Congenital pseudarthrosis of the tibia: Analysis of the histology and the NF1 gene

Akio Sakamoto, Tatsuya Yoshida, Hidetaka Yamamoto, Yoshinao Oda, Masazumi Tsuneyoshi, Yukihide Iwamoto

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28 Citations (Scopus)


Background. Congenital pseudarthrosis of the tibia (CPT) is frequently, but not always, associated with neurofibromatosis type 1 (NF1). Double inactivation of the NF1 gene has been reported to be the pathogenesis of CPT in NF1 cases. Methods. We analyzed the loss of heterozygosity (LOH) of the NF1 gene in cases of CPT with NF1 to examine whether double inactivation was seen in the case. In addition to morphological analysis, immunoexpression of differentiation markers was examined. Results and discussion. The tibia tapered with the zone phenomenon from mature to immature bone with osteoblastic rimming, resembling osteofibrous dysplasia. Osteosclerotic bowed bone with a small number of osteoclasts suggested dysfunction of bone remodeling. Fibrous tissue at the site of pseudarthrosis was associated with the periosteum and demonstrated myofibroblastic differentiation accompanied by massive cartilage formation, suggesting some misdirection during the differentiation of periosteum to myofibroblasts or chondrocytes. LOH of the NF1 gene locus was not seen in fibrous tissue. This result suggests that CPT is not accompanied by double inactivation in every NF1 case.

Original languageEnglish
Pages (from-to)361-365
Number of pages5
JournalJournal of Orthopaedic Science
Issue number4
Publication statusPublished - Jul 2007

All Science Journal Classification (ASJC) codes

  • Surgery
  • Orthopedics and Sports Medicine


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