A benign, potentially large peripheral nerve tumour that is most common in the retroperitoneal space, characterised by cyst formation, calcification, hyalinisation, and haemorrhage Management Simple excision
(4) Mitoses are rare and the nuclei are usually cytologically bland with tapered ends; however, nuclear pleomorphism and atypia may occur as a result of degenerative change, the term ancient schwannoma being used when these changes are prominent.
One of them was reported by Inokuchi et al., where a 35-year-old woman who had bilateral adrenal masses had undergone laparoscopic adrenalectomy under the suspicion of a malignant tumor, however, pathologic findings indicated a retroperitoneal ancient schwannoma (4).