{Reference Type}: Journal Article
{Title}: White epidermoid cyst transformation after stereotactic radiosurgery: illustrative case.
{Author}: Matsumoto H;Shinya Y;Miyawaki S;Shin M;Koizumi S;Sato D;Hinata M;Ikemura M;Kiyofuji S;Kin T;Iwanaga M;Shimizu M;Nakatomi H;Saito N;
{Journal}: J Neurosurg Case Lessons
{Volume}: 5
{Issue}: 24
{Year}: 2023 Jun 12
暂无{DOI}: 10.3171/CASE2376
{Abstract}: <B>BACKGROUND: </B>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.<BR><B>METHODS: </B>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.<BR><B>CONCLUSIONS: </B>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.