title: Osteonecrosis of the jaws in patients treated with bisphosphonates - histomorphologic analysis in comparison with infected osteoradionecrosis.
abstract: BACKGROUND
  Patients treated with bisphosphonates because of bone metastases have been shown to develop osteonecrosis of the jaws. In the present study, we examined the histologic findings of these cases. As similarities between this disorder and infected osteoradionecrosis (IORN) are described, both lesions were compared.
  
  
  METHODS
  We investigated eight patients with bisphosphonate treatment and osteonecrosis (four female, four male; median age: 65.6 years; cancer: multiple myeloma in five patients, breast cancer in three patients; mandibular involvement in five patients, maxillar involvement in three cases), and 10 patients suffering from IORN (all male; median age: 61.3 years; cancer: squamous cell carcinoma in nine patients, adenoid cystic carcinoma in one patient; mandibular involvement in all cases). Multicentric and bilateral involvement was common in the bisphosphonate group. Histologically, the bone revealed diffuse and patchy areas of necrosis in the bisphosphonate group, while in IORN osteonecrosis was larger and not diffusely distributed.
  
  
  RESULTS
  In all cases, we found Actinomyces attached to the necrotic bone tissue. In five of eight bisphosphonates cases, and in six of 10 IORN cases, numerous osteoclasts could be detected close to vital bone exhibiting signs of bone resorption. Pseudoepitheliomatous hyperplasia (PH) was revealed in five of eight bisphosphonate patients, and in seven of 10 IORN patients.
  
  
  CONCLUSIONS
  We conclude that Actinomyces is involved in the chronic, non-healing inflammatory processes as a characteristic feature of both diseases. Together with the associated presence of increased osteoclast numbers, we suggest that both factors may be involved in osteolytic mechanisms.
authors.affiliation: Institute of Pathology, Johannes Gutenberg University, Mainz, Germany. torstenhansen@gmx.de
authors.forename: Torsten
authors.initials: T
authors.lastname: Hansen
authors.forename: Martin
authors.initials: M
authors.lastname: Kunkel
authors.forename: Achim
authors.initials: A
authors.lastname: Weber
authors.forename: C
authors.initials: C
authors.lastname: James Kirkpatrick
mesh_terms: D000190:Actinomyces / Q000302:isolation & purification; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000009:adverse effects; D050071:Bone Density Conservation Agents / Q000009:adverse effects; D001859:Bone Neoplasms / Q000188:drug therapy* / Q000556:secondary; D003528:Carcinoma, Adenoid Cystic / Q000188:drug therapy / Q000556:secondary; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000556:secondary; D004164:Diphosphonates / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007571:Jaw Diseases / Q000139:chemically induced / Q000382:microbiology / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D010020:Osteonecrosis / Q000139:chemically induced / Q000382:microbiology / Q000473:pathology*; D010025:Osteoradionecrosis / Q000382:microbiology / Q000473:pathology*
chemical_list: D000970:Antineoplastic Agents; D050071:Bone Density Conservation Agents; D004164:Diphosphonates