Anaplastic Ganglioglioma: Is it a Sign of Better Prognosis?

Abstract

Aim: Anaplastic ganglioglioma is a rarely seen, high grade malignant glial neoplasm comprising of neoplastic
ganglion cells Since gangliogliomas with an anaplastic astrocytic component are reportedly not always clinically
aggressive, the significance of these tumors remains uncertain. In this retrospective study 30 consecutive high grade
glioma cases within a period of seven years have been re-examined to detect if there were any cases of anaplastic
gangliogliomas. The primary goals were to determine overlooked anaplastic ganglioglioma cases, to examine the
immunohistochemical staining characteristics and find out if there were any prognostic significance of these cases
differing from high grade glial tumors.

Materials and Methods: In this study, 30 documented cases -between 1995 and 2002- with a diagnosis of high
grade glial tumor in the Department of Pathology, İnönü University School of Medicine, were reviewed and
re-evaluated by immunohistochemical means (glial fibrillary acidic protein -GFAP-, neurofilament, neuron specific
enolase -NSE-, and chromogranin A) in order to sort out the anaplastic ganglioglioma cases.

Results: All cases revealed positive staining for GFAP in the glial component. Twenty-two cases revealed positivity
for neurofilament, 26 cases were positive for NSE and 22 cases were immunoreactive for chromogranin A in the
neuronal component.

In the retrospective analysis of the cases, two of them were rediagnosed as anaplastic ganglioglioma. Both cases
were positive for GFAP. Immunohistochemical examinations performed retrospectively including NSE, neurofilament
and chromogranin A revealed cells forming tight clusters or discordant arrangement in addition to binuclear,
multinuclear and atypical ganglion cells.

Conclusion: Anaplastic gangliogliomas are tumors which can easily be misdiagnosed as high grade glial tumors. In our
series, the locations of the tumors were pertinent with the literature. Clinically no patients had an epilepsy history, and one
patient with a good follow-up had a longer median survival than the accustomed shorter survival period in high grade glial
tumors. It is concluded that anaplastic gangliogliomas might have a better prognosis than high grade glial tumors.