Abstract
A chordoma-like tumor occurred in the coccygeal region of a 101-week-old female ICR mouse. The tumor cells were growing in sheets with a lobular pattern and showed cytoplasmic vacuolation in varing degrees. Markedly vacuolated cells closely resembled the physaliferous cells in human chordoma. Aggregates of cytoplasmic filaments or fibrillar materials in the large vacuoles were demonstrated by electron microscopy.
