Tomography, Vol. 8, Pages 2844-2853: Suprasellar Ganglioglioma Arising from the Third Ventricle Floor: A Case Report and Review of the Literature

The term ganglioglioma, first referred to by Perkins in 1926 and popularized by Courville in 1930, is used to describe a type of central nervous system tumor containing astrocytic and neuronal components, the pathogenesis of which is unknown. According to a statistical analysis of 326 ganglioglioma cases, the mean age of onset in the 279 ganglioglioma grade I tumors was 22.1 ± 11.2 years old, 30 grade II ganglioglioma cases had a similar age distribution, and in 17 anaplastic gangliogliomas (WHO grade III), the mean age was approximately 35 ± 14.5 years old [1]. The main symptom of gangliogliomas in the temporal lobe is refractory epilepsy [36], while in other parts, it is generally caused by focal nerve compression or increased intracranial pressure [4,9,10,26,34]. Infratentorial GGs may present with cerebellar signs, cranial nerve deficits, or, rarely, increased ICP [37]. Intracranial GGs are most commonly found in the temporal lobe, but rarely in the pituitary gland, pituitary stalk, optic pathway, hypothalamus, ventricle, and spinal cord. Most GGs grow slowly and have clear boundaries, cystic components, and calcifications. GGs are generally classified as WHO grade Ia, and some GGs have anaplastic features and are considered to be grade III ganglioglioma (anaplastic GG). If the tumor contains mitosis, necrosis, and microvascular proliferation, it is generally a WHO grade IV ganglioglioma with glioblastoma changes [38]. Histopathologically, the admixture of neoplastic cells and abnormal ganglion cells is the diagnostic marker; ganglion cells can be identified by the presence of Nissl substance and large nucleoli [39]. It is known that ganglion cells or neurons in GGs are dysplastic due to cellular disorganization, subcortical localization, aggregation, and the accumulation of giant cells and Nissl substance around the membrane [1]. Immunohistochemistry staining for glial fibrillary acidic protein (GFAP), S-100 protein, and neuronal markers (Neun, Syn) helps to identify neuronal and glial cell populations. The semi-quantitative assessment of the Ki-67 labeling index helps characterize the biological behavior of the tumors [39]. A study found that the expression of CD34 in GGs may be related to the location of the tumor, and the staining in temporal lobe lesions was mostly positive for CD34, while in other rare sites it was mostly negative [1]. Generally, low-grade GGs have a low Ki-67 index (p53 mutations. Tumors with high levels of p53 mutations and a Ki-67 index generally have anaplastic features, which may suggest high-grade features [40].On imaging, GGs can be divided into cystic tumors (more than a 90% cystic component), cystic solid tumors (cystic component 10–90%), and solid tumors (cystic component less than 10%), of which cystic tumors account for about 44–80% [41]. In the MRI images, GGs generally present an iso-intense signal or a slightly hypo-intense signal on T1-weighted images, and a hyperintense signa in T2-weighted images. Generally, there is no peritumoral edema. When an edema occurs, it generally indicates a malignant lesion [42]. About half of GGs show an enhancement in MRI images after gadopentetate dimeglumine injection, and the degree of enhancement is inhomogeneous. It usually appears as a low-density lesion on the CT, with varying degrees of enhancement or calcification [43].Generally, GGs present a slow-growing trend, and their clinical manifestations are slow. Surgical resection generally leads to good prognosis. In general, on the premise of preserving the integrity of neurologic function, a total tumor resection should be considered to be of the utmost priority. However, since the suprasellar region has a complex structure and is close to important blood vessels and nerves, biopsy has become an alternative method. According to the data, the 10-year survival rate of these patients after total tumor resection is 82–93% [44]. We believe that GG is also characterized by a low recurrence rate. According to the statistics of Professor Blümcke et al., among the 86 patients diagnosed with ganglioglioma (WHO grade I), only 1 patient relapsed after 7 years of follow-up, and no tumor recurrence was recorded in the 19 patients we counted [1]. Upon admission, patients can choose between craniotomy and transnasal endoscopic surgery, especially in the case of our study. The principal reason that we chose to perform transnasal endoscopic surgery was that it can better expose the important structure surrounding the tumor. Second, it is minimally invasive and scarless, and allows direct entry to the skull base. No manipulation of neurovascular structures is required. In addition, the transnasal approach allows us to obtain a good view of the hypothalamus and other structures. In comparison to traditional craniotomy, the incidence of brain injury and cerebrovascular accident is significantly lower, but cerebrospinal fluid leakage is more likely to occur [45]. For GGs that can be enhanced on preoperative MRI, some literature studies suggest that better results can be obtained with fluorescein-guided surgery, whether surgical resection or surgical biopsy [46]. Therefore, during the operation, we used artificial dura mater and a vascularized pedicle nasoseptal flap to repair the bottom structure of the sella, thus reduced the chance of cerebrospinal fluid leakage. We believe that endoscopic transnasal surgery is a better option. Currently, there is still no clear evidence supporting the need for adjuvant therapy following surgery for GGs. However, certain data show that adjuvant radiotherapy can prolong the interval of recurrence, although it does not improve the overall survival rate [47]. In addition, chemotherapy has also been applied for this type of tumor. In our literature review, Vajramani et al. [13] used temozolomide for chemotherapeutic purposes, and Spennato et al. [16] used temozolomide and imatinib. We cannot form a conclusion due to the limited results.

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