Degenerated neurilemoma (ancient schwannoma)

We report a case of degenerated neurilemoma in a 65-year-old Japanese woman. A tumor in the right thigh histopathologically showed a mixture of Antoni type A and B patterns, and contained prominent blood vessels with hyalinized walls, but no calcification. The tumor cell nuclei of middle areas were large, hyperchromatic and often multilobed but lacked mitotic figures. The mucinous areas had few tumor cells. Antoni type A and B areas were S-100 protein positive, while mucinous areas and hyalinized vessels were negative.