[1686] Composite Ganglioglioma/Dysembryoplastic Neuroepithelial Tumor: A Clinicopathologic Study of 6 Cases

KM Napekoski, RA Prayson. Cleveland Clinic Foundation, Cleveland, OH

Background: Ganglioglioma (GG) and dysembryoplastic neuroepithelial tumor (DNT) are both low grade glioneuronal neoplasms that most commonly occur in the temporal lobe in association with chronic epilepsy. Rare case reports of tumors with composite features of GG and DNT have been reported.
Design: We retrospectively reviewed the clinicopathologic features of 6 composite GG/DNT tumors (5 females and 1 male; median age at time of surgery 18 years, age range 5-37 years).
Results: All 6 patients had medically intractable epilepsy, tumors in the temporal lobe, and were treated with subtotal resection. Four patients are currently seizure free (postoperative followup intervals: 88, 91, 108, and 140 months); one patient had decreased seizures (postoperative followup interval of 177 months); and one was lost to follow up. Histologically, all of the tumors were multinodular. Half contained two types of histologically distinct nodules: some nodules had features consistent with typical microcystic DNT (range of 15-75% of the tumor) and some demonstrated features consistent with typical GG (range of 10-85% of the tumor). Three tumors contained nodules which demonstrated a hybrid of oligodendroglial type cells mixed with atypical astrocytes and normal appearing neurons. Four tumors demonstrated areas of multinodular GG. Three out of four evaluable tumors demonstrated adjacent malformation of cortical development/cortical dysplasia (Palmini type Ia). None of the tumors contained mitotic activity, vascular proliferation, or necrosis. Two tumors demonstrated focal meningeal extension. Ki-67 immunostaining was performed on 4 of the tumors with indices <1% in all cases.
Conclusions: Composite GG/DNT tumors commonly arise in the temporal lobe in young patients with chronic epilepsy. Histologically, these multinodular tumors appear to maintain distinct areas with features of GG and DNT in addition to foci where the two patterns are merged. A subset of composite GG/DNT tumors appear to be associated with adjacent malformation of cortical development.
Category: Neuropathology

Tuesday, March 23, 2010 1:00 PM

Poster Session IV # 230, Tuesday Afternoon


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