Neonatal rhabdomyosarcoma: the IRS experience.

Neonatal rhabdomyosarcoma is rare, and the characteristics and optimal therapy for patients with this condition have not been well described. Of 3,217 eligible patients entered in the Intergroup Rhabdomyosarcoma Study (IRS), 14 were less than 30 days old at the time of diagnosis. Among these patients, male gender, Caucasian race, caudal tumors, and embryonal/botryoid and undifferentiated histology predominate. Although half the neonates survived, neither histology, tumor size, nor type of surgery were predictive of outcome. The presence of necrosis and small round cell configuration coincides with a poor prognosis, regardless of histological diagnosis. Neonatal rhabdomyosarcoma of caudal origin has a favorable prognosis.