Massive Bone Marrow Infiltration by Disseminated Alveolar Rhabdomyosarcoma Mimicking Acute Leukemia

RMS is a malignant tumor of soft tissues affecting primarily children and adolescents. Around 6% to 23% RMS patients present bone marrow infiltration but leukemia-like involvement is very rare; in these patients cytomorphology on bone marrow smears can lead to misdiagnosis. Differential diagnosis with alveolar RMS should be kept in mind in every pediatric patient presenting with a marked bone marrow involvement in the absence of typical lymphoproliferative findings.