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Ovarian neoplasms composed of small round cells: a review.

Ovarian neoplasms composed predominantly or exclusively of small round cells with scant cytoplasm are relatively rare. However, there is a wide differential, and pathologists often struggle to make a correct diagnosis because of overlapping histologic features. Perhaps the best known of these neoplasms is ovarian small cell carcinoma of hypercalcemic type (OSCCHT), a tumor of unknown histogenesis. This may be confused with a wide range of neoplasms ranging from sex cord-stromal tumors (some of which may exhibit a small cell phenotype) to neoplasms in the family of small round blue cell tumors to various undifferentiated malignancies. A neuroendocrine small cell carcinoma, so-called small cell carcinoma of pulmonary type, may also arise within the ovary, and this may be a component of a typical ovarian surface epithelial-stromal tumor. In addition to the well-known family of small round blue cell tumors of childhood, other small cell neoplasms that may arise within the ovary or involve the ovary include intra-abdominal desmoplastic small round cell tumor, metastatic small cell carcinoma, peripheral and central primitive neuroectodermal tumor, and endometrial stromal sarcoma. Malignant melanoma, undifferentiated carcinoma, and various germ cell tumors, especially dysgerminoma and immature teratoma, also on occasion enter into the differential diagnosis of an ovarian small cell neoplasm. In this review, the morphologic features of some of these neoplasms are described, as is the value of immunohistochemistry and other ancillary techniques in establishing a diagnosis.

Abdominal Neoplasms↗

Diktyoma.

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Humans↗

Diktyoma.

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Humans↗

Immunohistochemical detection of nestin in pediatric brain tumors.

Nestin is an intermediate filament protein (IFP) expressed in undifferentiated cells during CNS development and in CNS tumors. Previous studies have arrived at different conclusions in terms of which types of CNS tumors express nestin. In this report we establish an immunohistochemical protocol using antigen retrieval, which significantly enhances staining with two polyclonal anti-nestin antisera, #130 and #4350. The staining pattern was identical for the two nestin antisera and very similar to that of vimentin, while glial fibrillary acidic protein (GFAP), immunoreactivity was absent from 9.5-week-old forebrain. The current study of 20 primary CNS tumors from pediatric patients included seven ependymomas, seven primitive neuroectodermal tumors (PNETs), five pilocytic astrocytomas, and one glioblastoma multiforme (GBM). All these tumors expressed nestin to various extents, in contrast to five brain metastases tested. Strong nestin immunoreactivity was found in malignant primary CNS tumors, whereas benign pilocytic astrocytomas showed low but consistent nestin expression. In all tumors nestin immunoreactivity was confined to the cytoplasm of tumor cells and was co-expressed with astrocyte markers vimentin, GFAP, and S-100. Vascular endothelial cells of all neoplasms also showed marked immunoreactivity for nestin and vimentin, whereas they were negative for GFAP and S-100. In conclusion, antiserum #4350 detected nestin in formalin-fixed, paraffin-embedded tissue sections by heat-induced antigen retrieval immunohistochemistry. Nestin was expressed in both highly malignant and low malignant gliomas, indicating the potential use of nestin as a diagnostic tumor marker in surgical pathology.

Adolescent↗

Expression of myogenic regulatory proteins (myogenin and MyoD1) in small blue round cell tumors of childhood.

The distinction of rhabdomyosarcoma (RMS) from other small blue round cell tumors of childhood, such as Ewing's sarcoma/peripheral primitive neuroectodermal tumor (pPNET) and neuroblastoma, continues to present a diagnostic challenge to pathologists. The recent recognition of the master role of myogenic regulatory proteins in skeletal muscle commitment and differentiation, and the availability of monoclonal antibodies to two of them (myogenin and MyoD1), has prompted us to test their diagnostic utility in routinely processed, formalin-fixed, and deparaffinized tissue. Preliminary studies had demonstrated that, with the use of heat-induced epitope retrieval techniques, expression of myogenin and MyoD1 could be documented specifically in nuclei of fetal skeletal muscle by the respective antibodies. We performed a retrospective immunohistochemical analysis on 72 cases of small blue round cell tumors, including 33 RMSs, 1 metastatic myogenous Wilms' tumor, 26 Ewing's sarcomas/pPNETs, and 12 neuroblastomas. Nuclear expression of myogenin and MyoD1 were both found in 30/33 non-overlapping cases of RMS, with no significant differences in the sensitivity with respect to histological subtypes, and in 1/1 case of myogenous Wilms' tumor. None of the neuroblastomas or Ewing's sarcomas/pPNETs demonstrated positive nuclear staining with either antibody. However, most of the neuroblastomas, and occasional Ewing's sarcomas/pPNETs, showed variable fibrillary, cytoplasmic immunoreactivity with antibody to MyoD1. We conclude that, with the use of microwave-based epitope retrieval, antibodies to myogenin and MyoD1 are both useful markers for the identification of RMS among other small blue round cell tumors of childhood, but antibodies to myogenin have technical advantages over those to MyoD1, as the latter may cross-react with an unknown cytoplasmic antigen in non-muscle cells and tumors.

Child↗

[Mediastinal neuroectodermal tumor. Apropos of a case].

Peripheral malignant neuroectodermal tumors are rare and aggressive small-cell tumors seen predominantly in children and young adults. Mediastinal location is very uncommon. A mediastinal primitive neuroectodermal tumor was diagnosed in a 27-year-old man. Despite treatment combining surgery, radiotherapy and chemotherapy, disease recurred locally along with lungs, spinal and epidural metastases, leading to death. CT and MRI examinations show heterogeneous masses with necrosis, hemorrhage and intense enhancement after Gadolinium injection. The CT and MRI findings are not specific and the diagnosis is based on pathologic, immunohistochemical and electron microscopic features. Although uncommon, peripheral neuroectodermal tumor should be considered in the differential diagnosis of posterior mediastinal masses in children and young adults.

Adult↗

Pediatric brain tumors express multiple receptor tyrosine kinases including novel cell adhesion kinases.

We have used the polymerase chain reaction to clone and characterize growth factor receptor tyrosine kinases (RTKs) expressed in 3 pathologically distinct pediatric brain tumors, an anaplastic ependymoma, a glioblastoma multiforme and a primitive neuroectodermal tumor (PNET). These neoplasms are presumed to be derived from embryonic neuroepithelial precursor cells of the central nervous system. This cloning demonstrated expression of 24 distinct kinase genes: 16 receptor type kinases and 8 nonreceptor type kinases. The expression of 6 receptors, including Hek2, IRR, Ryk, FGFR3, and 2 members of the newly identified cell adhesion kinase receptor family, DDR and TKT, in such tumors has not been reported previously. Northern analysis of mRNA levels revealed DDR expression in 6 of 7 pediatric brain tumors including an ependymoma, PNET, glioblastoma and astrocytoma, and also in an adult pheochromocytoma. Thus, the DDR cell adhesion kinase may be widely expressed in pediatric brain tumors. Also, PCR cloning may be an effective procedure for characterizing RTKs in clinical tissue samples and revealing the expression of novel RTK species.

Adrenal Gland Neoplasms↗

Treatment of progressive or recurrent pediatric malignant supratentorial brain tumors with herpes simplex virus thymidine kinase gene vector-producer cells followed by intravenous ganciclovir administration.

OBJECT: The outcome for children with recurrent malignant brain tumors is poor. The majority of patients die of progressive disease within months of relapse, and other therapeutic options are needed. The goal of this Phase I study was to evaluate the safety of in vivo suicide gene therapy in 12 children with recurrent, malignant, supratentorial brain tumors. METHODS: After optimal repeated tumor resection, multiple injections of murine vector-producing cells shedding murine replication-defective retroviral vectors coding the herpes simplex virus thymidine kinase type 1 (HSV-Tk1) gene were made into the rim of the resection cavity. Fourteen days after the vector-producing cells were injected, ganciclovir was administered for 14 days. The retroviral vector that was used only integrated and expressed HSV-Tk1 in proliferating cells, which are killed after a series of metabolic events lead to cell death. The median age of the patients was 11 years (range 2-15 years). Treated brain tumors included seven malignant gliomas, two ependyminomas, and three primitive neuroectodermal tumors. The patients were treated with one of three escalating dose concentrations of vector-producer cells. Four transient central nervous system adverse effects were considered possibly related to the vector-producing cells. In no child did permanent neurological worsening or ventricular irritation develop, and tests for replication-competent retroviruses yielded negative findings. CONCLUSIONS: This Phase I study demonstrates that in vivo gene therapy in which a replication-defective retroviral vector in murine vector-producing cells is delivered by brain injections can be performed with satisfactory safety in a select group of children with localized supratentorial brain tumors.

Adolescent↗

Pineal tumors: analysis of treatment results in 20 patients.

OBJECT: The authors evaluate their results when using gamma knife surgery (GKS) in the management of patients with tumors in the pineal region. METHODS: This is a retrospective clinical evaluation of 20 patients with primary tumors of the pineal region treated with GKS from November 1994 through August 2003. There were 13 germ cell tumors, two pineoblastomas, two low-grade gliomas, one primitive neuroectodermal tumor, one teratoma, and one pineocytoma. There were 10 male and 10 female patients. Their median age was 15.5 years (range 5-71 years). The median margin dose was 11 Gy (range 8-20 Gy). The median target volume was 3.1 cm3 (range 0.1-49.9 cm3). Five patients received sequential systemic chemotherapy and four underwent adjuvant conventional radiation therapy. Seventeen (85%) of 20 patients are alive with a median survival of 30.4 months (range 0-85.7 months). Two patients required retreatment. Three patients died: one of unrelated causes, one who presented with extensive local disease, and the other of meningeal carcinomatosis with local control of the primary tumor. No complications from GKS were noted. CONCLUSIONS: This initial experience suggests that GKS is a valuable treatment modality for the management of pineal region tumors. This technique offers excellent local tumor control and minimal patient morbidity, allowing for immediate use of systemic chemotherapy and/or conventional radiation if indicated.

Adolescent↗

[Atypical teratoid and rhabdoid tumor. Report of a congenital case].

The atypical teratoid rhabdoid tumor is a rare brain tumor of childhood. We report a congenital case, revealed by peripheral facial palsy. This polymorphous tumor consisted of rhabdoid cells associated with areas of primitive neuroectodermal tumor. The immunoreactivity for the three proteins vimentin, epithelial membrane antigen and smooth-muscle actin was suggestive of rhabdoid tumor. Genetic study showed a homozygous mutation in the tumoral DNA and a constitutional heterozygous mutation, as it was demonstrated in atypical teratoid rhabdoid tumors and in renal and extra-renal rhabdoid tumors.

Actins↗

Biphenotypic sarcomas with myogenic and neural differentiation express the Ewing's sarcoma EWS/FLI1 fusion gene.

Accurate diagnosis of primitive childhood sarcomas continues to be a formidable problem because these malignancies generally demonstrate very little morphological evidence of their tissue of origin. One of these tumor classes, the Ewing's sarcoma family of peripheral primitive neuroectodermal tumors (pPNETs), are thought to have a neural histogenesis based on evidence of neuroectodermal differentiation. Greater than 95% of pPNETs carry t(11;22) or t(21;22) chromosomal translocations which fuse the EWS gene from chromosome 22q12 in-frame with either FLI1 from chromosome 11q24 or ERG from chromosome 21q22. The pPNETs are considered to be histogenetically distinct from rhabdomyosarcomas, myogenic tumors lacking these EWS gene fusions and hypothesized to derive from immature skeletal muscle precursors. In the present study, we describe a unique set of childhood soft tissue sarcomas that show both neural and myogenic differentiation. These biphenotypic tumors express myogenic regulatory factors and muscle-specific antigens and also show neuroectodermal differentiation with ultrastructural evidence of neurosecretory granules and expression of neural-associated genes. Northern analysis and reverse transcriptase PCR reveal expression of EWS/FLI1 gene fusions in all biphenotypic sarcomas analyzed. Chimeric EWS/FLI1 transcripts and fusion proteins in these tumors are identical to those described for pPNETs. Our results provide evidence for a class of biphenotypic childhood sarcomas with myogenic and neural differentiation and suggest that these tumors may be related to the Ewing's sarcoma family of pPNETs.

Adolescent↗

Primary intracranial neoplasms of infancy and early childhood.

We investigated the age-related location, gender distribution, and histology of 107 brain tumors in children under 4 years of age seen in our department between 1984 and 1997. The male-to-female ratio was 1.4 (62/45 cases) with a prevalence of supratentorial tumors (60/47 = 1.3); the main histological entity was astrocytoma (33.6%), followed by ependymoma (14.0%). In the 1st year of life 22 cerebral neoplasms became clinically apparent. A higher ratio for supratentorial tumors was revealed (17/5 = 3.4), but without gender preference, and primitive neuroectodermal tumors (PNET) were the most frequent (5/22). In the 2nd year 25 tumors were found. The male-to-female ratio was 1.5 (15/10) and the supratentorial-to-infratentorial ratio, 1.1 (13/12). The two most common entities were astrocytoma and ependymoma (6 cases each). In addition, a survey of previously published investigations into this subject was performed and a compilation of data on 1960, 545 and 1084 tumors in children below the age of 1, 2 and 4 years, respectively, was prepared, which makes it the most extensive review of brain tumors of infancy and early childhood yet undertaken.

Age Factors↗

Overexpression of the hepatocyte growth factor (HGF) receptor (Met) and presence of a truncated and activated intracellular HGF receptor fragment in locally aggressive/malignant human musculoskeletal tumors.

Enhanced hepatocyte growth factor (HGF) receptor (Met) signaling has been suggested to play an important role in the development and progression of various epithelial and nonepithelial tumors. N-terminally truncated forms of the HGF receptor have been shown to be constitutively activated and tumorigenic in animal experiments. In the present study, 102 benign and malignant human musculoskeletal tumors were examined for expression of the HGF receptor by Western blotting and/or immunohistochemistry. A clear predominance of HGF receptor expression was seen in malignant as compared to benign tumors (Western blotting, P < 0.001; immunohistochemistry, P < 0.02). For the first time we show HGF receptor expression in the following four tumor types: dermatofibrosarcoma protuberans, clear cell sarcoma of tendons, malignant primitive neuroectodermal tumor, and benign fibrous histiocytoma. In three cases of sarcoma with high HGF receptor expression by Western blotting, we found indications of a short 85-kd N-terminally truncated HGF receptor that was tyrosine phosphorylated and located in the cytoplasm. Although fragments of this length were seen in 18 of 65 tumors, most were not tyrosine-phosphorylated. Northern blotting revealed only the 7.5-kb full-length HGF receptor transcript, suggesting that the 85-kd fragment is generated by an alternative initiation of translation or by proteolytic cleavage. Southern blotting detected no amplification of the Hgfr/Met gene in the 35 tumors examined, in contrast to our recent report of Hgfr/Met gene amplification in 7, 12-dimethylbenz(a)anthracene (DMBA)-induced rat sarcomas. The present data suggest that the locally aggressive and malignant properties of human mesenchymal tumors maybe related, in part, to high levels of full-length HGF receptors, and in some cases to the occurrence of N-terminally truncated HGF receptors, activated independently of HGF.

Blotting, Western↗