Myolipoma : Immunohistochemistry

Comments:
Immunohistochemistry: As expected, the smooth muscle component in a myolipoma is strongly and diffusely positive for smooth muscle actin (SMA; shown here), desmin, and caldesmon. ER and PR are also usually positive in the smooth muscle cells. HMGA2 immunoreactivity (nuclear) is seen both in spindle cells and fat cells in 60% of cases.