Mesenchymal chondrosarcoma of the sellar region.

Abstract

It is known that, although rare, mesenchymal chondrosarcoma can originate intracranially. However, no such malignant tumour has been described in the sellar region. We report a case of mesenchymal chondrosarcoma in a 21-year-old man who presented with double vision, right blepharoptosis and facial pain. Upon initial admission, no endocrinological abnormalities were found, and computed tomography and magnetic resonance imaging revealed a mass with calcification in the sella and right cavernous sinus. For this malignant tumour, three surgical resections, two sessions of gamma-knife radiosurgery, one session of fractional irradiation, and one cycle of chemotherapy were performed, resulting in only brief arrest of the tumour growth. Pathologically, the tumour consisted of undifferentiated small cells of high cellularity, and islands of hyaline cartilage. The undifferentiated small cells showed immunoreactivity for vimentin and ultrastructural features suggesting a mesenchymal origin. Lacunar cells in the islands were immunopositive for S-100 protein and vimentin. Although malignant tumours in the sellar region are rare, they should be considered in the differential diagnosis of various sellar tumours typified by non-functioning pituitary adenoma, and mesenchymal chondrosarcoma is one possible candidate.