Gd-DTPA MRIが診断に有用であった大嚢胞性頸髄神経鞘腫の1例

A Case of Macrocystic Cervical Neurinoma Diagnosed by MRI with Gd-DTPA

I．はじめに

　脊髄神経鞘腫は全脊髄腫瘍の約40-60％を占め，最も頻度が高い^3,14）．本腫瘍はその大部分が充実性で，時に小嚢胞形成を伴うことはあるが，充実性の部分が非常に乏しく，大嚢胞を形成した症例の報告は極めて稀である^{1,2,4,11,14,15,17）}．

　今回，著者らはC₅前根から発生し，単房性大嚢胞を形成した極めて稀な頸髄神経鞘腫の1例を経験し，これをGd-DTPA造影MRIにて術前診断し得たので，若干の文献的考察を加え報告する．

　The authors report a rare case of a large cystic cervical neurinoma.

　A 45-year-old female was admitted to our clinic because of motor weakness of the right upper extremity, numbness of the right fingers and right posterior cervical pain. Metrizamide CT myelography demonstrated theoutline of a low density mass. MRI showed a mass revealing low signal intensity on T1-weighted image, high signal intensity on T2-weighted image and marginal enhancement on contrast image with Gd-DTPA. The mass which was diagnosed as cystic tumor, was located in the intradural extramedullary space between C4 to C5 segments. After C4 through C5 laminectomy, the tumor was found to originate from the C5 anterior motor root. The tumor consisted mostly of a cystic part with a very thin solid compartment beneath the capsule. Postoperative course of the patient was uneventful.

　Although spinal neurinoma is one of the most common spinal tumors, an almost completely degenerated large cystic spinal neurinoma is extremely rare. MRI with Gd-DTPA was useful for the diagnosis of the cystic neurinoma by clearly enhancing the margin of the tumor.