Stromal myofibroblasts in central giant cell granuloma of the jaws cannot distinguish between non-aggressive and aggressive lesions

Objective: To investigate correlations between myofibroblast density (MFD) and biological behavior of a large series of non-aggressive and aggressive central giant cell granuloma lesions (CGCGs). Methods: Twenty-four non-aggressive and 17 aggressive lesions were immunohistochemically stained with alpha smooth muscle actin. MFD was assessed using the point counting method in the lesions' core tissue and in control areas that consisted of non-involved, connective tissue surrounding the lesion. Results: All CGCGs contained myofibroblasts among the stromal cells. No significant differences were found in the mean percentage of MFD (%MFD) of non-aggressive (20.8 ± 15.7%) and aggressive (23.7 ± 22.9%) lesions (P > 0.05) or in the mean %MFD of the respective control areas (1.4 ± 2.2% and 1.7 ± 4.1%; P > 0.05). The mean core tissue %MFD of both lesion types was significantly higher than that of the control areas (P < 0.001). Conclusion: Myofibroblasts were an integral component of CGCG stromal cells, but their density could not distinguish between non-aggressive and aggressive lesions.