[A case of intracranial osteochondroma: its MR images]

A 15-year-old boy was referred to our department due to left abducens palsy and trigeminal neuralgia. CT scans that had been taken fourteen months before this referral failed to disclose any abnormality. CT scans taken on admission, however, demonstrated an irregular calcified lesion in the left parasellar region. This implied that some ossifying process had been progressing during these fourteen months. MR images clearly demonstrated tumor contour and it was shown that high and low intensity spots were evenly scattered within the tumor. Consequently, tumor appearances in MR images were totally different from those in CT scans. MR images were useful in investigating contour and extension of osteochondroma, but CT scans were necessary to locate calcified foci within the tumor.