Round Cell Tumors Of Childhood Research Articles

Correlative ultrastructure and immunocytochemistry in small round cell tumors of childhood

Conventional methods of pathologic evaluation of the undifferentiated solid tumors of childhood, often referred to as “small round cell tumors”, have been notoriously unreliable. Prior to the advent of effective therapy, this was of little consequence. Current treatment methods require precise categorization of these tumors, as tumor response shows wide variation, especially when inappropriate chemotherapeutic agents or radiation therapy are employed. The combination of transmission electron microscopy (TEM) and correlative immunocytochemistry (ICC) has proved to be a powerful tool in deriving precise diagnoses.The common small round cell tumors of childhood include sarcomas (especially undifferentiated rhabdomyosarcoma), lymphomas (especially lymphoblastic and large cell), neural tumors (neuroblastoma and a variety of apparently related neoplasms), and particularly Ewing's sarcoma, an enigmatic tumor of inapparent histogenesis with which all the above are compared. The treatment and prognosis of each of these groups is quite different, and we have attempted to reliably distinguish each from the other by ultrastructural and immunocytochemical criteria.

Significance of immunohistologic methods in the differential diagnosis of solid tumors in childhood

We have investigated 56 histologic and 13 cytologic specimens of malignant round cell tumors of childhood. The immunohistological detection of intermediate filament polypeptides, neuron specific enolase (NSE) as well as leukocyte common antigen (LCA) allows the histological classification of such tumors. Neuroblastomas demonstrate a positive reaction with antibodies to neurofilaments and NSE independent of differentiation. Rhabdomyosarcomas could be labeled by the desmin antibody, while Ewing sarcomas, malignant lymphomas as well as nonmuscular sarcomas only express vimentin. In nephroblastomas the intermediate filament specific antibodies reveal expression of keratin and vimentin in blastema cells, while tubules are only labeled by the keratin antibody. In undifferentiated nephroblastomas, which lack formation of tubules blastema cells are keratin negative and vimentin positive. Thus antibodies to intermediate filaments, LCA and NSE seem to be useful tools to distinguish the so called "round cell tumors" of childhood.

Cytogenetic characterization of selected small round cell tumors of childhood

Small, round, blue-cell tumors (SRCT), including rhabdomyosarcoma, Ewing's sarcoma of bone and soft tissue, mesenchymal chondrosarcoma, small cell osteosarcoma, hemangiopericytoma, neuroblastoma, peripheral neurectodermal tumor (peripheral neuroepithelioma of bone and soft tissue), and the malignant small cell tumor of the thoracopulmonary region described by Askin (Askin's tumor), are often difficult to distinguish by light microscopy. We have evaluated the cytogenetics of these tumors by studying 24 tumor explants in short-term culture and 22 tumor cell lines. In Ewing's sarcoma (a tumor of unknown histogenesis), and in peripheral neuroepithelioma and Askin's tumor (tumors with evidence of neural origin), we have observed an indistinguishable t(11;22) translocation.

Pan-leukocyte monoclonal antibody L3B12. Characterization and application to research and diagnostic problems.

In this report, the authors describe a murine anti-human monoclonal antibody, L3B12, which defines a pan-leukocyte cell surface antigen of approximately 180,000 m.w. Extensive screening against a variety of tissues indicates that L3B12 is sensitive and specific for leukocytes, related cells of bone marrow lineage, and their corresponding neoplasms. Unlike many lymphoid antigens that are not detectable following routine fixation and embedding, those recognized by L3B12 and related antibodies are variably preserved. L3B12 has proven useful in studying the antigen expression of normal leukocytic elements, lymphomas, and related disorders, and in enriching or depleting leukocytes from heterogeneous cell populations. From a diagnostic standpoint, L3B12 staining of tissue sections or cell suspensions is useful for distinguishing large cell lymphomas from undifferentiated carcinomas and in distinguishing lymphomas and leukemias from other small round cell tumors of childhood.