cell processes were seen between tumor cells, at least in limited areas even in cases of EW and EEW. Immunocytochemically, neuron-specific enolase (NSE), neuroblastoma cell surface antigen (NBCA), neuron cell surface antigen (NCSA), and neurofilament (NF) were demonstrated not only in neuroblastoma, but also frequently in cases of EW, EEW, and PNET. The results seem to suggest that EW and EEW represent the most immature forms of neuroectodermal tumor. Electron microscopic study showed predominantly primitive cells with occasional areas of cell processes, neurosecretory granules, and microtubules, suggesting a neuroectodermal origin.

Ewing's sarcoma of bone and soft tissues

Ewing's sarcoma is a distinctive clinical and pathologic entity that may be intraosseous or of soft-tissue origin. In the facial bones, the incidence of the sarcoma is estimated at 2.5% of all Ewing's sarcoma of bone. The soft tissue of the head and neck account for 11% of extraskeletal sites of the neoplasm. Combined modality treatment has modified its high-grade malignancy.

Ewing's sarcoma. A retrospective study of histological and immunohistochemical factors and their relation to prognosis

Histological and immunohistochemical features of 87 patients with conventionally diagnosed Ewing's sarcoma were studied retrospectively on routinely processed material and evaluated with regard to prognostic significance. 74% were convincingly positive when stained for vimentin, 13% were doubtful, and 13% were negative. A varying degree of positivity for neuron-specific enolase (NSE) was found in 15%; these cases all co-expressed vimentin. A single tumour contained scattered cytokeratin-positive cells. Positivity for the leukocyte common antigen (LCA) could be demonstrated in three cases; these were excluded from the statistical analysis of prognostic factors. Growth pattern, soft tissue invasion, monomorphic or dimorphic cell population, and PAS-, NSE- or vimentin-positivity did not influence survival significantly. However, prognosis was increasingly poor with increasing degree of necrosis: median survival was 28 months for grade I necrosis (less than 10%), 16 months for grade II (10-50%), and 11 months for grade III (greater than 50%), p less than 0.0005. A mitosis count of less than 1 per high-powerfield (HPF) was correlated to a median survival of 26 months, greater than or equal to 1 per HPF to 12 months, p less than 0.05. The findings indicate some degree of heterogeneity in Ewing's sarcoma which may be related to primitive peripheral neuroectodermal tumours (PNETs), or be a true blastoma. In future trials, diagnostic criteria (including immunohistochemistry) should be clearly defined and materials should be large enough to allow for stratification according to prognostic factors.

A case of Ewing's sarcoma diagnosed by fine needle aspiration. Light microscopy, electron microscopy and chromosomal analysis

A Ewing's sarcoma of the thigh in a 9-year-old boy was diagnosed by light microscopy, electron microscopy, and chromosomal analysis performed on fine needle aspirates.

Malignant round cell tumor of bone with neural differentiation (neuroectodermal tumor)

A malignant round cell tumor primary in bone is reported in a young girl, showing histologically rosette formation and pseudoalveolar spaces. Vimentin, NSE, and S-100 were positive. Electron microscopy demonstrated abundant glycogen and neural features such as cell processes, microtubules, and occasional dense-core granules. Whether this neuroectodermal tumor represents a separate entity or is a variant of Ewing's sarcoma should wait for further experience, in the light of recent evidence suggesting that Ewing's sarcoma arises from primitive multipotential cells.

Induction of glycogenolysis in cultured Ewing's sarcoma cells by dopamine and beta-adrenergic agonists

This study describes hormonal regulation of glycogen metabolism in Ewing's sarcoma cells. 3H-Glycogen synthesized in cultured Ewing's sarcoma WE-68 cells from 3H-glucose was hydrolyzed in a concentration-dependent manner by various catecholamines. The order of potency for the glycogenolytic effects of catecholamines was isoproterenol greater than or equal to dopamine greater than norepinephrine greater than epinephrine. The concentrations giving half-maximal effectiveness (EC50) were about 2 x 10(-8) M, 3 x 10(-8) M, 8 x 10(-8) M, and 5 x 10(-7) M for isoproterenol, dopamine, norepinephrine, and epinephrine, respectively. Higher concentrations of each of the catecholamines were necessary to elicit EC50 stimulation of cyclic AMP production in Ewing's sarcoma cells. Glycogenolysis induced by dopamine was blocked by chlorpromazine, a dopamine D1-receptor antagonist, but not by haloperidol, a dopamine D2-receptor antagonist. The glycogenolytic action of norepinephrine was markedly reduced by propranolol, a beta-adrenoreceptor antagonist, and was not affected by yohimbine, an alpha-adrenoreceptor antagonist. In addition, chlorpromazine also antagonized the glycogenolytic response to norepinephrine. Dibutyryl cyclic AMP, 3-isobutyl-1-methylxanthine, and the diterpene forskolin were also found to induce 3H-glycogen hydrolysis. Our data indicate that catecholamines exert their glycogenolytic effects in Ewing's sarcoma cells by stimulation of cyclic AMP formation via beta-adrenergic receptors and dopamine D1-receptors.

Extraskeletal Ewing's sarcoma of the scalp

A 15-year-old boy had an extraskeletal Ewing's sarcoma arising in the soft tissues of the scalp. The tumor was rapidly growing, subcutaneous mass unattached to the underlying bony structures. Histologic examination revealed a proliferation of primitive-appearing, round to oval cells adopting a lobular configuration. Immunohistochemical studies confirmed the undifferentiated mesenchymal nature of the neoplasm.

Rhabdomyosarcoma presenting with diffuse bone marrow involvement, hypercalcemia and renal failure

Rhabdomyosarcoma and other small round-cell neoplasms of infancy and childhood frequently involve the bone marrow. An unusual clinical presentation of diffuse bone marrow involvement as the sole manifestation of the disease represents a difficult diagnostic challenge. We report the case of an 18-year-old boy presenting with lower back pain, sternum tenderness, anemia, thrombocytopenia, leukoerythroblastic blood film, hypercalcemia, and renal failure. No solid tumor was found. A diagnosis of rhabdomyoblastic bone marrow metastatic involvement was initially suggested by the morphological picture, and later confirmed by the ultrastructural findings. Hypercalcemia and renal failure were controlled, initially, with furosemide and calcitonin. The patient was treated with intensive chemotherapy, including vincristine, actinomycin D, cyclophosphamide, and doxorubicin. A remission was achieved, lasting 5 months until relapse.

Primary Ewing's sarcoma involving the bones of the head and neck

Ewing's sarcoma is a rare tumor of the bone. In the Intergroup Ewing's Sarcoma Study (IESS) approximately 4% of the primary bone tumors arose in the bones of the head and neck. The mean age of patients was 10.9 years; boys slightly dominated the group. Signs and symptoms were local in distribution, with a mass or swelling most frequent. As in other sites, we categorized the dominant histologic pattern as diffuse or filigree, the latter carrying a more unfavorable prognosis. The radiographic appearance may be atypical as compared to Ewing's sarcoma at other sites. Prognosis of head and neck Ewing's is significantly better than Ewing's sarcoma overall. The gnathic bones were commonly affected, yet there was no associated mortality. No patient with primary disease in the bones of the head and neck who survived for 5 years on any of the IESS protocols has subsequently died.