Peripheral primitive neuroectodermal tumour and extra-osseous Ewing's sarcoma; a histological,immunohistochemical and DNA flow cytometric study

Although peripheral primitive neuroectodermal tumour (pPNET) and extra-osseous Ewing's sarcoma (EES) are thought to be closely related neoplasms, their clinical behaviour differs considerably. To determine the clinical relevance of the Schmidt classification scheme for differentiating pPNET and EES, 20 tumour specimens of poorly differentiated round cell tumours were evaluated. In addition, the diagnostic value of several neural markers and the prognostic value of quantitative morphological variables (DNA ploidy, S-phase fraction, and the mitotic activity) were assessed. Homer-Wright rosettes were present in 9 tumours. Neuron specific enolase (NSE) was expressed in 11 tumours, 8 of which expressed a second neural marker (CD57, S100, or neurofilament). According to the Schmidt classification, 11 pPNET and 5 EES were distinguished. HBA-71 was exclusively expressed in pPNET and EES. The remaining tumours were classified as sarcoma not otherwise specified (n=2), rhabdomyosarcoma (n=1), and desmoplastic tumour with divergent differentiation (n=1). EES611 patients fared significantly better than the pPNET patients (100% versus 42% 5-year survival). Neither DNA ploidy nor S-phase fraction assessed in 12 evaluative histograms (9 pPNET and 3 EES), nor mitotic activity yielded information of additional prognostic value. On the basis of this study and the Schmidt classification scheme, it can be concluded that if the diagnosis of EES and pPNET is based on light microscopy (Homer-Wright rosettes) and/or immunohistochemistry (at least two neural markers, i.e. NSE, S-100, CD57, and neurofilament), the classification provides important clinical information. Furthermore, positivity for HBA-71 is helpful in differentiating pPNET and EES from all other small round cell tumours.     

Peripheral primitive neuroectodermal tumor/Ewing's sarcoma of the craniospinal vault: case reports and review

The peripheral primitive neuroectodermal tumor/Ewing's sarcoma family tumor (pPNET/ESFT) group includes small round cell tumors of the bone, soft tissue, and nerve with morphological attributes of the germinal neuroepithelium. Peripheral PNETs/ESFTs also occur within the craniospinal vault, a region including the central nervous system, the meninges, and the cranial and spinal nerve roots. Gene rearrangements between the EWS gene on chromosome 22q12 and members of the ETS gene family are common in and specific to pPNETs/ESFTs. Another defining characteristic of pPNETs/ESFTs is their membranous expression of the MIC2 gene product. We describe 2 cases of pPNETs within the craniospinal vault. An intradural tumor arising from the nerve roots of the cauda equina was discovered in a 32-year-old man presenting with radiculopathic back pain and lower-extremity weakness. An intracranial pPNET that mimicked a meningioma was found in a 21-year-old man presenting with headache and visual disturbances. MIC2 gene product expression and EWS/ETS gene rearrangement were detected in both case patients. The literature with regard to pPNETs/ESFTs arising within the craniospinal vault is reviewed.     

骨外Ewing肉瘤/外周原始神经外胚叶肿瘤的临床病理分析

目的探讨骨外Ewing肉瘤／外周原始神经外胚叶肿瘤的临床病理特征及诊断、鉴别诊断依据。方法18例骨外Ewing肉瘤／外周原始神经外胚叶肿瘤行常规病理检查及免疫组化染色,其中2例进行电镜检查。结果光镜显示肿瘤组织主要由小圆形或卵圆形细胞组成,免疫组化染色显示肿瘤细胞膜CD99强阳性,电镜显示肿瘤细胞质内有神经内分泌颗粒。结论骨外Ewing肉瘤/外周原始神经外胚叶肿瘤的诊断依赖病理特征,并需要与其他小细胞恶性肿瘤进行鉴别。     

Primary vulvar Ewing's sarcoma/primitive neuroectodermal tumor in a post-menopausal woman: A case report

Ewing's sarcomas/peripheral primitive neuroectodermal tumors (ES/pPNETs) are high-grade malignant neoplasms rarely found outside the skeletal system. Only 12 cases of vulvar ES/pPNET have so far been reported, all involving children or women of child-bearing age. We describe the case of a 52-year-old woman who was admitted to our hospital for the local excision of a 4 cm vulvar mass, originally thought to be a Bartholin's gland cyst. It was subsequently found to consist of small round cells positive for anti-CD99 antibody, thus suggesting a diagnosis of ES/pPNET. The demonstration of EWSR1 gene translocations by means of fluorescent in situ hybridization excluded small-cell carcinoma, squamous cell carcinoma of the small type, Merkel cell carcinoma, and lymphoblastic lymphoma. After surgery, the patient received six cycles of polychemotherapy and radiotherapy; she is still alive and well after 1 year of follow-up. Our findings underline the crucial role of molecular biology techniques in the differential diagnosis of small round cell tumors in these unusual locations.     

Ganglioneuromatous paraganglioma of the cauda equina--a pathological case study

This study presents a rare case of compound paraganglioma/ganglioneuroma with comprehensive immunohistochemical studies that reveal strong cytokeratin expression in all components. A 74-year-old woman presented with a mass lesion of the cauda equina. The 1.8-cm tumor showed 3 histomorphologically and immunohistochemically distinct components: typical paragangliomatous neuroendocrine areas, mature ganglion cell-like neuronal areas, and a "neuromatous" proliferation of Schwann cells with admixed axons. As often seen in cauda equina paragangliomas, the neuroendocrine cells were cytokeratin-positive. In addition, immunoreactivity for cytokeratins was also observed in the neurons and axons. This tumor illustrates the broad spectrum of divergent differentiation that can be seen in cells of sympathoadrenal lineage.     

Distribution of neurofilament protein and neuron-specific enolase in peripheral neuronal tumours

Summary Peripheral neuronal tumours were studied by the peroxidase-antiperoxidase (PAP) method for the presence of the neurofilament protein (NFP) and neuron-specific enolase (NSE). All cases of ganglioneuromas and ganglioneuroblastomas were positive for NFP and NSE. Both markers were observed only in tumour cells showing differentiation towards ganglion cells. Of the 14 cases of neuroblastoma, 8 were positive for NFP and 12 were positive for NSE. NSE was detected in most neuroblastic tumour cells. However, NFP was found in neuroblasts with signs of differentiation, such as nuclear enlargement, but not in immature, small round cells. NFP was present in cell bodies as well as in cytoplasmic processes of partially differentiated neuroblasts. The majority of pseudorosettes showed no NFP stain. Thus, antibodies against both NFP and NSE are useful in the diagnosis of peripheral neuronal tumours. Moreover, the presence of NFP seemed to be related to the degree of tumour cell differentiation.     

Primary intracranial Ewing’s sarcoma with unusual features

Pediatric primary “small round blue cell” tumors in the CNS represent several entities, some more common than others. Ewing sarcoma/peripheral primitive neuroectodermal tumor (ES/pPNET) is rare and must be distinguished from other tumors such as medulloblastoma [1, 2], atypical rhabdoid/teratoid tumor, ependymomal tumors, metastatic sarcomas, hematologic malignancies, and other mimics. Although therapy for ES/pPNET is effective, it brings severe side effects, including cardiac toxicity, making correct recognition important [3]. As small blue cell tumors look similar, diagnosis often depends on special stains, immunohistochemistry, and molecular techniques. While the combination of membranous immunohistochemical reactivity for CD99 with cytoplasmic glycogen provides effective screening, demonstration of characteristic translocations of EWSR1 (chromosome 22) or FUS (chromosome 16) by fluorescent in situ hybridization (FISH) can confirm the diagnosis. We are reporting three primary ES/pPNET of the CNS, two of which occurred in children. While the adult case demonstrates the classic histopathology, the two pediatric cases have histopathology that significantly deviates from the usual. One is suggestive of a primary sarcoma, and the other mimics an ependymoma, but all three cases are confirmed with FISH. These observations suggest that primary ES in the CNS may have histology different from the classic morphology and a high index of suspicion should be maintained in order to make the correct diagnosis. A search of the literature suggests that these tumors are most frequently seen in children and young adults. Imaging often shows a supratentorial enhancing mass that touches the leptomeninges. Survival over three years is good but long term prognosis is unknown [3, 4].     

石蜡包埋尤文瘤/外周原始神经外胚瘤中EWS-FLI1融合基因的表达

目的 运用逆转录聚合酶链反应(RT-PCR)技术检测石蜡包埋尤文瘤／外周原始神经外胚瘤(ES／pPNET)组织中特异性染色体易位融合基因EWS-FLI1／ERGmRNA的表达并探讨其诊断意义。方法 运用一步法RT-PCR技术检测25例石蜡包埋ES／pPNETs和15例其他小圆细胞肿瘤(包括8例胚胎型和腺泡型横纹肌肉瘤、4例低分化滑膜肉瘤、2例神经母细胞瘤和1例淋巴瘤)组织中EWS-FLI1／ERG的表达。结果 25例ES／pPNET中20例检测到EWS-FLI1／ERG融合基因的表达(8056),15例对照组均未检出EWS-FLI1的表达。结论 EWS-FLI1／ERGmRNA的表达是ES／pPNETs分子诊断的可靠指标,一步法RT-PCR是一种适用于临床常规石蜡包埋组织EWS-FLI1融合基因表达的检测方法。     

Aggressive oncocytic neuroendocrine tumour (''oncocytic paraganglioma'') of the cauda equina

An oncocytic neuroendocrine tumour ('oncocytic paraganglioma') of the cauda equina is reported. The tumour was predominantly intradural, with extension into and destruction of surrounding vertebral bone. The tumour had an organoid pattern, and the tumour cells had abundant non-argyrophilic eosinophilic cytoplasm. Immunocytochemical stains for neurone-specific enolase, S-100 protein, keratin and carcinoembryonic antigen were positive, but stains for glial fibrillary acidic protein were negative. On ultrastructural examination, there were numerous mitochondria and scattered 200 nm dense-core membrane-bound granules, that rarely clustered in small aggregates. Intermediate filaments were focally arranged in long compact bundles. The histogenesis of tumours reported as cauda equina paragangliomas is discussed.     

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.     

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 ultra-structural 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 immunore-activities 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 undifferentiatied 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 neuroectodermal differentiation and some histological variations. Acta Pathol Jpn 41: 444–454, 1991.     

Peripheral neuroepithelioma: a light microscopic, immunocytochemical, and ultrastructural study.

Forty-two cases of peripheral neuroepithelioma (PN) retrieved from the files of the National Cancer Institute (Bethesda, MD) and the Pathology Department of Padua University, Italy, were reviewed. No sex predilection was observed (25M/17F) and ages ranged from 7 to 54 yr (median 22 yr). Roughly a third of the tumors were thoracopulmonary ("Askin tumor"), a third were axial, and a third were in extremities. A lobular pattern with rosettes or pseudo-rosettes characterized PN. Seventeen cases showed a strong diastase-sensitive PAS positivity. Transitional areas with an Ewing's-like appearance and, in one case, transition to malignant nerve sheath tumor have been documented. The presence of neuron specific enolase (NSE), S-100 protein, HNK-1, neurofilaments, vimentin, keratin (AE1-AE3), beta 2-microglobulin, chromogranin A, and synaptophysin was investigated using the avidin-biotin technique. Immunocytochemically, NSE (95% of cases), beta 2-microglobulin (77.5%), synaptophysin (73.3%), and S-100 protein (67.5%) were the most consistently positive markers. Ultrastructurally, PN is characterized by a primitive appearance, although it was routinely possible to recognize neural features such as primitive neuritic extensions and dense core granules, either in the cytoplasm or in the cellular processes. In our experience, a light microscopic picture of a primitive round cell tumor with a lobular pattern, and particularly with rosettes when present, with NSE and beta 2-microglobulin positivity by immunocytochemistry, ideally with positive synaptophysin, along with supportive electron microscopy, is required for the diagnosis of PN. Conversely, no one feature alone is generally sufficient for diagnosis, but does allow distinction from extraosseous Ewing's, which (like osseous Ewing's) lacks features of neural differentiation.     

Ewing family tumours: a paediatric perspective

Sarcomas are malignant tumours of the connective tissues and are proportionately much more common in children than in adults. The Ewing family of tumours (EFT) is a group of sarcomas sharing rearrangement of the EWSR1 gene on 22q12, and include Ewing sarcoma/primitive neuroectodermal tumour, desmoplastic small round cell tumour, angiomatoid fibrous histiocytoma and clear cell sarcoma. Other tumours harbouring EWSR1 rearrangements include myoepithelial tumours, myxoid liposarcoma and extraskeletal chondrosarcoma. In addition, a group of Ewing-like primitive round cell sarcomas have been recently described in a paediatric population, further expanding the list of EFT. This review will focus on the histopathological, immunohistochemical and molecular genetic features of EFT, with an emphasis on those predominantly occurring in the paediatric population.     

Gastrointestinal haemorrhage from a jejunal gangliocytic paraganglioma.

A case of jejunal gangliocytic paraganglioma is reported in a 54 year old woman who presented with brisk melaena. The tumour was not encapsulated, involved the mucosa and submucosa, and was composed of epithelial nests, spindle cells, and ganglion cells. These cells were mixed, giving carcinoid-like, paraganglioma-like, and ganglioneuroma-like patterns in different areas of the tumour. The lesion was excised locally and recovery was uneventful. Only four previous cases have been reported at this site.     

肺原发性软骨肉瘤2例及文献复习

目的：探讨肺原发性软骨肉瘤的临床病理特征及组织发生。方法：通过ＨＥ、组化及免疫组化观察２例肺原发性软骨肉瘤,并复习文献。结果：肿瘤由粘液亲基质和疏网状结构的梭形细胞及软骨母细胞组成,例２还存在幼稚小圆细胞,三种细胞梯度移行。组化染色显示ＡＢ（ｐＨ２．５）、ＴＢ（ｐＨ４．０）阳性。免疫组化染色显示梭形细胞及软骨母细胞Ｓ－１００蛋白、ｖｉｍｅｎｔｉｎ和ＮＳＥ阳性,例２Ｓｙｎ阳性。小圆细胞ＣＤ９９、Ｓ－     

A comparative study of immunohistochemical staining for neuron-specific enolase, protein gene product 9.5 and S-100 protein in neuroblastoma, Ewing's sarcoma and other round cell tumours in children

A comparative study of immunohistochemical staining for neuron-specific enolase (NSE), protein-gene product 9.5 (PGP 9.5) and S-100 was made in 71 undifferentated round cell tumours from 65 children using formalin-fixed tissues and a standard alkaline phosphatase-anti-alkaline phosphatase method. All of 29 neuroblastomas marked for NSE and 27 for PGP 9.5; staining was diffuse and usually strong in all tumour elements, irrespective of the degree of differentiation. Patterns of staining remained consistent in primary, recurrent and metastatic tumours and were not modified by previous chemotherapy. S-100 staining was weak and confined to cell processes and schwannian elements in less than half of the tumours studied. Two primitive neuroectodermal tumours both stained strongly for NSE and PGP 9.5. Staining for NSE was observed in single maturing cells in 3/12 rhabdomyosarcomas and in tubular elements in 2/4 Wilms' tumours; primitive rhabdomyoblasts and undifferentiated renal blastema were negative; seven lymphomas were negative. Six of 17 skeletal Ewing's sarcomas showed light to moderate cytoplasmic staining for NSE and PGP 9.5. The site, histology and clinical course of these marker-positive Ewing's sarcomas showed no distinctive features. Staining for PGP 9.5 is a useful additional marker for neural differentiation in round cell tumours.     

An immunohistological study of 66 ependymomas

Sixty-six ependymomas were examined immunohistologically to determine their distribution of glial fibrillary acidic proteins, S-100 protein and vimentin. The neoplasms were subdivided into four groups: (1) ependymomas from the cauda equina, predominantly of the myxopapillary type; (2) benign ependymomas; (3) malignant ependymomas; and (4) ependymoblastomas. Marked differences in antigen reactivity were observed between each group. The intensity of the reaction with the three antibodies was strongest in malignant ependymomas. Ependymomas from the cauda equina showed a patchy distribution of positivity for the three antigens in cells surrounding blood vessels but there was no staining of collagenous septa or the myxoid areas. In ependymoblastomas, the cells of the rosettes were negative for glial fibrillary acidic protein, but there was focal positivity for vimentin and S-100. Other areas showed tumour cells containing moderate amounts of vimentin and small amounts of S-100, and a few bands of filaments positive for glial fibrillary acidic protein. The cytogenetic and biological implications of these findings are discussed.     

马尾神经受压大鼠脊髓圆锥神经元的形态、凋亡及脑源性神经营养因子 mRNA的表达变化

目的 观察大鼠马尾神经受压后脊髓圆锥神经元的形态变化,检测脊髓神经元凋亡数量及脑源性神经营养因子(BDNF)mRNA的表达,以及探讨上述变化的可能机制. 方法 将90只成年SD大鼠分为马尾受压模型组、假手术组与正常对照组,分别于造模术后30min、2h、4h、8h、1d、3d、1周、2周、3周取样.采用光镜与透射电镜观察马尾受压后脊髓圆锥神经细胞的形态变化;采用原位缺口末端标记(TUNEL)技术检测细胞凋亡;原位杂交法测定BDNF mRNA阳性细胞的数量.计算单位面积内的阳性细胞数,单因素方差分析比较马尾受压后不同时间组与对照组之间的差异. 结果 马尾神经受压可导致脊髓圆锥神经元形态结构出现明显伤害性改变.TUNEL染色与BDNF mRNA原位杂交显示,阳性细胞分别于制模术后8h、4h起较对照组有明显增多,并于术后3d达高峰,术后3周上述阳性细胞的数量仍明显高于对照组. 结论 马尾神经受压后,可导致相应脊髓圆锥神经细胞结构的明显变化,其凋亡数量明显增加,说明马尾受损可导致中枢神经元的不可逆损伤,这可能是马尾综合征逾期手术效果不理想的重要原因之一.在马尾严重受压后,神经元及胶质细胞的BDNFmRNA的表达明显增加,可能对神经细胞的保护及修复起一定作用.