胃癌原発側脳室内転移性脳腫瘍の1例

A Case of Lateral Ventricle Metastasis from Gastric Carcinoma

Ⅰ．はじめに

　側脳室内の脳腫瘍は全頭蓋内腫瘍の2%未満と稀であり，髄膜腫，星細胞腫，上衣腫などが代表的である¹⁾．一方，側脳室内に発生する転移性脳腫瘍も稀であり¹⁾，多くは腎細胞癌からの転移²⁾である．今回われわれは胃癌に対して胃全摘術を施行され，8年後に側脳室内転移を生じた1例を経験した．渉猟し得た限り胃癌から側脳室転移を生じた報告例はこれまで1例のみ⁵⁾であり，非常に稀な症例といえる．本症例について文献的考察を含めて報告する．

　Metastatic brain tumors of the lateral ventricles are rare. Approximately half of the reported cases have originated from renal carcinoma;to the best of our knowledge, only 1 case originating from gastric carcinoma has been reported.

　A 57-year-old man presented with dull headache, left hemiparesis, and constructional apraxia of the right upper extremity. He had undergone gastrectomy for gastric carcinoma 8 years previously. Magnetic resonance imaging revealed an enhanced tumor extending from the right caudate nucleus to the right lateral ventricle with peritumoral edema. Complete resection of the tumor was achieved via the right transcallosal approach. The histopathological diagnosis was metastasis from the gastric carcinoma. After the resection, the patient temporarily showed a lack of spontaneity and extrapyramidal signs of the right upper and lower limbs;his condition improved after 3 weeks. He was discharged 2 months after the surgery, without any neurological deficits.

　Patients with tumors of the lateral ventricles may present with various characteristic neurological symptoms in the perioperative period;therefore, a thorough neurological examination is necessary.