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