Comparative Analysis of the Histopathologic Features, β -Catenin, and Ki67 Expression between Fibromatosis and Fibrosarcoma

Statement of the Problem: The biologic behavior and histopathological features of fibro-matosis are intermediate between those of fibroma and fibrosarcoma. Purpose: The aim of the present study was to determine useful histopathologic and im-munohistochemical characteristics for the differentiation of these lesions. Materials and Method: In this cross-sectional descriptive study, 40 specimens comprising 20 fibrosarcoma and 20 fibromatosis biopsies were selected. The histopathologic characteris-tics of these lesions were identified and immunohistochemical staining for Ki67 and β-catenin markers was performed. Sections were examined by light microscopy and positively stained cells were counted. Results were analyzed by SPSS 20 using Chi-square test, Mann-whitney test, and t-test (p< 0.05). Results: Statistical significant differences were observed between fibromatosis and fibrosar-coma in terms of distribution frequency, mitotic rate, herringbone pattern, cellularity, over-lapping of nuclei, mean Ki67 score, and atypia rate. The other features including age, gen-der, necrosis, clarity of nucleoli and mean β-catenin were not significantly different. Conclusion: The present findings suggest the mitotic figures, Ki67, herringbone pattern, cellularity, and atypia are useful to differentiate fibromatosis from fibrosarcoma.