A case of suprasellar ganglioglioma arising from the genu‒rostrum of the corpus callosum composed of tumor cells in various stages of neuronal differentiation

Ganglioglioma was first described by Courville in 1930 and defined as a tumor containing both neuronal and glial components. Gangliogliomas account for 0.3‒1.3% of all primary brain tumors. These tumors appear most commonly in the temporal lobe. Suprasellar gangliogliomas are quite rare, and only 15 cases have been reported to date. The suprasellar region is divided into the optic nerve/optic chiasma/hypothalamus and the corpus callosum/septum pellucidum. Previous reports have shown that suprasellar gangliogliomas are localized primarily in the optic nerve/optic chiasma/hypothalamus region. No tumors have been described in the corpus callosum/septum pellucidum region. Here we present a case of suprasellar ganglioglioma in a 21‒year‒old woman. She presented with a gradually increasing headache over a period of 1 year. She was diagnosed with a brain tumor by her previous doctor, and was subsequently introduced to our department. CT and MRI demonstrated a suprasellar lesion with coarse calcification. The lesion displaced the third ventricle backward, and the bilateral lateral ventricles laterally, and obstructed the foramen of Monro, causing obstructive hydrocephalus. The lesion was completely removed by an interhemispheric approach. Because strong adhesion was observed between the lesion and the corpus callosum, the lesion probably arose from a site around the corpus callosum. Histopathological diagnosis was ganglioglioma. However, the neuronal component consisted of tumor cells of diverse stages of neuronal differentination, including well‒differentiated ganglion cells, neurocytic cells, and small neuroblastic cells. To the best of our knowledge, this case is unique in both the location and differentiation status of the neuronal component.