側頭骨原発chondroblastomaの1治験例

Chondroblastoma of the temporal bone:a case report

I．はじめに

　軟骨芽細胞腫は，長幹骨骨端部に好発する腫瘍であり頭蓋骨に原発するものは全体の6.8％とされる^3）．今回，われわれは軟骨芽細胞腫が左側頭骨に原発した1例を経験したので報告する．

A 30-year-old male had been suffering from left tern-poralgia of six months duration and then developed left hearing disturbance. Craniogram and bone window CT revealed a well defined osteolytic lesion in the left tem-poral bone. CT scan showed an expansile heterogenous mass with calcification. Both Ti and T2 weighted MRI demonstrated a well lobulated mixed intensity mass, but no evidence of dural or intracranial invasion. The tumor exhibited homogenous enhancement on CT and MRI. Angiogram revealed a well marked staining sup-plied by the left middle meningeal and deep temporal arteries. Subtotal removal of the tumor was carried out with cranioplasty. Histologically, this tumor was com-posed of round or polygonal chondroblasts, scattered osteoclast-like giant cells with a foci of cartilage in the stroma. Many reports describe giant cell tumor can be differentiated by immunohistochemical demonstration of S100 protein. Although in our case, histological find-ings simulated those of eosinophilic granuloma, it was diagnosed as chondroblastoma because of the foci of cartilage in the stroma. Because this tumor is usually benign, recurrence of the tumor is rare after surgical re-section. Post-operative irradiation has been reported to be effective in decreasing the recurrence of the tumor. But it should be carefully observed because of possible sarcomatous change in such tumors.