OBJECTIVETo study the clinicopathologic features, immunophenotype and histogenesis of dysembryoplastic neuroepithelial tumor (DNT).

METHODSFourteen cases of DNT were retrieved from the archival files of the Department. The histopathologic features and immunohistochemical findings were retrospectively studied. The long-term follow-up data were analyzed.

RESULTSEleven of the 14 cases studied were located in the temporal lobe. Histologically, the tumor consisted of a heterogeneous admixture of neuronal and glial cells (including 1 simple form case, 8 complex form cases and 5 non-specific form cases). The specific glioneuronal element was seen in 9 cases. Variable degrees of cortical dysplasia (CD) were found in 10 out of the 11 cases which had sufficient tissue samples for thorough histologic examination. The morphologic appearance of CD included the presence of heterotopic neurons in molecular layer and/or white matter (7 cases), persistent subpial granular cell layer (4 cases), dyslamination (10 cases) and cellular abnormalities. Immunohistochemically, the oligodendroglial-like cells expressed Olig2. Some of which were positive for nestin, MAP-2, neurofilament and glial fibrillary acidic protein, but negative for NeuN. Long-term follow up revealed that 12 patients had class I postoperative seizure and 2 patients had class II seizure. No tumor recurrence was detected.

CONCLUSIONSDNT is frequently associated with CD. The morphologic diagnosis can be confirmed by immunohistochemical study using a panel of antibodies.