Dysembryoplastic neuroepithelial tumor (DNT)-like oligodendrogliomas or DNTs evolving into oligodendrogliomas: Two illustrative cases

Abstract

A review of dysembryoplastic neuroepithelial tumors (DNTs) in 14 patients over a 12-year period revealed four patients re-operated because of changes on magnetic resonance imaging (MRI) suggesting tumor recurrence or progression. In three of these, the histological features were identical to the initial DNT. In the fourth patient, persistent DNT was surrounded by WHO grade 2 oligoastrocytoma. In one of the other 10 patients, WHO grade 2 oligodendroglioma was present in white matter deep to and completely separate from a cortically based DNT. Fluorescence in situ hybridization showed codeletion of 1p and 19q in both the DNT and oligodendroglioma and oligoastrocytoma components. Deletions were..