Schwannoma : Ancient Change
Deep-seated schwannomas (mediastinum or retroperitoneum) of long standing may show several degenerative changes. They include degenerative-type cytologic atypia (irregularly enlarged multilobed hyperchromatic nuclei, intranuclear vacuoles), cystic change (shown here in this low-power scan), calcification, hemorrhage, and dense hyalinization. The hyalinized stroma frequently contains hemosiderin-laden macrophages and inflammatory cells. Despite the cytologic atypia, mitotic activity is not increased. These changes have no prognostic significance.