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PubMed1998

[A clinicopathological analysis of primitive neuroectodermal tumors of the CNS].

OBJECTIVE: To investigate the difference between cerebellar medulloblastoma (MB) and primary cerebral small cell tumor in histogenesis, morphologic features and biological behavior. METHODS: 210 cases of MB and 9 cases of small cell tumor of cerebrum were observed with histologic and immunohistochemical techniques. RESULTS: Both tumors were composed of primitive cells with focal evidence of glial and/or neuronal differentiation. In 63.2% of MB and five-eighths of small cell tumor of cerebrum coexpressed GFAP and Syn. Both types of tumors were highly malignant. The overall 1 year survival rates were 34.63% and 25.65% respectively. The survival rate was lower for patients with high proliferative index, with necrosis or without receiving radiation therapy. CONCLUSION: MB is similar to other small cell tumors of CNS in morphological features, specific marker expression and biological behavior. These tumors can be classified as primitive neuro-ectodermal tumors (PNET).

Adolescent↗
PubMedDate not supplied

Immunocytochemical detection of the homeobox B3, B4, and C6 gene products in childhood medulloblastomas/primitive neuroectodermal tumors.

The homeobox was originally described as a conserved DNA motif of about 180 base pairs. The protein domain encoded by the homeobox, the homeodomain, is thus about 60 amino acids long. The homeodomain is a DNA-binding domain, and many homeobox genes have now been shown to bind to DNA and regulate the transcription of other genes. Thus homeodomain proteins are basically transcription factors, most of which play a role in development. The homeobox genes seem to represent another class of oncofetal antigens involved in both normal development and carcinogenesis, as well as tumor progression. It has been shown that HOX-B3 and HOX-B4 are preferentially expressed in primitive CD34+, lineage-committed hematopoietic stem cells (HSCs) in human bone marrow. HOX-B3 overexpression in HSCs causes defective lymphoid development and progressive myeloproliferation, while HOX-B4 leads to selective expansion of HSCs without altering their differentiation. The HOX-C6 gene product leads to cell differentiation in neuroblastomas, while also being associated with the neoplastically transformed mammary cell phenotype and progression in primary cutaneous lymphomas. The expression pattern of these three homeobox gene products (HOX-B3, HOX-B4, and HOX-C6) was examined immunocytochemically in childhood MEDs/PNETs employing an indirect alkaline phosphatase conjugated technique on formalin-fixed, paraffin-embedded tissue sections. Strong staining intensity (A, B) of HOX-B3 and HOX-B4 was registered in all MEDs/PNETs, with immunoreactivity in between 50% and 90% (+3), but usually over 90% (+4) of the tumor cells. HOX-C6 was detected at medium intensity (mostly B) in 50% to 90% (+3) of the MED/PNET cells. This report is the first to describe the expression of these three homeobox gene products in MEDs/PNETs, and provides further evidence for the role of these proteins in the progression of human malignancies. The value of these genes and proteins in the early diagnosis and possible treatment of various human neoplasms, including childhood brain tumors, should be assessed in further immunocytochemical and molecular biological experiments.

Adolescent↗
PubMed1997

Melanogenic neuroectodermal tumor of the retina (primary malignant melanoma of the retina).

A 35-month-old girl with leukocoria was clinically diagnosed with unilateral sporadic retinoblastoma. Macroscopic examination of her enucleated eye disclosed a white retinal tumor that appeared to be a retinoblastoma. Histopathologic examination, however, revealed that the tumor was composed of poorly differentiated neuroblastic cells, larger spindle-shaped cells, and anaplastic epithelioid cells, which is inconsistent with retinoblastoma. Immunohistochemical testing disclosed that the tumor cells were immunoreactive for melanoma-specific antigen HMB-45, while electron microscopy showed premelanosomes in the tumor cells, both of which are consistent with melanogenesis. To our knowledge, such an ocular tumor has not been reported previously.

Antigens, Neoplasm↗
PubMed1995

EWS-FLI-1 and EWS-ERG chimeric mRNAs in Ewing's sarcoma and primitive neuroectodermal tumor.

The t(11;22)(q24;q12) and t(21;22)(q22;q12) are specific chromosomal translocations found in the Ewing family of tumors including ES, PNET and Askin tumors. In these translocations, the amino-terminal portion of the EWS gene located in 22q12 fuses to the carboxyl-terminal portion of the FLI-1 gene located in 11q24 or the ERG gene located in 21q22, which belong to the ets oncogene superfamily of transcription activators. We investigated the chimeric mRNAs of 15 ESs (7 cell lines and 8 tumor samples) and 7 PNETs (3 cell lines and 4 tumor samples) using the RT-PCR method and sequencing. We detected 2 types of EWS-ERG chimeric mRNA in 2 ES cell lines and 1 PNET tumor sample in addition to 4 types of EWS-FLI-1 chimeric mRNA in 11 ESs (4 cell lines and 7 tumor samples) and 4 PNETs (2 cell lines and 2 tumor samples). There seemed to be no association between the type of chimeric mRNA and clinical features such as sex, age, primary site and histopathology of the patients. All of the chimeric mRNAs are generated from in-frame junctions and are thought to encode fusion proteins that may be the molecular mechanism involved in the Ewing family of tumors.

Adolescent↗
PubMed2006

Primary primitive neuroectodermal tumor of the kidney: a case report.

There are nearly 50 PNET cases in the literature with primary renal localization. The mean age for renal PNET is 28 but it can be seen in a wide range between 4 and 69 years. In this atypical localization PNET may be mistaken with a variety of small round cell tumors, particularly with blastema predominant Wilms' tumor and due to its distinctive prognostic and therapeutic features differential diagnosis is very important. Immunohistochemical studies are useful in discriminating PNET from other renal small round cell tumors. Renal PNETs tend to metastasize at early stages and they have a high rate of recurrence. Our case is a 45-year-old male presented with left flank pain and hematuria. In computerized tomography a mass in left kidney was observed and nephrectomy was performed. Histopathologic examination revealed a small round cell tumor with rosettes and pseudorosettes. Immunohistochemically the lesion was diffuse strong positive with CD99 and NSE, negative with LCA, pancytokeratin, vimentin, desmin, smooth muscle actin, chromogranine A and S-100. At the time of diagnosis the pathologic stage of the tumor was T1aN0Mx. The patient did not take any further therapy and in 1-year follow-up no local recurrence or distant metastasize occurred.

Disease-Free Survival↗
PubMed1993

[Pathology and clinical aspects of peripheral neuroectodermal tumors].

A 36-year-old man developed progressive pain in the left thorax radiating to the shoulder, associated with weight loss as well as axillary and supraclavicular lymph-node swellings, and a left Horner's syndrome. The radiological diagnosis was Pancoast tumour. Computed tomography of the thorax revealed that the tumour had almost completely infiltrated the left lung and hilus. Sonography demonstrated metastases in the liver and retroperitoneum. Histological examination of an excised axillary lymph-node metastasis showed an undifferentiated small-cell tumour. Immunohistochemical tests revealed expression of protein S 100 and neurofilamental proteins, i.e. evidence of a peripheral malignant neuroectodermal tumour. The tumour also expressed vimentin. Treatment consisted of two chemotherapy cycles according to the EVAIA scheme (daily three times 235 mg etoposide, 2 mg vincristine, three times 0.8 mg actinomycin D, three times 3.2 g ifosfamide, three times 30 mg doxorubicin, and three times 12 mg dexamethasone), without any effect on the rapid progression of the disease. He died 17 weeks after the diagnosis had been made.

Adult↗
PubMed1998

[Peripheral neuroectodermal tumors of the chest wall. Description of a case].

The authors discuss a case of malignant small round cell tumor of the thoracopulmonary region (Askin tumor) in which the initial pathological diagnosis was "sarcoma". Only a review of the histological specimens and the clinical features and evolution revealed the correct diagnosis of "Askin tumor". A 15 year old girl with fever, dyspnoea, cough underwent thoracentesis, which revealed hemothorax. At surgery, a large mass not involving the lung, with pleural thickening, was found in the left hemithorax and excised, without rib resection. No metastasis was observed at that time. Histological findings revealed features of malignant small round cell tumors, with occasional pseudo-rosettes. Chemotherapy was performed. 16 months after clinical presentation the girl died with abdomino-thoracic metastatic disease.

Adolescent↗
PubMed1998

Ewing's sarcoma and peripheral primitive neuroectodermal tumors after their genetic union.

The Ewing family of tumors has been defined by the presence of an EWS-ets gene rearrangement. Using molecular techniques for the visualization of this aberration, several tumors of unusual location and histology were recently identified and added to this group. Increasing experimental data suggest that EWS-ets fusions act as transforming transcription factors. Subtractive screening of transgenic fibroblasts has led to the identification of potential targets. The authentic cellular context for these aberrant gene products is still unknown and may be diverse, however. Clinical heterogeneity has stimulated a search for genetic factors that may relate to treatment response. The effect of the EWS-ets fusion transcript structure on localized disease has been recently confirmed and frequent p16 tumor suppressor alterations have been described. The presence of metastases at diagnosis as the major predictor of outcome has been assessed on a submicroscopic level by reverse transcriptase-polymerase chain reaction. Problems arising from these studies are discussed, although the biological basis for variable disease extension remains obscure.

Heterogeneous-Nuclear Ribonucleoproteins↗
PubMed1998

Survival of very young children with medulloblastoma (primitive neuroectodermal tumor of the posterior fossa) treated with craniospinal irradiation.

PURPOSE: Very young children with medulloblastoma are considered to have a worse prognosis than older children. As radiotherapy remains an important part of the treatment, the adverse prognosis could be due to inadequate radiation treatment rather than biological factors. We analyzed the published literature to examine the impact of radiotherapy on survival in this group. METHODS AND MATERIALS: A Medline search was performed and we reviewed studies of treatment of medulloblastoma where radiotherapy was delivered using megavoltage equipment and the minimum follow-up allowed the calculation of 5-year survival rates. RESULTS: Thirty-nine studies were published between 1979 and 1996 with a treatment including craniospinal irradiation and boost to the posterior fossa. Eleven studies comprising 1366 patients analyzed survival by age at diagnosis. Eight of 11 studies showed a worse 5-year survival for the younger patient group which reached statistical significance in two. There is also a suggestion of a higher proportion of children with metastatic disease at presentation in the very young age group. The usual policy in younger children was to give a lower dose of radiotherapy to the craniospinal axis (CSA) and posterior fossa (PF) with reduction of dose in the range of 15 to 25% compared to standard treatment. As dose reduction to the posterior fossa is associated with worse survival and local recurrence is the predominant site of failure, the major determinant of worse survival in very young children with medulloblastoma may be suboptimal radiotherapy. Protocols including postoperative chemotherapy with delayed, omitted, or only local tumor irradiation do not reach survival rates of protocols with standard radiotherapy, also suggesting a continued importance for irradiation. CONCLUSION: Very young children with medulloblastoma have a worse prognosis than older children. Inadequate radiation dose and technique to the primary tumor region may be a major contributing factor. Current chemotherapeutic regimes alone are not sufficient to compensate for reduced radiation doses and volumes.

Age Factors↗