title: Undifferentiated sarcomas of children: pathology and clinical behavior--an Intergroup Rhabdomyosarcoma study.
abstract: Undifferentiated soft tissue sarcoma (UND-STS) is the most poorly defined tumor eligible for intergroup Rhabdomyosarcoma Studies (IRS). Recent IRS UND-STS experience was reviewed to assess the histologic characteristics and clinical behavior of undifferentiated sarcomas. Of the 1,527 patients entered on IRS-III and IRS pilot-IV, 96 had tumors classified by the IRS Pathology Committee as UND-STS. Of these, 52 had adequate histologic material for this study. After application of immunohistochemistry, 18 tumors were reclassified, mostly as embryonal rhabdomyosarcomas (RMS), primitive neuroectodermal tumors, and intraabdominal desmoplastic small found cell tumors. The remaining 34 UND-STS had a diffuse hypercellular histologic pattern made up of sheets of medium-sized cells. The tumor cells had a minimal to moderate amount of cytoplasm and a variable nuclear morphology, predominately vesicular with finely granular chromatin. Except for reactivity with antibodies against vimentin, most tumors had a negative immunohistochemical profile. The 5 year Kaplan-Meier survival estimate for patients with non-metastatic disease was 72%, a significant improvement when contrasted with patients diagnosed to have UND-STS in IRS-I and IRS-II.
authors.affiliation: Department of Pathology, St. Christopher's Hospital for Children, Philadelphia, Pennsylvania, USA.
authors.forename: B R
authors.initials: BR
authors.lastname: Pawel
authors.forename: A B
authors.initials: AB
authors.lastname: Hamoudi
authors.forename: L
authors.initials: L
authors.lastname: Asmar
authors.forename: W A
authors.initials: WA
authors.lastname: Newton
authors.forename: F B
authors.initials: FB
authors.lastname: Ruymann
authors.forename: S J
authors.initials: SJ
authors.lastname: Qualman
authors.forename: B L
authors.initials: BL
authors.lastname: Webber
authors.forename: H M
authors.initials: HM
authors.lastname: Maurer
mesh_terms: D000293:Adolescent; D000328:Adult; D002467:Cell Nucleus / Q000648:ultrastructure; D002648:Child; D002675:Child, Preschool; D002843:Chromatin / Q000648:ultrastructure; D003593:Cytoplasm / Q000648:ultrastructure; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009367:Neoplasm Staging; D018242:Neuroectodermal Tumors, Primitive / Q000473:pathology; D010865:Pilot Projects; D012042:Registries; D018233:Rhabdomyosarcoma, Embryonal / Q000473:pathology; D012509:Sarcoma / Q000145:classification / Q000473:pathology* / Q000556:secondary; D018228:Sarcoma, Small Cell / Q000473:pathology; D015996:Survival Rate; D014746:Vimentin / Q000032:analysis
chemical_list: D002843:Chromatin; D014746:Vimentin