title: Soft tissue recurrent ameloblastomas also show some malignant features: A clinicopathological study of a 15-year database.
abstract: BACKGROUND
  To investigate the clinicopathological features of six cases of soft tissue recurrent ameloblastoma and explore the role of increased aggressive biological behavior in the recurrences and treatment of this type of ameloblastomas.
  
  
  METHODS
  In this study, we retrospectively reviewed recurrent ameloblastomas during a 15-year period; six cases were diagnosed as soft tissue recurrent ameloblastoma. The clinical, radiographic, cytological and immunohistochemical records of these six cases were investigated and analyzed.
  
  
  RESULTS
  All the six soft tissue recurrent ameloblastomas occurred after radical bone resection, and were located in the adjacent soft tissues around the osteotomy regions. In Case 4, the patient developed pulmonary metastasis, extensive skull-base infiltration and cytological malignancy after multiple recurrences and malignant transformation was diagnosed. In the other five cases, although there were no cytological signs are sufficient to justify an ameloblastoma as malignant, some malignant features were observed. In Case 1, the tumor showed moderate atypical hyperplasia and the Ki-67 staining percentage was 40% positive, which are strongly suggestive of potential malignance. In Case 5, the patient developed a second soft tissue recurrence in the parapharyngeal region and later died of tumor-related complications. All the remaining three patients showed cytology atypia of varying degrees and high expression of PCNA or Ki-67, which confirmed active cell proliferation.
  
  
  CONCLUSIONS
  Increased aggressiveness is an important factor of soft tissue recurrence. An intraoperative rapid pathological examination and more radical treatment are suggested for these cases.
authors: Department of Dentomaxillofacial Radiology, Affiliated Stomatology Hospital of Medical School, Nanjing University, Zhong Yang Road 30, Nanjing, China tiemeiwang106@163.com.
authors: Zitong
authors: Z
authors: Lin
authors: Guowen
authors: G
authors: Sun
authors: Tiemei
authors: T
authors: Wang
authors: Qingang
authors: Q
authors: Hu
authors: Fei
authors: F
authors: Chen
authors: Shanhui
authors: S
authors: Wen
mesh_terms: D000328:Adult; D000368:Aged; D000564:Ameloblastoma / Q000473:pathology* / Q000601:surgery*; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology*; D012189:Retrospective Studies; D012983:Soft Tissue Neoplasms / Q000473:pathology* / Q000601:surgery*; D013997:Time Factors