Calcifying Aponeurotic Fibroma : Molecular Pathogenesis

Comments:
Molecular Pathogenesis: Calcifying aponeurotic fibroma (CAF) consistently shows a unique genetic anomaly consisting of insertion ins(2;4)(q35;q25) resulting in FN1-EGF fusion. It is considered to be the main driver mutation of this tumor, but its presence is not required for diagnosis. The strong FN1 promoter activity drives inappropriately high expression of the biologically active portion of EGF, which can be detected immunohistochemically.

This image of CAF shows an area of calcification and hyalinization in the center surrounded by circumferential and radiating arrays of chondrocyte-like cells and fibroblastic areas.