Cardiac Fibroma : Microscopic Features

Comments:
Microscopic Features: Cardiac fibromas are composed of bland fibroblastic cells in a dense collagenous stroma. There is no cytologic atypia or increased mitotic activity. Lesions in young patients (< 6 months old) are quite cellular and mitotically active and may be confused with low-grade fibrosarcoma. With advancing age, they become more collagenous and less cellular and can resemble an old scar. The tumor cells have myofibroblastic features and are positive for vimentin and SMA and are negative for CD34, S100, and HMB45.