DYSEMBRYOPLASTIC NEUROEPITHELIAL TUMORS LOCATED IN THE CAUDATE-NUCLEUS AREA - REPORT OF 4 CASES

OBJECTIVE AND IMPORTANCE: Dysembryoplastic neuroepithelial tumors (DNT s) histologically resemble gliomas but behave as stable lesions. These tumors initially were considered to be located exclusively within the supratentorial cortex. The four reported cases demonstrate that DNTs may also arise in the area of the caudate nuclei. Moreover, the peculi ar topography of these lesions, which suggests a derivation from the s ubependymal plate, is in accordance with the putative origin of DNTs f rom secondary germinal layers. CLINICAL PRESENTATION: The patients exp erienced partial seizures (two patients), generalized seizures (one pa tient), or headaches (one patient). All patients were young (17-26 yr) at the onset of symptoms, and all had normal results from their neuro logical examinations. INTERVENTION: All lesions demonstrated a pseudoc ystic appearance on computed tomographic scans, were hypointense on T1 -weighted magnetic resonance imaging scans, hyperintense on T2-weighte d magnetic resonance imaging scans, and did not show contrast enhancem ent. The four tumors similarly lined the left or right caudate nuclei and expanded within the homolateral ventricle (three patients) or both lateral ventricles (one patient). In one patient, the tumor also invo lved the adjacent paraolfactory cortex. CONCLUSION: In all patients, s tereotactic biopsies helped to identify a specific glioneuronal elemen t of DNTs. None of the tumors was operated on. Radiotherapy was perfor med in only one patient. A long pre- and/or postbiopsy imaging follow- up, which was available in two nontreated patients (3 yr and 16 yr), d emonstrated the perfect stability of the lesion. The occurrence of DNT s in this peculiar location needs to be considered to avoid misidentif ication as ''ordinary'' gliomas and prevent useless aggressive treatme nt.