Dedifferentiated parosteal osteosarcoma of the maxilla: A case report and review of the literature

Hidetaka Miyashita, Kazunari Yoshida, Tomoya Soma, Kaori Kameyama, Aya Sasaki, Masanori Hisaoka, Masaki Yazawa, Hideo Morioka, Moe Takahashi, Taneaki Nakagawa, Hiromasa Kawana

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6 Citations (Scopus)


Background: Parosteal osteosarcomas are usually low-grade tumors, however, sometimes they transform to high-grade tumors, which is named dedifferentiation. This phenomenon has been reported in long bones. Recently, we encountered a patient with dedifferentiated parosteal osteosarcoma occurring in the maxilla. Here, we report a first case of dedifferentiated parosteal osteosarcoma of the head and neck region. Case presentation: A 45-year-old Japanese woman with a refractory bone lesion in the maxilla presented to our hospital. A biopsy showed atypical spindle cell proliferation involving dedifferentiated high-grade component, which was diagnosed as dedifferentiated parosteal osteosarcoma. Three cycles of neoadjuvant chemotherapy using ifosfamide and pirarubicin were performed followed by sub-total maxillectomy. Histopathological results showed that neoadjuvant chemotherapy was effective for high-grade component. The decision to perform adjuvant chemotherapy (cisplatin and pirarubicin) was made because distant metastasis has been reported, even in cases with dedifferentiated parosteal osteosarcoma in which complete necrosis of high-grade component was achieved due to neoadjuvant chemotherapy. There was no recurrence 15 months after surgery. Conclusions: Dedifferentiated parosteal osteosarcoma can occur in the head and neck region. Chemotherapy including anthracycline anticancer agent could be effective for high-grade component of dedifferentiated parosteal osteosarcoma.

Original languageEnglish
Article number235
JournalJournal of Medical Case Reports
Issue number1
Publication statusPublished - 2018 Aug 17


  • Case report
  • Chemotherapy
  • Dedifferentiated
  • Head and neck
  • Maxilla
  • Parosteal osteosarcoma

ASJC Scopus subject areas

  • Medicine(all)


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