Cystic vestibular schwannomas: a possible role of matrix metalloproteinase-2 in cyst development and unfavorable surgical outcome.
OBJECTIVE
The authors evaluated the clinical manifestations and surgical results in patients with cystic vestibular schwannoma (VS), and investigated the matrix metalloproteinase (MMP) expression of the cyst fluid and wall in an attempt to elucidate the pathogenesis and characteristics of this disease.


METHODS
The clinical and neuroimaging features, perioperative findings, and surgical outcomes in 24 cases of cystic VS and 82 cases of solid VS, all of which were treated using the suboccipital approach, were retrospectively compared. To evaluate the role of MMP in cystic VS, gelatin zymography and immunohistochemical studies of the cyst fluid, wall, and solid portion were performed in nine cases of this disease. The mean duration of symptoms was shorter (14.0 months compared with 26.1 months; p = 0.04) and the mean size of the tumor was larger (43.8 mm compared with 34.2 mm; p = 0.048) in the cystic than the solid VS group. Although gross-total resection was easier to accomplish in this group (100% compared with 84.1%), adhesion to the facial nerve was more frequent (62.5% compared with 48.8%; p = 0.042). On gelatin zymography studies, MMP-2 expression was ubiquitously observed in all cyst fluids. Immunohistochemical analysis of the cyst wall showed that MMP-2 was apparently localized to the tumor cells on the luminal inner surface, adjacent to the cyst cavity.


CONCLUSIONS
Resection of cystic VS is complicated by severe adhesion of the tumor capsule to the facial nerve and the large size of the lesion. The authors believe that MMP-2 may be involved in the pathogenesis of cyst formation or in its enlargement and may aggravate adhesion to the facial nerve, either by promoting the enlargement of the tumor or engendering the degradation of the tumor-nerve barrier proteolytically.
Moon
Kyung-Sub
KS
Department of Neurosurgery,Chonnam National University Research Institute of Medical Sciences, Chonnam National University Hwasun Hospital and Medical School, Gwangju, South Korea.
Jung
Shin
S
Seo
Seung-Kwon
SK
Jung
Tae-Young
TY
Kim
In-Young
IY
Ryu
Hyang-Hwa
HH
Jin
Yong-Hao
YH
Jin
Shu-Guang
SG
Jeong
Young-Il
YI
Kim
Kyung-Keun
KK
Kang
Sam-Suk
SS
D000293:Adolescent; D000328:Adult; D000368:Aged; D020863:Central Nervous System Cysts / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery*; D003937:Diagnosis, Differential; D005154:Facial Nerve / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000032:analysis*; D020780:Matrix Metalloproteinase 9 / Q000032:analysis*; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery*; D012189:Retrospective Studies; D000267:Tissue Adhesions / Q000601:surgery; D016896:Treatment Outcome
D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9