title: Histopathologic Differentiation between Enchondroma and Well-differentiated Chondrosarcoma: Evaluating the Efficacy of Diagnostic Histologic Structures.
abstract: OBJECTIVE
  Well-differentiated chondrosarcoma and enchondroma are similar in histopathologic aspects; therefore, special methods should be used to make a distinction between these benign and malignant tumors. The aim of this study was to evaluate the efficacy of a histopathologic method in the long-term follow-up for differentiating these lesions.
  
  
  METHODS
  The medical records of patients with histopathologic diagnosis of chondrosarcoma and en-chondroma were retrieved from the Institute of Cancer, Department of Pathology from 1981 to 2007 in this retrospective study. A total of 14 patients with chondrosarcoma and 7 patients with enchondroma were included. Tumor lobulation pat-tern and fibrous tissue around the lesions were used for histopathologic differentiation between well-differentiated chon-drosarcoma and enchondroma. Method accuracy was evaluated by tumor recurrence in the long-term follow-up.
  
  
  RESULTS
  In the well-differentiated chondrosarcoma group, the follow-up period was 97 months. All the patients (100%) experienced recurrence. In the enchondroma group, the follow-up period was 129 months. There was no recurrence in this group.
  
  
  CONCLUSIONS
  Lobulation pattern and fibrous tissue formation around the tumor can be an effective and helpful indicator for histopathologic differentiation between enchondroma and well-differentiated chondrosarcoma.
authors.affiliation: Professor, Department of Pathology, Institute of Cancer, Faculty of Dentistry, Shahed University, Tehran, Iran.
authors.forename: Shams
authors.initials: S
authors.lastname: Shariat Torbaghan
authors.forename: Mahdi
authors.initials: M
authors.lastname: Ashouri
authors.forename: Noushin
authors.initials: N
authors.lastname: Jalayer Naderi
authors.forename: Nima
authors.initials: N
authors.lastname: Baherini