Abstract
Chordoma is relatively uncommon tumor comprising $1\sim4%$ of primary malignant bone tumors, and believed to arise from the remnants of notochordal tissue. Because of its rare occurrence in the thoracic spine, we report a case of chordoma involving the thoracic spine. A 45-year-old male was sufferred from chest pain radiating to the back. Chest CT showed a well marginated, round huge mass with multiseptated enhancement at the thoracic spine from T5 to T8 level. After percutaneous needle aspiration, piecemeal resection of the tumor was done. On cytologic smears, two types of neoplastic cells were arranged in sheets and cords in mucinous background. One type of cells consisted of medium sized cells with pink cytoplasm and round nuclei. The other type had voluminous bubbly or clear cytoplasm divided by intracytoplasmic septae imparting a feathery or basket-like appearance. Histologically, the tumor showed lobulated feature divided by fibrous septae and the tumor cells were pink eosinophilic or physaliphorous in morphology. Immunohistochemically, the tumor cells revealed strong positivity for low(AE1) and high (AE3) molecular weight cytokeratins.