Ganglioglioma is an infrequent tumor of the central nervous system (CNS); mostly supratentorial region. But, they can occur anywhere in the central nervous system such as brainstem, cerebellopontine angle (CPA), thalamus, optic nerve and spinal cord. Although it occurs rarely, ganglioglioma should be included in the differential diagnosis of a posterior fossa mass because early recognition is important for treatment and patient counseling.
Ganglioglioma is usually a benign slowly-growing neoplasm, and it mainly affects older children and young adults. It accounts for approximately 0.4% of all CNS tumors. It occurs most commonly in the supratentorial region; mostly in the temporal lobe (up to 85%) presenting with long-standing intractable seizures
Nevertheless, there are occasional reports of gangliogliomas occurring in the brainstem, cerebellopontine angle (CPA), thalamus, optic nerve and spinal cord. According to a review of literature, there are only 46 cases of brainstem ganglioglioma. In addition, only few cases have been studied with a magnetic resonance imaging (MRI) scan
We experienced a rare case of ganglioglioma occurring in brainstem, high cervical cord and CPA in a child. Here, we report our case with a review of literature.
A 10-year-old girl was referred to our hospital due to repetitive aspiration pneumonia and seizure lasting over a month. On neurological examination, the patient had a slightly drowsy mental status concurrently with a bilateral lower cranial nerve palsy, horizontal nystagmus and ataxia. Computed tomography (CT) and magnetic resonance imaging (MRI) scans demonstrated a well enhanced mass on the dorsal surface of the brainstem (pons and medulla) and high cervical cord with an exophytic growth posteriorly to left CPA. This mass had a heterogeneous intensity, a slight hyperintensity on T2-weighted images and an isointensity on T1-weighted ones with a contrast enhancement (
The patient received antibiotics for the treatment of pneumonia, followed by tracheostomy and -nasogastric tube feeding for the prevention of aspiration. Two weeks later, the patient underwent surgery through a midline suboccipital craniotomy and a laminectomy down to the C2 level. We performed a removal of the fourth-ventricle mass and left CPA mass near totally, but we could perform only a partial removal of the tumor attached at the posterior aspect of the medulla and high cervical cord.
Histopathologic examinations revealed the presence of low grade ganglioglioma, which was composed of mature and immature ganglion cells without normal perineuronal oligodendrocytes (
On postoperative day 7, the patient had a neurologic deterioration due to obstructive hydrocephalus. The patient therefore underwent placement of the extraventricular drainage catheter. Two weeks later, the patient underwent ventriculo-peritoneal shunt. Postoperatively, the patient presented with a recovery of consciousness but developed the temporary right hemiparesis (Grade IV+) and sleep apnea, both of which were gradually resolved.
At a 10-month follow-up, the patient had a persistent presence of neurologic deficits such as a lower cranial palsy (lack of gag reflex) and a mild gait imbalance.
Ganglioglioma is account for 0.4-7.6% of pediatric CNS neoplasms and up to 1.3% of those in adults
The supratentorial cortical lesions are often characterized by a long history of seizures, whereas posterior fossa gangliogliomas feature focal neurological deficits, cranial nerve palsy, hydrocephalus, increased intracranial pressure, speech or gait changes and myoclonus. In addition, the interval from symptom onset to the diagnosis is significantly shorter as compared with the supratentorial ganglioglioma because the infratentoraial compartment is an anatomically narrow space
Radiographically, there is a great variability in the imaging characteristics of ganglioglioma and it is difficult to distinguish the other brainstem tumor such as subependymomas, ependymomas, or brain stem glioma
Histopathologically, ganglioglioma is characterized by an intimate mixture of abnormal neuronal and glial elements. It is difficult, however, to identify it on histopathology because its reported incidence is relatively lower. This often leads to misdiagnosis of glioma. Immunohistochemical study aids the confirmation of diagnosis of ganglion cell tumor. The glial populations are reactive for GFAP, S-100 protein, and vimentin, but the neurons are for synaptophysin and Chromogranin A
The gold-standard treatment for ganglioglioma is a gross total resection that associates with good prognosis. However, total resection of brainstem gangliogliomas is usually difficult because, brainstem ganglioglioma most often invades the spinal cord or the fourth ventricle that are involved in major cardiopulmonary events. Therefore, brainstem ganglioglioma shows a less favorable outcome as compared with supratentorial one
Nevertheless, a good long-term prognosis can be expected despite a partial removal in cases of brainstem ganglioglioma. According to a retrospective analysis, the 5-year survival rates for cerebral hemisphere, spinal cord, and brain-stem gangliogliomas were 93%, 84%, and 73%. In addition, surgical resection was more effective than biopsy and irradiation
There is still a controversy as to the postoperative use of chemotherapy and radiotherapy. Ganglioglioma has a good prognosis and rarity. Also, radiation therapy would influence development of the central nervous system in children. For these reasons, the study of radiotherapy and chemotherapy to brainstem ganglioglioma is not focused. Although the benefit of radiotherapy is inconclusive, it can be given to patients with a tumor histology showing anaplastic features or oligodendroglial-like cells and recurrence.
Infratentorial ganglioglioma is a very rare entity with a rare location. Nevertheless, ganglioglioma should be included in the differential diagnosis of infratentorial tumor in children. A gross total resection of it cannot be achieved, although survival benefit can be obtained through a more radical resection.
MRI findings. A : T2-weighted images showing slightly high signal intensity mass on the dorsal surface of brainstem and high cervical cord. B and C : T1-weighted images showing an isointensity with a well-enhanced mass.
Photomicrographs of the tumor pathology. Ganglioglioma composed of astrocytes and ganglion cells with dysplastic, binucleated neuron (H-E, ×400).
Immunohistochemical staing. A : Neurons reactive for Chro-magranin (×400). B : Glial cells reactive for GFAP (×200).