Are low-grade gliomas of mesial temporal area alone?

Abstract

Background: Temporal neocortex which appears normal on magnetic resonance imaging (MRI) may have pathological tissues in low-grade gliomas (LGG) of pure mesial temporal area. Resection of the cortex may be required together with mesial temporal glioma for satisfactory seizure and oncological outcome. The aim of this study was to explore the presence of any pathological tissue on the temporal cortex that appeared normal on preoperative MRI in patients with pure mesial temporal LGGs. Methods: This prospective study included 10 patients who underwent surgical resection of temporal lobe for LGG of mesial temporal area. The temporal neocortex with normal appearance on MRI and mesial temporal area were resected separately, and histopathological diagnosis was performed. Results: LGGs of the mesial temporal area were diagnosed with glioneuronal tumors in 7 (70%) and low-grade astrocytoma in 2 (20%) patients. Regarding the temporal cortex, gliosis and focal cortical dysplasia were found in 7 (70%) and 2 (20%) patients. In one patient temporal cortex did not contain any pathological tissue. All were seizure-free and no tumor recurrence was noted at the last follow-up. Conclusion: Mesial temporal LGGs are not alone and a high proportion of temporal neocortex appeared normal on preoperative MRI, may contain dual pathology. Thus, anterior temporal resection should be performed to have satisfactory seizure and oncological outcomes.

Clinical and Magnetic Resonance Imaging (MRI) Features, Tumour Localisation, and Survival of Dogs with Presumptive Brain Gliomas

“…Lesions in the fronto-olfactory cortex were more often classified as suspected high-grade gliomas, while lesions in the piriform lobe were less frequently considered high-grade. It is likely that, similar to humans, low-grade gliomas in dogs may locate preferentially in the piriform lobe and invade mesial temporal areas [16,19,20]. However, this is not supported by previous studies in dogs based on a histopathological diagnosis of tumours, although in these previous studies, the piriform lobe was not considered separately [5,12,29].…”

“…Age at presentation ranged from 4 to 15 years with the median (IQR) of 9 (7-10) years. Body weight ranged from 4 to 55 kg with the median (IQR) of 14 (12)(13)(14)(15)(16)(17)(18) kg. Breeds included French Bulldogs (40 dogs), Boxers (6 dogs), mixed breed dogs (5 dogs), Yorkshire Terrier (2 dogs), and one each of the following breeds: English Bulldog, Boston Terrier, Cavalier King Charles Spaniel, West Highland White Terrier, Staffordshire Bull Terrier, Cane Corso, and Dogue de Bordeaux.…”

“…In humans, the predisposition for developing ES depends on the localisation and grade of the tumour [15]. Mesial temporal gliomas are associated with higher epileptogenicity [16]. In addition, low-grade gliomas are more epileptogenic than high-grade gliomas [17,18].…”

“…In addition, low-grade gliomas are more epileptogenic than high-grade gliomas [17,18]. Since low-grade gliomas have an increased affinity for the mesial temporal area in adults [16,19], drug-resistant epilepsy is their most common symptom [17,18]. Investigations of animal models have also indicated that the piriform lobe, located at the edge of the olfactory and mesial temporal cortex, is one of the most epileptogenic regions in the brain [20,21].…”

Beyond the neuro-oncological outcome: A perspective of the seizure control after resection of the medial temporal lobe gliomas

“…They believe that LGGs are not limited to the area shown by MRI, and part of the normal temporal neocortex in preoperative imaging may also be involved by the tumor histologically. [ 2 5 6 7 ]…”