癌性髄膜炎における髄液生化学的腫瘍マーカーの検討

Measurements of CSF Biochemical Tumor Markers in Patients with Meningeal Carcinomatosis

I．はじめに

　種々の髄液内腫瘍マーカー^9,24）の中にβ—glucuroni—dase，polyamines（putrescine，spermidine，spermine），carcinoembryonic antigen（CEA）があり，β—glucuro—nidaseについては，癌性髄膜炎に特徴的に上昇することが知られている^19,20,23）．Polyaminesは，主に髄芽腫の再発や進展程度の指標としてその有用性は示されており^2,5,14,21），その他にβ—glucuronidaseとともに癌性髄膜炎や悪性腫瘍で高い値を示し15,18），腫瘍の増殖度を表わすとされている^2,18）．CEAについては，転移性脳腫瘍に際し血清CEAの上昇が時に見られるが，髄液CEAの上昇は稀であり，それが高値を示すのは髄膜転移症例¹⁹）や100ng／ml以上の高い血清値を示す症例に多いとされている．

　今回，癌性髄膜炎におけるこれら髄液腫瘍マーカーを調べ他の良性脳疾患・脳腫瘍や充実性転移性脳腫瘍患者のそれと比較することにより癌性髄膜炎の病態の特徴を概要するとともに手術や髄腔内化学療法などによるマーカー値の変動を調べ，これら病態における髄液腫瘍マーカー測定の意義について検討した．

CSF β-glucuronidase, polyamines and carcinoem-bryonic antigen (CEA) were analyzed in 16 patients with meningeal carcinomatosis from solid tumors in systemic organs, 27 with benign brain lesions, 11 with primary brain tumors, 14 with metastatic brain tumors and 5 with leptomeningeal dissemination of other malignant diseases. β- glucuronidase levels in all cases of meningeal carcinomatosis, meningeal gliomatosis and meningeal lymphoma were higher than 100μg/dl/hr. On the other hand, levels in all cases of benign brain lesions were below 100μg/dl/hr. Levels of β-glucu-ronidase in the cases of metastatic brain tumors returned to normal levels after tumor resection. Levels of β-glucuronidase and polyamines were not high in the cases with positive cytology in CSF after tumor resec-tion. The polyamine level seemed to be dependent on the growth rate of the disease and was shown to be be-low 0.05nmol/ml in all cases after resection of the metastatic brain tumors. Cystic fluid of both benign and malignant tumor showed high levels of β- glucuroni-dase and polyamines except for spermidine and sper-mine levels in a suprasellar cyst. Some cases of menin-geal carcinomatosis with high levels of serum CEA did not always show high levels of CSF CEA. In the sur-gical cases with a metastatic brain,tumor, the cases with leptomeningeal, especially dural attachment showed high levels of β-glucuronidase and CEA preoperatively, but they returned to normal after surgery. In 2 cases of meningeal carcinomatosis treated by intrathecal chemotherapy with MTX and Ara-C, CSF β-glucuronidase and CEA showed clinical con-dition better than the cell count in CSF decreased rapidly following chemotherapy.

β-glucuronidase was considered to be a useful CSF marker in the cases of meningeal carcinomatosis to monitor the course of the disease, and CEA was also considered to be a useful marker when CEA levels in CSF are higher than those in serum.