Malignant peripheral neuroectodermal tumours of childhood and adolescence

Summary Seventeen cases of malignant peripheral neuroectodermal tumour (MPNT) were studied by means of light microscopy, immunohistochemistry and electron microscopy. There were nine males and eight females. The mean age of the 17 patients was 10 years with a range of seven months to 20 years. The vast majority of tumours was located in the trunk. Histologically, they closely resembled Ewing's sarcoma, although minor differences were obvious. Special findings included ganglion cells and Flexner rosettes. In 10/11 cases positive staining for neuron-specific enolase (NSE) was obtained. Five of 10 tumours were positive for protein S-100. Three contained vimentin, two neurofilaments and one vimentin, neurofilaments and GFAP. Neurosecretory granules were noted in the three cases studied. Five patients died, three are alive with disease and five patients are alive without evidence of disease. It is concluded that these tumours form a homogeneous group, although the grade of differentiation varies. The prognosis in most cases is poor. Distinction from Ewing's sarcoma is possible by staining for NSE and by electron microscopy.This study was supported in part by a grant from the Bundesminister für Arbeit und Sozialordnung     

外周性原始神经外胚层瘤的形态及免疫组化观察

目的 :观察外周型原始神经外胚层瘤 (pPNET)的临床病理及免疫组化特征。 方法 :对 10例 pPNET进行组织形态学观察及免疫组织化学和组织化学染色。结果 :形态学上表现为小圆细胞性呈大片状排列 ,其间可见纤维结缔组织间隔 ,瘤细胞呈非典型性菊形团样结构 ;免疫组化显示NSE呈 10 0 %表达 ,Syn、S 10 0蛋白和Vim分别为 80 % (8/ 10 )、6 0 % (6 / 10 )和6 6 7% (6 / 9)。结论 :根据临床表现、组织形态学特征及其免疫组化表型有助于 pPNET的诊断。     

Primitive neuroectodermal tumors of bone and soft tissue: Histological subclassification and clinicopathologic correlations

Recent reports of Ewing's sarcoma (EW) and extraskeletal Ewing's sarcoma (EEW) support the hypothesis that these tumors are neuroectodermal in origin. Primitive neuroectodermal tumors (PNET) of bone (32 cases) and soft tissue (25 cases) includiong those previously categorized as EW in 27 cases and EEW in 15 cases were carefully studied histologically, immunocytochemically and morphometrically, focusing on tumor cell differentiation. This study attempts to subclassify these tumors on the basis of the size of tumor cells and nuclei, their variations (uniformity or diversity), arrangement of tumor cells (rosette or non-rosette), focal differentiation to larger ganglion-like cells, and staining intensity for neural markers. All tumors were histologically subclassified as small, medium or large cell types, three basic subtypes (rosette type, abortive rosette type, non-rosette type) and four complementary subtypes (fibrillary type, non-fibrillary type, angiomatoid type, ganglion cell type). Classic EW or EEW is consistent with small or medium, non-rosette, non-fibrillary type tumors, previously described large cell EW with large, non-rosette, fibrillary or non-fibrillary type tumors, and classic neuroectodermal tumor with small or medium rosette, fibrillary type tumors, according to the present subclassification. Clinicopathologic correlations with the different subtypes are discussed. Long-term survival, more than 5 years, was seen in patients with small cell type, and those younger than 14 years of age.     

Malignant peripheral nerve sheath tumors in neurofibromatosis 1

One of the most clinically aggressive cancers associated with neurofibromatosis 1 (NF1) is the malignant peripheral nerve sheath tumor (MPNST). To determine the incidence and relative risk (RR) of MPNSTs in individuals with NF1, 1,475 individuals with NF1 were included from a cohort of patients examined by a single experienced geneticist from 1977 to 1996. The end points were incidence of MPNST, relative risk of MPNST, and relative risk associated with specific NF1 physical findings. Thirty-four individuals were identified with MPNST (2%). The relative risk of MPNST was higher than expected with an RR value of 113 (95% confidence interval [CI] = 78-158). The average 10-year annual incidence of MPNST between the second and fifth decade of life was roughly the same with a range of 0.0013 and 0.0068 MPNST per patient year. Most lesions occurred in the limbs (n = 18; 53%), and those with limb lesions survived longer than those with nonlimb MPNSTs. Pain associated with a mass was the greatest risk factor associated with MPNST development (RR = 31.4; 95% CI = 13.2-75.1). Further biological and epidemiological studies are needed to determine other factors that influence the risk of MPNST development in individuals affected with NF1. Am. J. Med. Genet. 93:388-392, 2000. Published 2000 Wiley-Liss, Inc.     

Cytologic characteristics of peripheral neuroectodermal tumors in fine-needle aspiration smears: A retrospective study of three pediatric cases

Cytologic diagnosis of peripheral neuroectodermal tumors (PNT) on fine-needle aspiration (FNA) smears represents a challenge to the cytopathologist. Usually ancillary studies are used to achieve definitive diagnosis. We retrospectively examined FNA material from three cases of PNT with the aim of identifying their features. Positive and negative cytologic findings were recognized. Positive features for PNT included the presence of: rather uniform appearance of the cells, which display scant but almost always-present perinuclear clear cytoplasm (suggesting a bland epithelial tumor); nuclei with distinctively smooth nuclear membrane contour, finely granular chromatin, and one or two small nucleoli (suggesting neuroendocrine anlage); and organization of the cells singly or in cohesive clusters. Negative findings included the absence of: frequent mitotic figures, large nucleoli, nuclear pleomorphism, cellular debris, histiocytes, and polymorphonuclear leucocytes. The smears appeared clean, with small, uniform cells having features suggesting a neuroendocrine epithelial tumor. These findings may prove useful for accurate cytologic diagnosis and differentiation of PNT from other small blue round cell tumors (SBRCT) of soft tissues without the use of ancillary studies since, when properly evaluated, cytomorphology of the latter group of tumors is more heterogeneous than generally believed. Diagn. Cytopathol. 16:513–517, 1997. © 1997 Wiley-Liss, Inc.     

Histological evolution of peripheral T-cell lymphomas. Study of six cases.

The authors report 6 cases of histological transformation in peripheral T-cell lymphomas of low grade of malignancy. The transformation occurs in 75% of the cases, in extra-nodal sites and corresponds to a monomorphic of pleiomorphic large cell type. There is no discordance in the immunologic results between the two phases. The transformation seems to occur earlier than in B lymphomas, with a relative frequency of hematological manifestations and no therapeutic response.     

Primitive neuroectodermal tumors of the uterus: a report of four cases.

Four cases of primitive neuroectodermal tumor (PNET) of the uterine corpus are reported, bringing the total number of reported PNETs in this site to seven. The four women were in their seventh decade of life and presented with abnormal vaginal bleeding and, in two cases, an enlarged uterus. The patients underwent total or subtotal abdominal hysterectomy and bilateral salpingo-oophorectomy and, in one patient, pelvic lymphadenectomy. Three patients received postoperative radiation therapy, chemotherapy, or both. Gross examination revealed fleshy polypoid masses filling the endometrial cavity and, in two cases, deeply invading the myometrium. Histologic, immunohistochemical, and, in two cases, ultrastructural examination revealed typical PNETs that exhibited variable degrees of neural, glial, ependymal, and medulloepithelial differentiation. Two PNETs were admixed with other neoplasms: in one case a grade I endometrial adenocarcinoma and in the other a low-grade endometrial stromal sarcoma. The prognosis of the tumors was related to their stage: two patients with stage I tumor were alive with no evidence of disease at 5 and 6 years, whereas two patients with stage III or IV tumor died of tumor at 6 and 12 months. Although it has been suggested that uterine PNETs may be derived from displaced germ cells or implanted fetal tissues, evidence provided by this study, including the advanced ages of the patients and an admixture with neoplasms of unquestioned müllerian origin, suggests a müllerian origin for these tumors in at least some cases.     

原发椎管内外周型原始神经外胚层肿瘤2例

目的探讨椎管内原发外周型原始神经外胚层肿瘤的临床特点、诊断、病理表现和治疗进展。方法分析2例经影像学、手术和病理检测证实的椎管内原始神经外胚层肿瘤,回顾相关文献,总结其临床特点。结果 2例病变术前行MRI检查呈等T1WI和等T2WI信号,增强后明显强化;镜下部分切除病变,术后病理检查提示均为外周型原始神经外胚层肿瘤,术后行放疗和化疗,分别随访13和10个月。结论椎管内原始神经外胚层肿瘤发病率低,好发于青少年,影像学无明显特异性,病理检查是可靠的诊断依据,预后较差。     

Malignant peripheral neuroectodermal tumours of bone other than Askin's neoplasm: characterization of 14 new cases with immunohistochemistry and electron microscopy

Summary Peripheral neuroectodermal tumours (PNET) of bone are rare and mimick those seen in soft tissue (peripheral neuroepithelioma of soft tissue). Their differential diagnosis from Ewing's sarcoma (Es) is extremely difficult by optical means. Here we report 14 new cases of PNET of bone (other than Askin's neoplasm) located primarily in the limbs, pelvic girdle and scapula. Clinically and radiologically they displayed Ewing's sarcoma-like features: mean age was 14.4 years, male/ female ratio being 3:11. Metastasis was present in 6 cases at diagnosis (5 with bone metastasis). Prognosis was poor; thirteen patients died; only one with a metatarsal located tumour is alive and free of disease. The mean survival rate was 25 months following diagnosis and treatment with radio- and multimodal chemotherapy. Histologically the 14 cases displayed Homer-Wright rosettes and pseudorosette-like structures, as well as a fibrillary background and lobular pattern. Immunohistochemistry revealed positivity in a number of neural markers when using paraffin-embedded material: NSE, B-2-microglobuline, HNK-1 (leu-7) and E-36 antibodies. At EM level the cell cytoplasms evidenced dense-core granules with neurosecretion, neurotubules and intermediate filaments like those seen in peripheral neuroepithelioma.This work has been supported by a grant (No. 83/058) from the US/Spain Joint Committee for Scientific and Technological Cooperation     

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.     

Intracranial peripheral primitive neuroectodermal tumors of the cavernous sinus: a diagnostic peculiarity

Peripheral primitive neuroectodermal tumors (pPNETs) are aggressive, poorly differentiated neoplasms that occur in children and young adults. These tumors are associated with a peak incidence in the second decade and a slight male preponderance. Recently, Ewing sarcoma and pPNET tumors have been proven to carry identical translocations, the most common being t(11;22)(q24;q12). Intracranial Ewing sarcoma/pPNETs have rarely been described in the literature. We studied a case of intracranial pPNET arising in the right cavernous sinus of a 46-year-old man. On imaging, the tumor had both sellar and suprasellar components and was centered within the right parasellar region. Histologically, the tumor was composed of intermediate to large cells with round to oval hyperchromatic nuclei with distinct nucleoli. The cells contained a moderate amount of slightly basophilic cytoplasm. The tumor was markedly fibrotic and had collagen bands surrounding both individual and groups of cells. A large immunohistochemical panel was positive only for CD99 and vimentin. Fluorescence in situ hybridization did not show translocations associated with Ewing sarcoma/pPNET. However, a small percentage of these tumors can be negative for this translocation. In these cases, histology and immunohistochemical techniques in the absence of an alternative diagnosis are the only tools available to establish the diagnosis.     

Expression of a new human THY-1 related antigen in Ewing's sarcoma and peripheral neuroectodermal tumors

Ewing's sarcoma (ES), peripheral neuroectodermal tumor (PNET) and Askin's tumor of the chest wall share a reciprocal chromosomal translocation between the long arms of chromosomes 11 and 22 (q23-24; q12). In the absence of other distinguishing features this specific translocation is regarded as marker of a common and neuroectodermal origin for these rare tumors. A monoclonal antibody (HBA-71) developed in our laboratory has been found to recognize an unique ES and PNET associated antigen, which is also expressed in some normal tissues, including thymus, bone marrow, islets of Langerhans, ependyma and adenohypophysis. It is shown in this study that this HBA-71 antigen is closely related to the murine THY-1 antigens, major cell surface glycoproteins of thymocytes and brain in mice and rat. Both antigens have similar molecular ratios (18,000), amino acid compositions and sensitivity to tryptic digestion, show high cell surface expression, and binding of the appropriate antibodies to HBA-71 antigen triggers proliferation in thymocytes. The HBA-71 epitope may represent a primitive neuroectodermal marker of ES/PNET, or its expression may be directly linked to the reciprocal translocation invariably associated with HBA-71-positive ES and PNET tumors, which maps to the same region of chromosome 11 (q23-24) as the human Thy-1 gene.     

41例心脏和心包肿瘤的临床病理分析

目的通过对４１例心脏和心包肿瘤的病理学研究，分析其病理改变与预后的关系。方法用组织化学染色观察。结果良性瘤３９例，占９５．１％，包括粘液瘤、纤维瘤、横纹肌瘤；恶性瘤２例，占４．９％，包括神经纤维肉瘤、恶性间皮瘤。在粘液瘤中７５％为女性患者，９１．７％发生在左心房内。结论心脏肿瘤与其他部位的肿瘤不同，既是良性瘤也可引起血液动力学改变而致命，需早期诊断和手术治疗；恶性瘤预后极差。