Malignant peripheral neuroectodermal tumor and its necessary distinction from Ewing's sarcoma: a report from the Kiel Pediatric Tumor Registry

Article Abstract:

The term sarcoma is, by convention, applied to cancers of mesenchymal origin such as those arising in muscle or bone. Ewing's sarcoma is a form of bone cancer; while it was originally thought to arise from bone marrow cells or from primitive mesenchyma, more recent data indicate that it may actually arise from neural cells, and therefore technically may not be a sarcoma at all. The appearance of Ewing's sarcoma under the microscope closely resembles that of another cancer, malignant peripheral neuroectodermal tumor (MPNT). Indeed, the two types of cancer are not always easy to distinguish, and definitive criteria for making this distinction do not yet exist. A study was conducted on surgical specimens from 117 cases of Ewing's sarcoma or MPNT, and specific antibodies were used to characterize some of the proteins in the cancerous cells. Two different diagnostic criteria were applied to the findings, an ''old'' classification system in which only one protein of neural origin was necessary for a diagnosis of MPNT, and a new classification system in which two different neural proteins were necessary for such a diagnosis. (Other pathological observations in addition to the antibody staining were also included among the diagnostic criteria.) Both classification systems uncovered cases that had not been accurately identified by the original pathological examination. Using the new classification, the original diagnosis was changed from MPNT to Ewing's sarcoma in 19 cases, and in eight cases the original diagnosis needed to be changed from Ewing's to MPNT. Using the new classification system, 81 cases were Ewing's sarcoma and 36 cases were MPNT. This distinction is of more than academic interest; the 7.5-year survival of the patients with Ewing's sarcoma was 60 percent, significantly better than the 45 percent survival of the MPNT patients over the same period. Furthermore, the precise findings of the antibody staining appeared to be related to the prognosis. MPNT cancers with the protein HNK-1, also called Leu 7, appeared to be more aggressive. In contrast, the presence of the protein S-100 seemed to be associated with less aggressive disease and a more favorable prognosis. (Consumer Summary produced by Reliance Medical Information, Inc.)

Ewing's sarcoma

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Synovial sarcoma in children and adolescents: a report from the Kiel Pediatric Tumor Registry

Article Abstract:

Synovial membranes are found near joints, tendons, and ligaments in areas where movement might create friction between tissues. Because of their close anatomical association, it is widely believed that synovial sarcomas arise from these tissues, but conclusive proof of this is still lacking. While there have been many scientific reports on the characteristics of synovial sarcomas, few of these reports have specifically dealt with the characteristics of these cancers in children. The authors review the cases of 35 patients under 18 years of age who developed synovial sarcomas. These childhood cases represent 71 percent of the total number of synovial sarcomas; synovial sarcomas represent 5.8 percent of all soft-tissue sarcomas recorded in this particular tumor registry. While it was possible to determine the histological structure of these cancers and the identity of the individual cell types by conventional light microscopy, the authors found that the use of specific antibodies to different cellular constituents, particularly the proteins of the cytoskeleton, made the task easier. In the course of using antibodies for specific cellular components, the researchers also observed some anomalous expression of antigens. Ten of 11 specimens examined revealed the presence of neuron-specific enolase, which, as its name implies, is generally considered to be found only in neurons. Likewise, 5 of 13 specimens examined were found to contain S-100, another protein considered to be specific for neural tissue. A 7-years survival rate of 72 percent was observed among the patients in the present study. Because these patients have not been followed-up for an extended period, the actual survival rate may turn out to be less than this. Synovial sarcoma is known to have late recurrences, which may develop as long as 20 years after the initial diagnosis. (Consumer Summary produced by Reliance Medical Information, Inc.)

Cancer in children, Childhood cancer

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Infantile desmoid-type fibromatosis: morphological features correlate with biological behaviour

Article Abstract:

Fibromatosis is the enlargement of the gums such that the teeth are covered with tissue. A number of subtypes of fibromatosis vary with regard to the age and sex of the patient, localization of disease, structural features and clinical behavior of the condition, including likelihood of recurrence. Desmoid tumors (a firm, rubbery-like tumor occurring in skeletal muscles) can occur in patients with fibromatosis. The structural features of the tissues of infantile desmoid-type fibromatosis lesions were examined to see if correlations could be made between various features and the behavior of the disease in 77 children and adolescents. The number of small blood vessels that are slit-like in appearance, indicating the degree of vascularization (amount of blood supply to the tumor) in the tissues, correlated with the tendency of the desmoid tumors to recur. Greater numbers of undifferentiated cells in the tissues also correlated with the tendency of the desmoid tumors to recur. No correlation was observed between the number of proliferating cells and the likelihood of recurrence. (Consumer Summary produced by Reliance Medical Information, Inc.)

Prognosis, Gingivitis, Gum diseases

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