Deep-seated schwannomas (mediastinum or retroperitoneum) of long standing may show several degenerative changes. They include degenerative-type cytologic atypia, cystic change, calcification, hemorrhage, and dense hyalinization. This image shows Antoni A areas in the right half and Antoni B foci with cytologic atypia and hyalinized blood vessels in the left half. The degenerative atypia consists of irregular, multilobed hyperchromatic nuclei frequently containing intranuclear vacuoles. Despite the cytologic atypia, mitotic activity is not increased. These changes have no prognostic significance.