腫瘍内出血にて発症した成人横紋筋肉腫の脳転移の1例

Brain Metastasis of Rhabdomyosarcoma with Intratumorous Hemorrhage:A case report and literature review

I．はじめに

　転移性脳腫瘍は全脳腫瘍の5-15％を占めている．その大部分は癌腫であり肉腫の脳転移は稀とされてきたが，最近その増加傾向が指摘されている．われわれは成人胸腔壁原発の横紋筋肉腫の脳転移の1症例を経験したが，成人の横紋筋肉腫自体極めて稀である．また，横紋筋肉腫の脳転移例は渉猟し得たかぎりでは，自験例を含めて17例の報告をみるに過ぎない．そこで若干の文献的考察を加えて報告する．

A 56-year-old male suffered from primary rhabdomyo-sarcoma on the left internal thoracic wall, which was treated by chemotherapy, and local irradiation following biopsy. Four months after the diagnosis, he suddenly complained of headache and left paresthesia occurred followed by generalized convulsion and left hemiplegia. CT scan revealed a high density mass in the right pariet-al lobe. The patient was referred to our department and underwent emergency evacuation of the hematoma together with tumor removal. The pathological specimen showed spindle or oval-like cells with hypercellularity and some mitotic figures. Immunohistochemical study demonstrated that many cells were positive for desmin and myoglobin, which is specific to myogenic tumor. These characteristics were compatible with those of the primary thoracic lesion, and a diagnosis of metastatic rhabdomyosarcoma was made. Five weeks after the cra-niotomy, the metastatic brain tumor recurred in the same site and also in the bilateral occipital lobes. Although radiotherapy to the brain decreased the tumor size, the patient died of respiratory failure eleven and a half months after the initial diagnosis.

Sarcomas metastasizing to the brain are rare and only 16 cases of rhabdomyosarcoma metastasizing to the brain have been reported so far. Recent advances in che-motherapy, however, have been able to show the in-creased incidence of sarcoma metastasis to the brain. Therefore, the necessity of follow-up CT scan for sarco-ma patients of long survival is to be stressed, even if the patient shows no neurological symptoms.