Ewing sarcoma-primitive neuroectodermal tumor of the uterus: a clinicopathologic, immunohistochemical and ultrastructural study of one case.

INTRODUCTION: Ewing sarcoma-primitive neuroectodermal tumors (ES/PNET) constitute a family of neoplasms characterized by a continuum of neuroectodermal differentiation. ES/PNET of the uterus is rare. There are 43 cases published in the English literature as far as we know. We describe an additional case. CASE REPORT: A 56-year-old woman presented with a 2-month history of irregular menopausal vaginal bleeding. After surgical excision, microscopic, immunohistochemical and electron microscopic examination suggested the diagnosis of ES/PNET. The patient underwent combined chemotherapy consisting of ifosfamide, etoposide, and cisplatin. She was alive with no evidence of recurrence or metastasis after 41 months of the initial operation. DISCUSSION: In spite of the rarity of ES/PNET, we should consider it in the differential diagnosis of small cell neoplasms of the uterus.

Askin tumor with metastasis to the scalp: a histochemical, immunohistochemical and ultrastructural study.

A 29-year-old woman presented with facial edema, and imaging disclosed a tumor extending from the anterior chest wall to the anterosuperior aspect of the mediastinum. Transbronchial cytology of the primary tumor and biopsy of the metastatic scalp lesion were performed. Histologically, the tumor consisted of closely packed small round cells. The neoplastic cells generally had round nuclei, finely dispersed chromatin, and small to prominent nucleoli. Histochemically, the cytoplasm of the neoplastic cells contained abundant glycogen and stained with Grimelius silver. Immunohistochemically, the neoplastic cell membranes reacted with CD99 (MIC2) and the neoplastic nuclei reacted with Fli-1, but various other markers, including lymphocyte and skeletal muscle markers, were not detected. No neoplastic cells were also reactive for chromogranin A, synaptophysin, and neurofilament. Ultrastructurally, some neoplastic cells had delicate cytoplasmic processes and contained membrane-bound dense core granules in the cytoplasm. Even if results are immunohistochemically negative for neuroendocrine markers, the combination of immunohistochemistry of CD99 (MIC2) and Fil-1 may be useful in diagnosing Askin tumor or its metastatic lesion.

Olfactory neuroepithelioma: an immunohistochemical and ultrastructural study.

Three cases of olfactory neuroepithelioma are presented in this report. Histologically, these tumors were composed of small cells with round to oval, relatively hyperchromatic nuclei and scanty cytoplasm. The tumor cells were occasionally observed in tubular formations or rosette-like arrangements. Immunohistochemically, the tumor cells showed a positive reaction for cytokeratin AE1, cytokeratin CAM5.2, Ber-EP4, antisynaptophysin and anti-S100 protein in all cases. In two cases, LH-RH was detected in the tumor cells. Ultrastructurally, the tumor cells had the differentiation features of olfactory epithelium. Olfactory neuroepithelioma is a rare occurrence and it can be very difficult to distinguish olfactory neuroepithelioma from small cell carcinoma, neuroendocrine carcinoma and so-called "olfactory neuroblastoma" on the basis of hematoxylin and eosin stained sections alone. In controversial cases, a diagnosis of olfactory neuroepithelioma must be substantiated by ultrastructural and immunohistochemical findings, particularly regarding the detection of Ber-EP4 and LH-RH immunoreactivity.

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.

Primary Ewing's sarcoma of the suodenum: a case report.

We report a case of Ewing's sarcoma arising from the duodenum in a 20-year-old woman who presented with a rapidly progressive ulcerative lesion. The surgical specimen obtained via Whipple's operation revealed a small round-cell tumor (SRCT) in the first and second portion of the duodenum. The tumor cells revealed strong immunore-activity for CD 99 and vimentin and focal paranuclear dot-like immunoreactivity for cytokeratin. Electron microscopy showed primitive tumor cells with few cytoplasmic organelles, but neither neurosecretory granules nor specific cell junctions were present. On Western blot study, 68-kDa EWS/FLI1 fusion protein was detected. The occurrence of Ewing's sarcoma in the gastrointestinal hollow viscus has recently been recognized, and this case expands the known anatomic sites that can harbor Ewing's sarcoma by demonstrating primary duodenal involvement.

Peripheral primitive neuroectodermal tumor (PPNET) of pelvic origin: report of a case arising from an unusual location.

We report a rare case of a peripheral primitive neuroectodermal tumor (PPNET) originating from the left ileopsoas muscle in an adult patient with neoplastic thrombosis of the left external iliac vein, the common femoral vein and the left popliteal vein. We performed a median laparotomy with an oblique left inguinal incision to remove the neoplasm, which consisted of a large mass surrounding the iliac-psoas muscles, extending from the transverse apophysis of the spinal column to Scarpa's triangle, and passing through the lacuna musculorum. Histopathological examination revealed a primitive neuroectodermal tumor (PNET) with focal areas of necrosis, hemorrhage and vascular invasion. Immunophenotyping was positive for CD99, NSE, and focally for CK. Ultrastructural examination of the neoplastic cells showed often multiple nuclei with dense chromatin and very large nucleoli. The patient was discharged ten days after the operation. Adjuvant treatment consisted of radiotherapy at a dose of 2000 cGy in five fractions followed by six cycles of chemotherapy. The venous thrombosis was treated by anticoagulant therapy and recanalization of the occluded veins was obtained after two months of therapy. An MRI scan, carried out 12 months later, showed a local relapse, which was treated with chemotherapy and arterial chemoembolization.

Primitive neuroectodermal tumor (PNET) of the urinary bladder.

We report on the clinical, morphologic, immunohistochemical, ultrastructural, and molecular cytogenetic features of a primitive neuroectodermal tumor (PNET) primarily arising in the urinary bladder. An 81-year-old man presented with lymphedema of the lower extremities, fatigue, and urge incontinence. Radiographically, a tumor filling the entire cavity of the urinary bladder and extending into the pelvic and retroperitoneal tissue was noted. Histology of tumor biopsies showed a highly cellular, focally necrotic small round-cell tumor with numerous mitoses and occasional rosette-like structures. The tumor cells displayed significant immunoreactivity for neuron-specific enolase (NSE) and the MIC2 gene product (CD99). Dense-core granules were detectable by electron microscopy. A molecular cytogenetic analysis using comparative genomic hybridization (CGH) revealed gains of the chromosomes 3p, 6, 8q, 12, 17q, and 21q. The patient died two weeks after diagnosis. To the best of our knowledge, this is the fifth reported case of a PNET of the urinary bladder, and the first that includes a molecular cytogenetic analysis based on CGH.

Olfactory neuroepithelioma in a dog: an immunohistochemical and electron microscopic study.

A case of olfactory neuroepithelioma was investigated electron microscopically and immunohistochemically. The tumor mass was found in the nasal cavities of a 10-year-old female dog, which showed epistaxis, nasal discharge and facial swelling. The tumor tissue consisted of tubular structure of cuboidal to columnar cells and compactly arranged nests of small cells surrounded by a fibrovascular stroma. Mitotic figures were frequently observed. Immunohistochemically, the tumor cells frequently showed positive for neurofilament protein, synaptophysin and/or carnosine in addition to keratin. Ultrastructurally, tight junction was observed between the tumor cells. No dense-cored secretory granules were shown in the tumor cells. These findings indicated that the present tumor had neuronal and epithelial features probably originating from the olfactory epithelium.

Role of electron microscopy and other special techniques in the diagnosis of childhood round cell tumors.

A series of case presentations show unique challenges associated with childhood round cell tumors and the role of ancillary techniques in diagnosis. Electron microscopy is shown to be the most powerful individual technique. Immunohistochemistry is less effective but also essential. Other ancillary techniques may provide needed additional diagnostic information. Because this is an area where it is of great importance to secure the most rapid, accurate, and specific diagnosis possible, an integrated multimodal approach is recommended--incorporating light microscopic, electron microscopic, and immunohistochemical studies as a matter of routine, and providing for cytogenetic and/or molecular diagnostic studies as indicated.

Effects of all-trans retinoic acid and interferon alpha in peripheral neuroectodermal tumor cell cultures and xenografts.

Peripheral neuroectodermal tumors (PNET) have an unsatisfactory outcome when treated with standard approaches. Among novel treatments, the use of biological response modifiers has rarely been reported in this group of malignancies. We have previously demonstrated that both all-trans retinoic acid (ATRA) and interferon á (IFNá) can inhibit proliferation of human PNET cells and that ATRA can up-regulate IFNá receptor expression in vitro. In this study we evaluated the anti-tumor effects of ATRA and IFNá in PNET cells in vitro and in a human PNET xenograft model, using CHP100 cells. A synergistic inhibitory effect of ATRA and IFNá was observed on CHP100 cells in vitro. On the contrary, a significant inhibition of tumor growth was observed in mice treated with ATRA alone, whereas neither IFNá nor the combination of ATRA and IFNá, reached a statistically significant anti-tumor effect. Histologic examination of tumors revealed the presence of necrosis upon treatment with IFNá, whereas almost no necrosis, but a more differentiated morphology, confirmed by electron microscopy analysis, was associated with the ATRA containing treatments. Taken together these data show an in vitro and in vivo anti-tumor activity of ATRA in human PNET cells, although no synergism of ATRA and IFNá was observed in our xenograft model.

[Clinico-pathologic study of Ewing's sarcomas of bone and soft tissue and peripheral primitive neuroectodermal tumors].

OBJECTIVE: To study the diagnosis and differentiation of EW and PNET. METHODS: Fourteen cases of Ewing's sarcomas (EW) and peripheral primitive neuroectodermal tumors (PNET) were studied by light microscopy, immunohistochemistry and electron microscopy (EM). Twelve cases were followed up. Schmidt criterion was used for the differential diagnosis of EW and PNET. RESULTS: There were 6 cases of EW and 8 cases of PNET. Six of 8 PNET cases had Homer-Wright (H-W) rosettes. In this series, 12/14 cases were positive for O13 (HBA71) staining. NSE was positive in 3 cases of EW. All PNET cases were positive for neural markers, and 5 of them were positive for more than two of these markers. Electronmicroscopically, there were neurosecretory granules (4/4 cases), nerve-like protrusions and microfilaments (1/4 case) in PNET. In 3 of 6 EW and 1 of 6 PNET, PAS staining was positive. During the follow-up period from 2 months to 5 years, 3 cases with intraosseous EW remain alive and free of tumor. The remaining patients are dead or having their tumors metastasized. CONCLUSION: EW is more primitive in cell differentiation, while PNET has more neural differentiation. The presence of H-W rosettes is an important morphologic feature of PNET. To differentiate EW from PNET is of clinical significance O13 is a useful marker for the diagnosis of EW/PNET.

Intraoral tumor of Chievitz in a child.

Juxtaoral organs known as organs of Chievitz are intramuscular embryonic structures found close to the angle of the mandible near the insertion of the pterygomandibular raphae. They are considered of neuroepithelial origin with no known function. We describe the first tumor of the organ of Chievitz which presented intraorally in a child. Immunohistochemically, the Chievitz nests showed positive reaction for vimentin, cytokeratins, and epithelial membrane antigen and ultrastructurally demonstrated cytoplasmic processes and intermediate filament bundles. These observations, together with light microscopic features, suggest that the epithelial nests of the organ of Chievitz are meningothelial rather than neuroepithelial.

Clinicopathological characteristics of peripheral primitive neuroectodermal tumour of skin and subcutaneous tissue.

AIMS: To study the clinical and pathological features of primary malignant peripheral primitive neuroectodermal tumours (PNETs) of the skin and subcutaneous tissue, to discuss the differential diagnosis, and to review the existing literature on these tumours. METHODS AND RESULTS: Eight cases of PNETs presenting in the skin and subcutaneous tissue were identified from the pathology records of the Christie Hospital, Manchester. Detailed immunohistochemical studies were performed on all cases and seven tumours were subjected to electron microscopic examination. Detailed clinical and follow-up information was obtained on seven cases. Six tumours occurred in children and adolescents and two were seen in young adults (age range, 8-36 years). No sex or site predilection was observed. Five tumours occupied the dermis and subcutis and three were entirely located in the subcutaneous tissue. Microscopically, they were composed of small round cells and seven tumours contained glycogen. Only one tumour focally exhibited Home-Wright rosettes and neuropil. Two tumours contained rhabdoid or plasmacytoid cells in places and all cases showed microcystic and pseudovascular spaces. Immunostains revealed MIC2 (8/8), NSE (7/8), PGP9.5 (7/8), beta 2 microglobulin (7/8), neurofilament protein (6/8), S100 protein (3/8), synaptophysin (2/8) and Leu-7 (1/8) positivity. Anomalous cytokeratin (4/8), desmin (2/8), myoglobin (2/8), NKIC3 (4/8) and GFAP (1/8) staining was also noted. Ultrastructurally, neuroendocrine granules were detected in five cases and one case exhibited microtubules in processes. Adequate follow-up information was available in four cases. One patient died of metastatic disease. One child developed axillary lymph node metastasis but is alive with no evidence of disease 96 months after treatment. Two other patients are alive with no residual or recurrent disease 44 and 52 months after excision and radio/chemotherapy. CONCLUSION: PNETs are rare malignant small round cell tumours of the skin and subcutaneous tissue which are probably underdiagnosed. A correct diagnosis can be made on light microscopic features, demonstration of neuroendocrine granules on electron microscopy and a combination of MIC2, beta 2 microglobulin, and more than one neural marker positivity. These neoplasms should be differentiated from other cutaneous neoplasms composed of small round cells. The number of cases of cutaneous PNETs studied so far is rather small, and no firm conclusion can be drawn about their behaviour but long-term survival is possible in some cases.

Cell scattering of SK-N-MC neuroepithelioma cells in response to Ret and FGF receptor tyrosine kinase activation is correlated with sustained ERK2 activation.

The c-ret proto-oncogene encodes a receptor tyrosine kinase which plays an important role in kidney and enteric nervous system development. Germline mutations in c-ret are responsible for the dominantly inherited cancer syndromes, multiple endocrine neoplasia types 2A and 2B and familial medullary thyroid carcinoma as well as the developmental disorder Hirschsprung's disease. Using SK-N-MC neuroepithelioma cells stably transfected with an EGFR/Ret chimeric receptor, we have studied cellular consequences and signalling events following activation of exogenous EGFR/Ret and endogenous FGF and PDGF receptor tyrosine kinases in cells of neuroectodermal origin. Here we report that Ret activation led to cell scattering, growth inhibition and loss of anchorage-independent growth. Basic FGF, but not PDGF, evoked similar responses in those cells. Nevertheless, activation of all three receptor tyrosine kinases led to ERK2 activation. Analysis of the kinetics of ERK2 activation and downstream events revealed that Ret and FGF receptor activation led to sustained ERK2 activation and SRE transactivation, while PDGF treatment led to transient ERK2 activation and failed to induce SRE transactivation. Our results suggest that sustained, but not transient ERK2 activation may be involved in cell scattering.

Appraisal of the comparative utility of immunohistochemistry and electron microscopy in the diagnosis of childhood round cell tumors.

To provide an objective assessment of the comparative utility of fluorescence- and peroxidase-based immunohistochemistry and electron microscopy, an observer blinded study was conducted under realistic study conditions utilizing a large sampling of poorly differentiated pediatric round cell tumors. Working independently, using a single ancillary technique of particular expertise, each of three investigators attempted to render a specific diagnosis with regard to 50 diagnostically challenging tumors. The results were compared against the subsequent "file diagnosis" established by consensus with all relevant information made available. A grading scheme was applied wherein points were awarded based on the accuracy and confidence of diagnosis. A comparative efficiency rating, expressed as a percentage, was formulated by dividing the number of points awarded each technique by the total number of points theoretically available. Electron microscopy proved superior overall, with an efficiency rating of 89%. Immunoperoxidase and immunofluorescence studies yielded efficiency ratings of 71 and 61%, respectively. Used in combination, the techniques achieved an efficiency rating of 95%. Application of these ancillary techniques resulted in a revision of the provisional diagnosis in 11 of 50 cases, and left only two cases without a firm specific diagnosis.

Differentiating small round cell sarcomas of the soft parts by an innovative immunogold labeling method: an ultrastructural study.

A new immunoelectron microscopy procedure was developed by remaking the fixed-frozen tissue specimens into LR White resin blocks suitable for postembedding colloidal gold immunolabeling, and used to examine 16 cases of small round cell soft tissue sarcomas. In rhabdomyosarcoma, ultrastructural double-immunogold staining demonstrated a coexpression of muscle specific actin and desmin in the same tumor cell. In both Ewing's sarcoma and peripheral neuroepithelioma, the heterogeneous expression of MIC2 gene product (p30/32MIC2) in each tumor cell was demonstrated as well. In peripheral neuroepithelioma, the colloidal gold immunolabeling for neurofilament demonstrated the intermediate filaments surrounding microtubules. The procedure for ultrastructural colloidal gold immunolabeling using fixed-frozen tissue is thus considered to be useful not only for tumor diagnosis, but also for investigating various subcellular structures.

Peripheral neuroepithelioma (peripheral primitive neuroectodermal tumor) of the uterine cervix.

We report here a case of peripheral neuroepithelioma arising in the uterine cervix. A 44-year-old female had complained of irregular genital bleeding for several months and was diagnosed as extraosseous Ewing's sarcoma (EOE) from biopsy specimens initially. The tumor cells, which were intensely stained by periodic acid-Schiff (PAS) and digested with diastase, were uniformly small and round, had hyperchromatic nuclei and scant, indistinct cytoplasm. The surgically-removed tumor cells were immunohistochemically stained with antisera against neuro-specific enolase (NSE), tyrosine hydroxylase. In ultrastructural study, neurosecretory granules were observed. Finally we diagnosed this case as peripheral neuroepithelioma (peripheral primitive neuroectodermal tumor, PNET).

[Dysembryoplastic neuroepithelial tumor]. / Dysembryoplasticus neuroepithelialis tumor.

The dysembryoplastic neuroepithelial tumor is a benign central nervous system neoplasm of children and young adults manifesting almost exclusively in complex partial seizures. The authors report the case of an 8-year-old boy presenting with characteristic clinical and radiologic features who subsequently underwent surgery. Light microscopic, immunohistochemical and ultrastructural traits of the tumor are described demonstrating pluripotential differentiation of tumor cells and architectural features suggesting a dysontogenic lesion. A brief literature review on the biology and histologic diagnosis of the dysembryoplastic neuroepithelial tumor is provided. Although this uncommon tumor accounts for only a minority of intracranial neoplasms, its pathogenetic role has to be considered in the differential diagnosis of temporal lobe epilepsies. This is the first report on this recently described, rare neoplastic condition in Hungary.

The establishment and characterization of a peripheral neuroepithelioma cell line in soft tissue of extremity.

BACKGROUND: The histogenetic and biologic features of peripheral neuroepithelioma (PN) are still a matter of controversy. More detailed analyses might be facilitated by permanent PN cell lines. However, there have been only a few reports on the establishment of a PN cell line. EXPERIMENTAL DESIGN: We established and characterized a PN cell line and further carried out experiments for potentiality of drug-induced neural differentiation. RESULTS: The cultured cells were spindle shaped with slender cytoplasmic processes. The histologic features of transplanted tumors in nude mice were essentially the same as those of the original tumor. Immunohistochemically, the neuroectodermal characteristics of the cell line were demonstrated by positive stain for neuron specific enolase, glial fibrillary acidic protein, S-100 protein, neurofilament, and beta 2-microglobulin. Ultrastructurally, microtubules and dense core granules were observed in the cultured cells. Northern blot analyses revealed that c-myc was overexpressed in the cell line, whereas N-myc was not. The cell line showed neural differentiation after treatment with cAMP elevating reagents and nerve growth factor (NGF). The synergistic effects of cAMP analog and NGF on the neurite outgrowth were also observed. Furthermore, a cAMP-dependent protein kinase (PKA) inhibitor strongly blocked the action of cAMP analog, although it was not able to inhibit the same action of NGF. These findings suggested that the neurite outgrowth induced by the cAMP analog requires activation of PKA, whereas the same actions of NGF do not mediate such a pathway involving PKA activation. CONCLUSIONS: This is, to our knowledge, the first NGF responsive cell line derived from PN. This cell line might be valuable for further investigations of signal transduction pathways induced by cAMP analogs and NGF, for more precise analyses of the biological characteristics of PN, and finally, for the identification of differences between PN and several related tumors.

[Embryonal neuroepithelial tumors of the cerebral hemispheres]. / Embrional'nye neiroépitelial'nye opukholi bol'shikh polusharii golovnogo mozga.

33 embryonal neuroepithelial tumours of the cerebral hemispheres were examined light- and electron-microscopically, immunohistochemically. 4 types of tumours were distinguished: neuroblastoma, neuroepithelioma, ependymoblastoma and choroid carcinoma. Each type was characterised by its own pathohistological, immunohistochemical and ultrastructural features. Our results and literature data prove immunophenotypic and ultrastructural heterogeneity of embryonal neuroepithelial tumors of the cerebral hemispheres, in spite of some similarities in their pathohistological features.