Cavernous sinus invasion and tumor proliferative potential of growth hormone-producing pituitary tumors.
OBJECTIVE
Surgical removal of growth hormone-producing pituitary adenomas (GHomas) becomes difficult when they invade the cavernous sinus (CS). We investigated the relation among tumor proliferative potential, tumor volume and invasion of GHomas to CS.


METHODS
15 patients with GHoma aged 20-59 years were enrolled. The volumes of the adenomas were calculated from MR images and the extension to CS was classified into 5 grades according to Knosp's grading system. The immuno-histochemical staining for anti-Ki-67 monoclonal antibody (MIB-1) was performed and the proliferative potential of GHomas was determined as the percentage of MIB-1 labeled nuclei (MIB-1 index). The volume, MIB-1 index and pre-operative growth hormone (GH) level were compared with CS invasion by single and multiple regression analyses.


RESULTS
With single regression analyses, CS invasion was significantly correlated with both the volume (r=0.69, p<0.01) and MIB-1 index (r=0.73, p<0.01), but not with the GH level (r=0.42, p=0.12). The volume and MIB-1 index showed a weak correlation but it was not significant (r=0.52, p=0.06). With multiple regression analysis, CS invasion was well explained by the volume and MIB-1 index of GHomas (r=0.82, p<0.01). About 66% of CS invasion was explained by these two factors.


CONCLUSIONS
In view of these results, not only the volume but also the speed of growth are important for GHomas to invade CS. GHomas with a high MIB-1 index may, even if they are small, more readily invade CS and need closer post-operative hormonal and neuroimaging studies.
Iuchi
S
S
Department of Neurological Surgery, Chiba University School of Medicine, Japan.
Saeki
N
N
Uchino
Y
Y
Higuchi
Y
Y
Tatsuno
I
I
Nakamura
S
S
Yasuda
T
T
Yamaura
A
A
D000236:Adenoma / Q000378:metabolism* / Q000473:pathology*; D000328:Adult; D002426:Cavernous Sinus / Q000473:pathology*; D005260:Female; D019382:Human Growth Hormone / Q000378:metabolism*; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology; D010911:Pituitary Neoplasms / Q000378:metabolism* / Q000473:pathology*; D012044:Regression Analysis
D019394:Ki-67 Antigen; D019382:Human Growth Hormone