[Two surgical cases of XXXX ].

@entity1 @entity390 @entity850 @entity1276 @entity5 @entity11 @entity816 @entity5033 @entity10
@entity11 is rare and difficult to diagnose, and the @entity5 has been known as the @entity5 that gives no indication of the need for direct surgery because of its anatomical location. At present, MR imaging is available to detect the @entity5 and its location. We present two @entity1 who underwent direct surgery. Case 1: A 18-year-old female was admitted with @entity10 and @entity390 . MRI showed signs of @entity850 of the aqueduct and a @entity5 of the tectal region. The @entity5 was removed partially. Histological examination of this @entity5 demonstrated a low grade @entity816 . After surgery, @entity1276 improved. Case 2: A 12-year-old @entity1 was admitted with @entity1276 detected by CT. MRI demonstrated a @entity5 of the midbrain without confirmation. He underwent a V-P shunt for @entity1276 , and was discharged without any complaints. After 2 years, he was admitted again with @entity5033 . After shunt revision, his consciousness recovered. However, Parinaud's sign appeared and patency of the shunt was unstable. MRI revealed a @entity5 of the tectal region and signs of @entity850 of the aqueduct of Sylvius. The @entity5 was removed directly by the occipital transtentorial approach. The aqueduct was opened and a catheter was inserted from the 3rd to the 4th ventricle. Histological examination revealed a low grade @entity816 . The @entity1 followed a satisfactory postoperative course except for slight Parinaud's sign, and the V-P shunt was no longer necessary.
