[1699] Papillary Glioneuronal Tumors — Clinicopathological and Ultrastructural Studies

JH Seo, BM Kim, JK Myung, CK Park, SH Park. Seoul National University Hospital, Seoul, Republic of Korea

Background: Papillary glioneuronal tumor (PGNT) is an uncommon and morphologically distinct glioneuronal tumor originally described by Komori et al. in 1998. [2]. It is characterized by a biphasic pattern of pseudopapillary structures and solid sheets of monotonous cells with an often myxoid background.
Design: Clinicopathological analyses of 4 recent cases of PGNT were conducted, including immunohistochemical and ultrastructural examination and assessment of biological behavior.
Results: The patients ranged in age from 12 to 75 years (mean age: 28.4 years), had a male to female ratio of 3:1, and presented with seizures (n = 3) or muscle spasms (n = 1). The tumor location was supratentorial [frontal lobe (n = 3) and parietotemporal lobe (n = 1)]. Radiologically, they were large cystic mass with an enhancing cyst wall and mural nodules. There were 2 cases of atypical grade and 2 cases of low grade PGNTs (WHO grade I). The two atypical cases showed a high mitotic rate (4–7/10 HPF), and vascular endothelial hyperplasia and necrosis. The tumor cells were immunolabelled for glial and neuronal markers. Ultrastructural analysis revealed that these neoplastic cells exhibited characteristics of either astrocytic or neuronal differentiation, such as glial-type intermediate filaments, microtubules, and synapses with synaptic junctions and synaptic vesicles. Our patients were symptom- and progression-free, without tumor recurrence, for up to 12 to 26 months after gross total resection.
Conclusions: These cases led us to conclude that PGNT is unique among the glioneuronally-differentiated tumors, and most probably arises from neural progenitor cells. The follow-up duration of the present study was not sufficiently long to determine the biological behavior of the PGNTs, which were considered WHO grade I, but could have been of a higher grade.
Category: Neuropathology

Tuesday, March 23, 2010 1:00 PM

Poster Session IV # 231, Tuesday Afternoon

 

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