中脳視蓋部グリオーマの2手術例の検討

Two Surgical Cases of Tectal Glioma

I．はじめに

　今回われわれは，水頭症にて発症した中脳視蓋部グリオーマ（tectal glioma）に対し腫瘍摘出術を行い，病理学的確定診断と水頭症を改善しえた症例を経験したので，若干の文献的考察を加え報告する．

Tectal glioma is rare and difficult to diagnose, and the tumor has been known as the tumor that gives no indication of the need for direct surgery because of its anatomical location. At present, MR imaging is avail-able to detect the tumor and its location. We present two patients who underwent direct surgery.

Case 1: A 18-year-old female was admitted with headache and nausea. MRI showed signs of stenosis of the aqueduct and a tumor of the tectal region. The tumor was removed partially. Histological examination of this tumor demonstrated a low grade astrocytoma. After surgery, hydrocephalus improved.

Case 2: A 12-year-old boy was admitted with hy-drocephalus detected by CT. MRI demonstrated a tumor of the midbrain without confirmation. He underwent a V-P shunt for hydrocephalus, and was discharged with-out any complaints. After 2 years, he was admitted again with shunt malfunction. After shunt revision, his consciousness recovered. However, Parinaud's sign appeared and patency of the shunt was unstable. MRI revealed a tumor of the tectal region and signs of ste-nosis of the aqueduct of Sylvius. The tumor was re-moved directly by the occipital transtentorial approach. The aqueduct was opened and a catheter was inserted from the 3rd to the 9th ventricle. Histological examina-tion revealed a low grade astrocytoma. The patient fol-lowed a satisfactory postoperative course except for slight Parinaud's sign, and the V-P shunt was no longer necessary.