title: Unusual leukemic presentation of rhabdomyosarcoma: report of two cases with immunological, ultrastructural and cytogenetical studies.
abstract: BACKGROUND
  Bone marrow infiltration occurs rarely at presentation of rhabdomyosarcoma (RMS) or other childhood solid tumors. This possibility leads to misdiagnosis of leukemia and incorrect therapies might be administered.
  
  
  METHODS
  We report two patients presenting with diffuse bone marrows involvement by neoplastic cells. Initial studies were not consistent with a diagnosis of leukemia and the cases were further studied extensively by indirect immunofluorescence, immunocytochemistry, electron microscopy and cytogenetics.
  
  
  RESULTS
  In both cases blast cells were large, poorly differentiated, with immunological reactivity to the anti-desmin antibody. Ultrastructural findings of muscular features and chromosomal translocation t(2;13) (q37;q14) further confirmed the diagnosis of rhabdomyosarcoma of the alveolar subtype. This was then confirmed histologically in one patient.
  
  
  CONCLUSIONS
  This study stresses the utility of analyzing cases of morphologically undifferentiated marrow blast cells by various techniques, as well as investigating for different types of both hematological and solid neoplasms.
authors.affiliation: Dipartimento di Pediatria, Università di Padova, Italy.
authors.forename: M C
authors.initials: MC
authors.lastname: Putti
authors.forename: A
authors.initials: A
authors.lastname: Montaldi
authors.forename: A
authors.initials: A
authors.lastname: D'Emilio
authors.forename: L
authors.initials: L
authors.lastname: Sainati
authors.forename: C
authors.initials: C
authors.lastname: Milanesi
authors.forename: M
authors.initials: M
authors.lastname: Stella
authors.forename: L
authors.initials: L
authors.lastname: Zanesco
authors.forename: G
authors.initials: G
authors.lastname: Basso
mesh_terms: D000293:Adolescent; D015703:Antigens, CD / Q000032:analysis; D014408:Biomarkers, Tumor / Q000032:analysis; D001856:Bone Marrow Examination; D002882:Chromosomes, Human, Pair 13 / Q000648:ultrastructure; D002889:Chromosomes, Human, Pair 2 / Q000648:ultrastructure; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007938:Leukemia / Q000175:diagnosis*; D015470:Leukemia, Myeloid, Acute / Q000175:diagnosis; D008297:Male; D008479:Mediastinal Neoplasms / Q000737:chemistry / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D009124:Muscle Proteins / Q000032:analysis; D009363:Neoplasm Proteins / Q000032:analysis; D012208:Rhabdomyosarcoma / Q000737:chemistry / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D013899:Thoracic Neoplasms / Q000737:chemistry / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D014178:Translocation, Genetic
chemical_list: D015703:Antigens, CD; D014408:Biomarkers, Tumor; D009124:Muscle Proteins; D009363:Neoplasm Proteins