MICROTUBULE AGGREGATES IN A CLIVAL CHORDOMA

We report a case of a clival chordoma in a 21-year-old man that ultras tructurally demonstrated large numbers of microtubule aggregates withi n the rough endoplasmic reticulum. Histologically, the tumor demonstra ted classic chordoma architecture characterized by numerous physalipho rous cells and an abundant extracellular matrix. The tumor cells stain ed strongly for cytokeratin, S100 protein, and epithelial membrane ant igen, indicative of the epithelial origin of this tumor. Ultrastructur ally, the most conspicuous feature of this tumor consisted of parallel bundles of criss-crossing microtubules within the rough endoplasmic r eticulum. These microtubules had a diameter of approximately 27 nm and did not demonstrate an internal structure. To our knowledge, this is the first report of microtubule aggregates in a spheno-occipital chord oma. We note that microtubule aggregates have been described in a numb er of different entities, and though proposed as a specific feature of ''chondroid chordoma,'' they are a nonspecific finding.