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Emergency management of severe right ventricular inflow obstruction secondary to a metastatic cardiac tumor.

We report the case of a 21-year-old female with previous history of primitive neuroectodermal tumor of the anterior abdominal wall who developed severe manifestations of right heart failure due to a mass obliterating the right ventricular cavity. She underwent emergent resection of the mass with histopathologic confirmation of metastatic neuroectodermal tumor. To the best of our knowledge, this is the first case of emergent surgical excision of a metastatic cardiac tumor of primitive neuroectodermal origin.

Abdominal Neoplasms↗

Primary intracerebral malignant fibrous histiocytoma: immunohistochemical findings and etiopathogenetic considerations.

We report a case of malignant fibrous histiocytoma (MFH) arising as a second malignancy in a 13-year-old girl with a previous primitive neuroectodermal tumor of the cerebellum (medulloblastoma). The earlier tumor had been resected and treated with chemotherapy. Because of the age of the patient, no radiation therapy was used. The second neoplasm (an MFH), which presented almost 12 years later, was located within the left frontal region and had discrete meningeal attachment. Histologically, it showed the characteristic storiform pattern and pleomorphism of an MFH and displayed characteristic immunohistochemical reactivity. Careful clinical and radiologic investigation failed to reveal any other neoplasm in the body. This case is unique in that the MFH occurred in a young child after an earlier primary primitive neuroectodermal tumor, although at a distant site, and, importantly, without prior radiation therapy. In this report, we briefly review the literature with an emphasis on immunohistochemistry and histogenesis, raising the possibility that the MFH was induced by chemotherapy.

Adolescent↗

Malignant peripheral primitive neuroectodermal tumor-peripheral neuroepithelioma of the head and neck: a clinicopathologic study of five cases and review of the literature.

BACKGROUND: The term primitive neuroectodermal tumor (PNET) encompasses a number of neoplasms of common neuroectodermal origin, but of variable clinical, histopathologic, ultrastructural, and molecular characteristics. Here, we focus on one particular member of the PNET family, the malignant peripheral PNET (pPNET) or peripheral neuroepithelioma of head and neck. METHODS: Five patients diagnosed with malignant pPNET-peripheral neuroepithelioma of head and neck were included in the study. All existing literature was reviewed. RESULTS: The diagnosis of malignant pPNET-peripheral neuroepithelioma of the head and neck was confirmed in all five cases. All patients are alive after treatment with a combination of therapeutic modalities; only one patient had metastatic disease develop. A literature review revealed another 38 reported cases. CONCLUSIONS: Malignant pPNET-peripheral neuroepithelioma should be included in the differential diagnosis of small, round, blue cell tumors of head and neck. A combination of multiple diagnostic modalities is essential for correct diagnosis, and multimodality treatment offers the best outcome.

12E7 Antigen↗

A case of undifferentiated glioma in a 70-year-old woman.

The present case involved a 70-year-old woman who was diagnosed with a right cerebral hemorrhage. Excisional surgery of the hematoma was performed. Grossly, a whitish, solid tumor (1 x 1 x 0.8 cm in size) was recognized in the hematoma. Histologically, the tumor was composed of large, polygonal cells and small undifferentiated cells in a jumbled architectural arrangement with a cartilage component. The large, polygonal cell component was conspicuous and somewhat rhabdoid in appearance and appeared to be an astrocytic tumor showing glial differentiation. The small, undifferentiated cell component resembled tumor cells of a primitive neuroectodermal tumor (PNET). Clinical follow-up of the patient for 2 months after the first operation revealed recurrence with rapid growth. A second operation was performed, but the patient died 8 months after the first operation (2 months after the second). Immunohistochemically, the tumor cells suggesting glial differentiation were positive for glial fibrillary acidic protein (GFAP), S-100, neuron-specific enolase (NSE), and vimentin. PNET-like components in the primary tumor were positive for NSE, GFAP, and S-100, and weakly positive for vimentin and synaptophysin. Each tumor cell was negative for epithelial membrane antigen (EMA), keratin, desmin, actin, myoglobin, neurofilament (NF), and MIC2 protein. The recurrent tumor revealed predominantly PNET-like components; however, only a few tumor cells were positive for GFAP. This appearance suggested that this brain tumor might originate from a common multipotential stem cell. Considering its histopathological and immunohistochemical characteristics, the primary tumor was finally regarded as an undifferentiated glioma with dedifferentiation of the glial component in the recurrent tumor.

Aged↗

Primitive neuroectodermal kidney tumor: 2 case reports and review of the literature.

Peripheral neuroectodermal tumors are uncommon cancers arising from outside the central nervous system. The urinary system is rarely involved. The differentiation of these tumors from other small cell cancer and neuroblastoma is based on immunohistochemical differences. We report 2 cases of such tumors arising from the renal parenchyma. Tumor behavior and treatment modalities are discussed.

Adult↗

Epigenetic repression of RASSF1A but not CASP8 in supratentorial PNET (sPNET) and atypical teratoid/rhabdoid tumors (AT/RT) of childhood.

Supratentorial primitive neuroectodermal tumors (sPNET) and atypical teratoid/rhabdoid tumors (AT/RT) of the CNS represent a biological and clinical enigma, despite advances in both molecular techniques and clinical management for these two rare embryonal brain tumors of childhood. Epigenetic changes hold great potential as possible disease mechanisms and may be manipulated therapeutically. We thus studied aberrant methylation of the genes RASSF1A and CASP8 and its consequence on expression in cell lines and primary tumors using a combination of semiquantitative methylation specific PCR (MSP), bisulfite sequencing and RT-PCR. In all, 17 samples of autopsy-derived normal appearing brain served as controls. Opposed to control tissues 19/24 sPNET and 4/6 AT/RT demonstrated aberrant methylation for the RASSF1A promoter region. Treatment of cell lines using 5-Aza-2'-deoxycytidine (5AZA) alone or in combination with trichostatin A (TSA) succeeded in re-establishing expression of RASSF1A in cell lines derived from a renal rhabdoid, an AT/RT and a medulloblastoma. A 5' CpG-rich region of CASP8 was methylated in normal tissues and in tumors. However, CASP8 showed inconsistent expression patterns in normal and tumor tissues. Our results indicate that aberrant methylation of the RASSF1A promoter region may be of importance in the origin and progression of sPNET and AT/RT while the analysed 5'-CpG rich region of the CASP8 gene does not seem to play an important role in these tumors. Further studies of epigenetic changes in these rare tumors are warranted as their biology remains obscure and treatment efforts have been rather unsuccessfull.

Adolescent↗

Molecular heterogeneity in medulloblastoma with implications for differing tumor biology.

Medulloblastomas and related primitive neuroectodermal tumors are the second most common malignant tumors of childhood. In spite of improvements in cancer therapy, these tumors are still associated with significant morbidity and mortality. Although these tumors share similar histologic features, recent molecular studies suggest that they could represent a genetically mixed group of tumors. The genetic events that might play a role in the biology of these tumors also could allow a molecular subtyping of medulloblastomas. Such molecular subtyping of medulloblastomas could allow for the use of newer therapeutic techniques, such as gene therapy, for selective targeting of critical genetic events in subsets of medulloblastomas. It is becoming increasingly clear that in medulloblastomas, the morphologic similarity of "small blue" cells does not imply similar or shared molecular characteristics, with implications for differing tumor biology.

Cell Cycle↗

Immunohistochemical evaluation of small round cell tumors of childhood.

OBJECTIVE: This study was done to evaluate the pediatric undifferentiated small round cell tumors with immunohistochemical staining. SETTING: The present study included consecutive cases of small round cell tumors which were diagnosed in children (< 15 years) in the section of Histopathology at the Aga Khan University Hospital, Karachi during the period of two years. METHODS: The group of undifferentiated small round cell tumors were evaluated immunohistochemically by using a panel of antibodies on sections from routinely processed, formalin fixed, paraffin embedded tissue blocks. RESULTS: The category of undifferentiated small round cell tumors included rhabdomyosarcoma (23.2%), primitive neuroectodermal tumor (17.9%), non-Hodgkin's lymphoma (16.1%), neuroblastoma (14.2%), Ewing's sarcoma (10.7%) in order of frequency. Osteosarcoma (Small cell variant), retinoblastoma and medulloblastoma comprised 1.8% each. In seven cases (12.5%), the immunohistochemical analysis was inconclusive. CONCLUSION: Immunohistochemistry is a very valuable diagnostic tool which helps in distinguishing the undifferentiated tumors especially small round cell tumors. The immunohistochemical staining needs to be performed routinely for undifferentiated tumors in diagnostic histopathology.

Adolescent↗

[Primitive renal neuroectodermal tumor (PNET). Apropos of a case].

Renal primary neuroectodermal tumours (PNET) are exceptional and belong to the vast group of peripheral malignant primary neuroectodermal tumours (MPNT), the best known forms of which are Ewing's sarcoma of bone and Askin's thoracopulmonary tumour. In the light of a case, the authors discuss the clinical features, course, treatment and pathological characteristics, particularly the value of immunohistochemistry and cytogenetics, which demonstrate a specific chromosomal abnormality, the t (11;22) (q24;q12) translocation.

Adolescent↗

Interphase cytogenetics for the detection of the t(11;22)(q24;q12) in small round cell tumors.

Among the small round cell tumors differential diagnosis is particularly difficult for their undifferentiated or primitive character. In this mixed group of tumors, only the primitive neuroectodermal tumors, which include Ewing's sarcoma (ES), show the unique and consistent feature of the (11;22)(q24;q12) translocation, which can therefore be considered a hallmark of these neoplasias. We analyzed four primitive neuroectodermal tumor cell lines, one osteosarcoma cell line, and 11 patients by fluorescent in situ hybridization with cosmid clones 23.2 and 5.8, bracketing the t(11;22) at 11q24. Metaphase spreads from tumor cell lines, and from biopsy specimens of three patients with ES were analyzed. In the remaining eight patients comprising five ES, two small cell osteosarcomas and one chronic osteomyelitis, only nuclei preparations were available for analysis. We detected the t(11;22) in interphase nuclei of the four primitive neuroectodermal tumor cell lines, of three patients in which the karyotype demonstrated the translocation and in five cases of ES in which cytogenetic analysis had not been possible. Two cases of small cell osteosarcoma and one chronic osteomyelitis were also analyzed and were both normal with respect to the t(11;22). By analyzing cell lines and small round cell tumor samples by fluorescent in situ hybridization, we established that interphase cytogenetics is a rapid alternative to chromosomal analysis for the detection of the t(11;22) and represents an invaluable tool for the differential diagnosis of small round cell tumors.

Adolescent↗

Trilateral retinoblastoma: insights into histogenesis and management.

Trilateral retinoblastoma (TRb) is a syndrome involving midline intracranial malignancies in children with the heritable form of retinoblastoma. All cases of TRb reported from 1971 to 1997 were reviewed. The histopathologic findings, clinical features, treatment modalities, and survival rates from 80 cases were evaluated. Histopathologic findings from intracranial malignancies demonstrated primitive neuroectodermal tumors in 61.5% of cases. Various degrees of neuronal or photoreceptor differentiation were seen in the other 38.5% of cases. Autopsy, histopathologic, and radiologic examinations did not show a more definitive site of origin of these intracranial tumors, although "pinealoblastoma" was often the diagnosis reported. These findings, together with analysis of the histopathologic similarities among human primitive neuroectodermal tumors, pinealoblastoma, retinoblastoma, and ependymoblastoma, suggest that TRb more likely arises from a germinal layer of predisposed primitive subependymal neuroblasts that are not necessarily destined for pineal or photoreceptor differentiation. Trilateral tumors have also been found in transgenic mice expressing the simian virus 40 T-antigen. Transgenic murine intracranial tumors are primitive neuroectodermal tumors arising from the subependymal layer. Transgenic mice with the murine interphotoreceptor cell binding protein promoter and simian virus 40 T-antigen also develop pineal tumors. Trilateral retinoblastoma is usually fatal, with an average survival time of 11.2 months. Therapies include radiation, systemic chemotherapy, intrathecal chemotherapy, and surgical resection/craniotomy in combination with radiation and/or chemotherapy. Survival may be prolonged with combination chemotherapy (24.6 months) and if neuroradiologic screening identifies TRb before symptoms are present (23.5 months). Recent success with platinum-based chemoreduction of intraocular retinoblastoma may indicate a similar role for platinum-based chemotherapy in the treatment of TRb. Routine central nervous system imaging should be considered in the management of TRb.

Animals↗

Maturation of a primitive neuroectodermal brain tumor? A case study with some remarks on the classification and nomenclature of 'primitive' CNS tumors.

A brain tumor in a 4-year-old child is described. The neoplasm was partly cystic and showed an a-typical multi-differentiated aspect. Microscopically the neoplasm had a clear-cut 'malignant' morphology. This tumor represents possibly a partly maturated primitive neuroectodermal brain tumor. The term PNET is briefly discussed in relation to the clinical implications.

Brain Neoplasms↗

Ewing's sarcoma and primitive neuroectodermal family of tumors.

Ewing's sarcoma (ES) initially was believed to be of perivascular endothelial origin. The Ewing's sarcoma family of tumors (EFT) includes ES of bone (ESB), extraosseous ES (EES), peripheral primitive neuroectodermal tumor of bone (pPNET), and malignant small-cell tumor of the thoracopulmonary region, or Askin's tumor, all of which are now known to be neoplasms of neuroectodermal origin. The degree of neuronal differentiation has been used for histopathologic subclassification of the EFT as classical ES (ESB or EES), which is characterized by minimal evidence of neural differentiation, and pPNET, which displays evidence of neural differentiation by standard microscopy, electron microscopy, or immunohistochemistry. Because the behavior, prognosis, and treatment appear to be similar for all subsets of EFT, this histopathologic subclassification may not be clinically significant, though some debate remains whether neural differentiation predicts for inferior outcome.

Bone Neoplasms↗

Askin tumors in children: a report of four cases.

Primary malignant tumors of the chest are rare in the pediatric age group. Askin tumor belongs to the peripheral primitive neuroectodermal tumor family, and typically involves the periosteum, soft tissue and extrapulmonary tissue of the thoracic wall. We report our ten years experience with four cases of this rare tumor.

Child↗