CyberKnife Radiosurgery Can Control Recurrent
Epidermoid Cysts of the Central Nervous System
Maziyar A. Kalani, MD, Steven D. Chang, MD, John R. Adler, MD, Iris C. Gibbs, MD, Clara Choi, MD,
Scott G. Soltys, MD and Robert E. Lieberson, MD
Outline Pathophysiology and Radiology Traditional Treatment Options Stereotactic Radiosurgery
Prior publications Stanford experience, 3 patients
Discussion Conclusions
Pathophysiology and Radiology 0.5% to 1.0% of all brain tumors 0.6% to 1.1% of all spinal tumors Cystic
Stratified squamous epithelial lining Desquamation debris, cholesterol,
keratin within cyst
Pathophysiology and Radiology Usually isolated
Lateral, often cisternal Encases nerves and vessels
Symptoms Recurrent aseptic meningitis Mass effect
MRI findings CSF-like in T1 & T2 Restricted diffusion Rarely enhance Differential includes arachnoid cyst
DWI
T1
T2
Traditional Treatment Options Aggressive resection
Gross total resection not possible in 10% to 30% Some recommend perioperative steroids and
intraoperative hydrocortisone irrigation Complications common
Aseptic meningitis Hydrocephalus Recurrence
No benefit from conventional XRT or chemotherapy
SRS – Prior Publications Kida, et al* first reported SRS for
epidermoids in 2006 7 cases Mean follow-up of 52.7 months 2/7 smaller, 5/7 no growth No Complications
We are aware of no other studies
*No Shinkei Geka 34:375-381, 2006.
SRS – Stanford CyberKnife database of 5000
treatments searched Three epidermoids identified,
charts retrospectively reviewed Two spinal One intracranial
Patient BN 48 year old male November 2000 – Subtotal resection 2002 to 2003 – Progressive growth
by MRI July 2006 – Redo-craniotomy with
gross total resection July 2007 – 4.5-cm recurrence by MRI Increasing headaches, seizures
Patient BN December 2007 – CK with
2400cGy to the 79% isodose line, 3 sessions.
November 2010 – MRI with no growth, headaches and seizures medically controlled
Patient DL 53 year old female September 1999 – Two-months progressive
bilateral LE numbness and weakness, no B/B complaints, 1.5 x 3.5 cm conus lesion
October 1999 – T12-L2 laminectomy with GTR. October 2000 – Progression of symptoms,
second resection, 1.5 x 3.8 cm recurrence December 2001 – Progression of weakness,
new B/B dysfunction 2002 – Three percutaneous aspirations
Patient DL – continued July 2002 – CK of 1800 cGy to 81% isodose in one session
November 2010 – MRI with smaller lesion, no pain, incontinence, numbness and weakness
Patient JL 62 year old male 1991 – Presented weakness and incontinence. 1991 to 2002 – Four L3-S1 laminectomies, all
subtotal resections February 2004 – Fifth debulking followed by
CK to resection cavity, 2200 cGy to the 81% isodose in 2 sessions
November 2007 – MRI with no growth compared to 2004, symptoms of pain, numbness and weakness all stable
Patient JL – continued December 2010 – Urinary
incontinence described to authors January 2011 – MRI with a 2.4 x 7.1
x 3.9 cc recurrence February 2004 – Retreated with CK
2400 cGy to the 80% isodose in 3 sessions
Discussion Three patients Intracranial lesion with long term control One spinal lesion required post-CK
aspiration One spinal lesion grew after CK and was
re-treated Before CK therapy, resections every 2.5 years After CK asymptomatic for 6 years
Discussion Spinal epidermoids may be
different from intracranial lesions Cysts are more difficult to treat Can aspirate percutaneously Can re-treat
Conclusions Radiosurgery may stop or delay re-
growth of epidermoids Radiosurgery could potentially be a
primary treatment for some epidermoids
Spinal and intracranial lesions may differ
More studies needed
Merci