Atypical biological behavior of alveolar rhabdomyosarcoma in five patients

Five cases of alveolar rhabdomyosarcoma with atypical clinical features are reported. Three patients showed lymphadenophaty as the first clinical mani festation, mimicking a lymphoma or a non identified primary tumor with lymp h node metastases. One patient presented systemic neoplastic disease and tw o had the primary tumor in atypical locations, such as the mediastinum and retroperitoneum. All patients died and in four of them an autopsy was perfo rmed. The histological diagnosis was confirmed by immunohistochemical studi es on four cases. The alveolar rhabdomyosarcoma has a poor prognosis and ca n have a variable clinical presentation and morphology, simulating lymphoma s, leukemias and systemic metastatic disease with an unknown primary neopla sm, such as in the cases here in reported.