%0 Journal Article
%T White epidermoid cyst transformation after stereotactic radiosurgery: illustrative case.
%A Matsumoto H
%A Shinya Y
%A Miyawaki S
%A Shin M
%A Koizumi S
%A Sato D
%A Hinata M
%A Ikemura M
%A Kiyofuji S
%A Kin T
%A Iwanaga M
%A Shimizu M
%A Nakatomi H
%A Saito N
%J J Neurosurg Case Lessons
%V 5
%N 24
%D 2023 Jun 12
%M 37334973
暂无%R 10.3171/CASE2376
%X BACKGROUND: White epidermoid cysts (WECs) are a rare type of epidermoid cyst with atypical radiological features. The epidemiological aspects and mechanisms of their onset remain unknown. Herein, the authors report a unique case of WEC transformation from a typical epidermoid cyst after stereotactic radiosurgery (SRS), confirmed by radiological and pathological findings.
METHODS: The case involved a 78-year-old man with a history of 2 surgeries for a left cerebellopontine angle typical epidermoid cyst 23 years earlier and SRS using the CyberKnife for recurrent trigeminal neuralgia (TN) 14 years earlier. The tumor with high intensity on T1-weighted imaging, low intensity on T2-weighted imaging, without restriction on diffusion-weighted imaging had gradually enlarged after SRS. Therefore, a salvage surgery was performed via a left suboccipital craniotomy, and the intraoperative findings showed a cyst with a brown, viscous liquid component, consistent with those of WECs. Histopathologically, keratin calcification and hemorrhage were identified, leading to a diagnosis of WEC. The postoperative course was uneventful, and the TN resolved. No tumor recurrence was recorded at 2 years postoperatively.
CONCLUSIONS: To the best of the authors' knowledge, this is the first world case of WEC transformation from a typical epidermoid cyst after SRS, confirmed by radiological and pathological findings. Radiation effects could have been involved in this transformation.