乳癌原発転移性脊髄髄内腫瘍の1例―円錐部病変への外科治療

A Case of Intramedullary Spinal Cord Metastasis from Breast Carcinoma: Surgical Resection for Conus Medullaris Lesion

Ⅰ．はじめに

　転移性髄内腫瘍は中枢神経系への転移の8.5％²⁾，全脊椎転移の0.9～5％⁶⁾を占めると考えられており，原発巣は肺，乳房の報告が多い^1-3,5,8,13)．転移性脊髄髄内腫瘍は稀で現在までの報告は限られている^1-3,5,6)．担癌患者は一般的に生命・機能予後が不良であるため，外科治療は躊躇される傾向があり⁹⁾，放射線治療を推奨する傾向^8,9,13)がある一方，外科治療が有効であった，あるいは外科治療有効例が存在するとの報告^1,3-5)もみられ，治療方針に関する統一した見解がないのが現状である．今回われわれは，手術により良好な結果が得られた脊髄円錐部への転移性髄内腫瘍の症例を経験したので報告する．

　A 46-year-old female presented with gait disturbance and urinary retention which had exacerbated over 3 weeks. The patient had a medical history of breast cancer and brain metastases that had been well controlled by serial chemotherapy and gamma knife irradiation,and had remained independent with Karnofsky performance status (KPS) score of 100 %. On admission,neurological examination detected mild sensorimotor disturbance in the right lower extremity and hypesthesia in the perianal region,in addition to urinary retention and decreased anal tone. Spinal MR imaging demonstrated a well demarcated,heterogeneously enhanced,intramedullary tumor at the L1 level,appearing as isointense on both T1 and T2-weighted images. The patient underwent subtotal tumor resection via hemilaminectomy at the L1 and L2 levels. Postoperatively,the patient's motor weakness and vesicorectal dysfunction showed remarkable improvement,whereas sensory disturbance was only very slightly improved. Histological findings of the tumor were consistent with metastatic breast carcinoma. Surgical resection can be considered for the treatment of intramedullary spinal cord metastasis if the lesion is located in the conus medullaris.