title: Abnormal rib number in childhood malignancy: implications for the scoliosis surgeon.
abstract: METHODS
  Retrospective review.
  
  
  OBJECTIVE
  To determine if rib anomalies are present in pediatric malignancies in the United States.
  
  
  BACKGROUND
  Scoliosis surgeons view radiographs of the entire spine, counting the number of ribs. A European study noted that rib anomalies were more common in certain malignancies. We wished to determine if this is also true in the United States. If so, the potential for screening, early detection of malignancy, and a better understanding of tumor biology is possible.
  
  
  METHODS
  A retrospective review of 218 children with malignancy and a control group of 200 children with polytrauma or suspected child abuse was performed. Chest radiographs were reviewed to determine the number of ribs, and the presence of rib anomalies. 24 ribs was considered normal, <24 or >24 was considered abnormal. P < 0.05 was considered significant.
  
  
  RESULTS
  The average age was 6.8 +/- 5.5 years and number of ribs was 23.8 +/- 0.6. Rib number was normal in 86.8%. There were significant differences between the malignancy and control groups in age (control, 5.7 +/- 5.1 years; malignancy, 7.8 +/- 5.7 years, P = 0.00007), rib number (control, 23.9 +/- 0.5; malignancy, 23.7 +/- 0.7, P = 0.001), and normal/abnormal rib counts (control, 92% normal; malignancy, 82% normal, P = 0.003). In the malignant group, 50% had a lymphoproliferative malignancy, 33% a solid tumor, and 17.0% a neural tumor. Neural malignancies had a higher incidence of rib abnormalities compared with lymphoproliferative or solid malignancies (P = 0.01). Relative to the control group, those with a neural and lymphoproliferative malignancy were 6.23 (95% CI, 2.7-14.5) and 2.0 (95% CI, 1.0-4.1) times more likely to have an abnormal rib count.
  
  
  CONCLUSIONS
  Homeobox genes, important in vertebral and rib sequencing, are abnormally expressed in many different malignancies. This association is a question of great interest. What is the potential for rib number being used as a predictor of childhood malignancy? Can these findings be expanded to adults? These questions require further research. The association noted in this study is interesting but should not yet be used to alarm parents regarding an increased risk of malignancy in their children.
authors.affiliation: James Whitcomb Riley Children's Hospital, Indianapolis, IN 46202, USA. rloder@iupui.edu
authors.forename: Randall T
authors.initials: RT
authors.lastname: Loder
authors.forename: Gretchen
authors.initials: G
authors.lastname: Huffman
authors.forename: Eugene
authors.initials: E
authors.lastname: Toney
authors.forename: L Daniel
authors.initials: LD
authors.lastname: Wurtz
authors.forename: Robert
authors.initials: R
authors.lastname: Fallon
mesh_terms: D000293:Adolescent; D001932:Brain Neoplasms / Q000453:epidemiology / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D005260:Female; D005801:Genes, Homeobox; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D009369:Neoplasms / Q000453:epidemiology* / Q000235:genetics; D009447:Neuroblastoma / Q000453:epidemiology / Q000235:genetics; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000453:epidemiology / Q000235:genetics; D015995:Prevalence; D012189:Retrospective Studies; D012272:Ribs / Q000002:abnormalities*; D012509:Sarcoma / Q000453:epidemiology / Q000235:genetics; D012512:Sarcoma, Ewing / Q000453:epidemiology / Q000235:genetics; D012600:Scoliosis / Q000453:epidemiology / Q000473:pathology / Q000601:surgery; D012983:Soft Tissue Neoplasms / Q000453:epidemiology / Q000235:genetics; D009396:Wilms Tumor / Q000453:epidemiology / Q000235:genetics