title: Hypertrophic osteoarthropathy: a palindrome with a pathogenic connotation.
abstract: OBJECTIVE
  The review seeks to update advances on the pathogenesis of hypertrophic osteoarthropathy, describe a previously unrecognized palindrome that occurs in hypertrophic osteoarthropathy and that may have pathogenic implications, and review the role of bisphosphonates in the treatment of this condition.
  
  
  RESULTS
  Some patients with primary hypertrophic osteoarthropathy display an interesting palindrome. Many years after the onset of the osteoarthropathy, they develop diseases that in other circumstances are known to generate secondary hypertrophic osteoarthropathy. This palindrome has been reported in cases of patent ductus arteriosus, Crohn's disease and myelofibrosis. Additionally, primary hypertrophic osteoarthropathy and POEMS syndrome share important clinical features. The many diseases associated with hypertrophic osteoarthropathy have in common abnormal production of vascular endothelial growth factor. This cytokine has been proposed to play a major role in the pathogenesis of Crohn's disease, myelofibrosis and POEMS syndrome. A controlled study showed that vascular endothelial growth factor is abnormally expressed in cases of hypertrophic osteoarthropathy. The biologic effects of vascular endothelial growth factor may explain hypertrophic osteoarthropathy histological features. Several isolated reports suggest that pamidronate is effective in relieving painful osteoarthropathy.
  
  
  CONCLUSIONS
  Hypertrophic osteoarthropathy is a palindromic syndrome. Anomalous vascular endothelial growth factor expression may explain this phenomenon. Bisphosphonates may have a role in the symptomatic treatment of hypertrophic osteoarthropathy.
authors.affiliation: Rheumatology Department, National Institute of Cardiology, Mexico. mmlavin@infosel.net.mx
authors.forename: Manuel
authors.initials: M
authors.lastname: Martinez-Lavin
authors.forename: Angélica
authors.initials: A
authors.lastname: Vargas
authors.forename: Miguel
authors.initials: M
authors.lastname: Rivera-Viñas
mesh_terms: D050071:Bone Density Conservation Agents / Q000627:therapeutic use; D003424:Crohn Disease / Q000150:complications; D004164:Diphosphonates / Q000627:therapeutic use; D004374:Ductus Arteriosus, Patent / Q000150:complications; D006801:Humans; D010004:Osteoarthropathy, Primary Hypertrophic / Q000150:complications / Q000503:physiopathology; D010005:Osteoarthropathy, Secondary Hypertrophic / Q000150:complications / Q000503:physiopathology; D016878:POEMS Syndrome / Q000150:complications; D000077268:Pamidronate; D055728:Primary Myelofibrosis / Q000150:complications; D042461:Vascular Endothelial Growth Factor A
chemical_list: D050071:Bone Density Conservation Agents; D004164:Diphosphonates; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D000077268:Pamidronate