ORBITAL RHABDOMYOSARCOMAS AND RELATED TUMORS IN CHILDHOOD - RELATIONSHIP OF MORPHOLOGY TO PROGNOSIS - AN INTERGROUP RHABDOMYOSARCOMA STUDY

Children and adolescents who develop rhabdomyosarcoma (RMS) and relate d sarcomas in the orbit and treated on Intergroup Rhabdomyosarcoma pro tocols have had an extremely high cure rare. This study evaluates the possible relationship between their tumor morphologic subtypes and thi s high cure rate. The histology oi tumors was re-reviewed from 229 of the 264 patients with tumors of the orbit, conjunctiva, and eyelids tr eated on Intergroup Rhabdomyosarcoma Studies (IRS) I, II, III, and IV pilot protocols, and followed through July, 1992. Immunohistochemistry was applied in selected cases. Clinical correlations were done on all 264 cases including both the re-reviewed cases and those reviewed onl y by the IRS Pathology committee. The 5-year survival rate of 24 child ren with alveolar RMS was 74% (p < .001). Ail five infants diagnosed t o have an alveolar RMS died before the age oi one. Two hundred and twe nty-one patients (84%) had embryonal RMS. About three-fourths of the r e-reviewed embryonal RMS tumors showed only minimal rhabdomyoblastic d ifferentiation. Thirty-one had a spindle cell RMS, two were anaplastic variants. The 5-year survival rate for patients with embryonal RMS su btypes combined was 94%, and 97% for the 144 patients with poorly diff erentiated embryonal RMS. In contrast, 190 of 432 IRS II patients trea ted for poorly differentiated embryonal RMS located in extraocular sit es had a 66% survival estimate. (C) 1997 Wiley-Liss, Inc.