致死的な腫瘍内出血を来した頭蓋底部chondrosarcomaの1剖検例

Chondrosarcoma of the skull base associated with fatal intratumoral hemorrhage:report of an autopsy case and review of the literature

I．はじめに

　頭蓋内原発のchondrosarcomaは全頭蓋内腫瘍の0.16％のみを占める稀な腫瘍であり，その多くが頭蓋底に発生する^3,5）．組織像がchordomaと類似して，しばしば鑑別診断が困難である．

　今回，突然の腫瘍内出血で死亡した頭蓋底部chon—drosarcoma例を経験したので，免疫組織学的特徴と腫瘍内出血を中心に若干の文献的考察を加えて報告する．

We report a case of intracranial chondrosarcoma of the skull base with fatal intra- and peritumoral hemor-rhage.

A 75-year-old woman complained of right blepharop-tosis and diplopia in 1989. An initial diagnosis of Tolo-sa-Hunt syndrome was made, and the patient was treat-ed with steroid hormone therapy at a local hospital. Because the symptoms had not been relieved, she was admitted to our hospital. Computed tomography (CT) scan and magnetic resonance (MR) images demon-strated a large mass extending from the right side of the clivus to the parasellar region and petrous apex.The mass was partially calcified and had destroyed the base of the middle cranial fossa. The lesion had homo-geneous enhancement with contrast medium. Preopera-tive diagnosis was chordoma or chondroma. A biopsy of the tumor was made. The pathological diagnosis of biopsy specimen was chondroid chordoma. The patient was followed up but no palliative treatment such as radiotherapy was given. on June 25, 1991, she suffered from cerebral infarction. On June 29, 1993, she died of sudden respiratory failure. Autopsy was performed. It revealed intra- and peritumoral hematoma compressing the medulla oblongata, pons and midbrain. Histological-ly immature chondroid cells proliferated in a myxoid-rich extracellular matrix. The tumor cells were com-posed of hyperchromatic nuclei and eosinophilic cyto-plasm, but there was no evidence of notochordal dif-ferentiation. Compared with biopsy findings, the tumor showed high cellular density. Immunohistochemically, the tumor cells reacted positively for S-100 protein, vimentin and cytokeratin, but negatively for epithelial membrane antigen (EMA) and carcinoembryonic anti-gen (CEA). In view of these histopathological findings, the diagnosis of low-grade myxoid chondrosarcoma was established.

Intratumoral hemorrhage often occurs in malignant brain tumors such as glioblastoma and metastatic brain tumor, but chondroid tumors rarely develop a fatal type of intratumoral hemorrhage. Only 8 cases have been re-ported in detail to date. We discuss the immunohisto-chemical features and spontaneous intratumoral hemor-rhage of chondrosarcoma.