Intracranial Meningiomas among Intracranial Tumors in the Neurosurgical Unit of Sylvanus Olympio Teaching Hospital

Objective: To describe the pattern of intracranial tumors in Sylvanus Olympio teaching hospital of Lomé (Togo). Method: We conducted a retrospective and descriptive study between November 2017 and December 2019. Data were obtained from the clinical records of patients with intracranial tumors treated in our neurosurgery unit, and histology obtained. Patients without a definitive histological diagnosis were excluded. Results: 53 patients were operated and had a histological diagnosis in the period of the study. The mean age at diagnosis was 32 ± 27.1 years. The majority of tumors were seen in adults at 88.7% with age range between 23 - 75 years and a mean age of 40 ± 10.5 years. Meningioma was the commonest intracranial tumor in adults (47.2%) and more seen in females. The histological type of meningioma is meningotheliomatous in our study. In children, principal tumors were medulloblastoma and ependymoma (11.3%). Conclusion: Meningioma is the most common intracranial tumor in adults, while embryonal tumors (me-dulloblastoma and ependymoma) are the most frequent in children in our environment.


Introduction
Intracranial tumors arise from the brain or its surrounding tissues. They are a Open Journal of Modern Neurosurgery major cause of morbidity and mortality worldwide [1]. Advances in neuroimaging have improved the diagnosis of intracranial neoplasms. Epidemiologies of intracranial tumors have been reported in Africa [2] [3] [4] [5]. The prevalence of meningiomas among intracranial neoplasms differs from authors [6] [7].
There is limited data on the patterns of intracranial tumors in Togo. The objective of this study is to determine the prevalence of meningiomas among intracranial neoplasms in a single neurosurgical unit of Sylvanus Olympio Teaching Hospital.

Patients and Method
After the approval of the local ethics committee in Sylvanus Olympio teaching hospital, we conducted a retrospective and descriptive study between November 2017 and December 2019, in the neurosurgical unit. Data were obtained from the hospital records of patients undergoing craniotomy for tumor resection. The intracranial tumors were diagnosed by Computed Tomography scan and Magnetic Resonance Imaging. The following data were analyzed: patient demographics (age and gender), presenting symptoms, signs, and histopathology of the tumor. The cases that were excluded from surgeries were patients with Karnofsky Performance Scale below 70, and patients presenting with brain metastases who had an uncontrolled primary disease or multiple brain masses. For each case, we considered the risk to the patients' lives or their morbidity, and keeping in mind the limited intraoperative equipment, to plan the resection extension. All pituitary adenoma were operated in another center with better equipment than ours. In our conditions, intraoperative preparation included positioning without the use of Mayfield headrest ( Figure 1). We didn't use image guidance in any of our patients. Postoperative care for patients was provided by a basically equipped general ICU with no dedicated neurocritical care nursing staff or equipment. No intracranial pression, or electroencephalography monitoring was available in the ICU.

Results
Eighty-two patients with intracranial tumors have been seen during the period.
A total of 53 patients were operated and had a histological diagnosis in the period of the study.
There were more female patients with intracranial tumors, sex ratio = 0.6 ( Table 1).
The mean age at diagnosis was 32 ± 27.1 years. The majority of tumors were seen in adults at 88.7% with age range between 23 -75 years and a mean age of 40 ± 10.5 years. In children, principal tumors were medulloblastoma and ependymoma (11.3%).
Meningioma was the commonest intracranial tumor in adults (47.2%). According to the WHO classification of nervous system tumors, the meningotheliomatous type was the most frequent type ( Table 2). Meningioma had a female preponderance (Table 3)  Pituitary adenoma and metastatic tumors account for 18.8% and 13.2% respectively ( Table 1).
The commonest symptoms and signs in patients with intracranial tumors are resumed in Table 4. The percentages were calculated based on 48 patients with detailed symptomatology.
The majority of tumors were located in supratentorial (Table 5). Figure 3 shows the distribution of meningioma based on location.
In the outcome, the surgical site infection was 3.5%, and the mortality of our series was 13.2%.

Discussion
Intracranial tumors are common in neurosurgery. Those tumors are associated with high morbidity and mortality. The distribution of these tumors varies across the world. In Africa, patients with intracranial tumors have delayed diagnosis due to late presentation [8]. That could explain the low number of cases in our study. Although, as Ekpene et al. [9], the low histological rate is mostly due to missing data resulting from poor record keeping.
In our study, meningiomas accounted for 47.2% of intracranial tumors, and had a female preponderance with a statistically significant (p = 0.025) ( Table 5).
Pituitary adenomas had a frequency of 22% and were seen more in males, according to Jibrin P et al. [18], in Nigeria. In our study, we report a frequency of 18.8% of pituitary adenomas, more seen in males (60%). Olasade et al. [18] [19] and Idowu et al. [12] reported a frequency of 17.1% and 16% in their studies.
Supratentorial sites represented 84.9% of intracranial tumors location. All meningiomas (100%) were located in the supratentorial region. There was a predominance of convexity meningioma (32%), followed by olfactory groove (20%) and sphenoid wing meningiomas (20%). This is similar to the study of Ekpene et al. [9], and Evangelia et al. [11]. The histological type of meningioma is meningotheliomatous in our study. It is similar to Ekpene's study [9] in Ghana. The real incidence rate of intracranial tumors population in Togo, can't be estimated through our study. As Ekpene et al. [9], in Ghana, had observed, based on conjecture, many patients with intracranial tumors don't go to the hospital.
They prefer to seek alternative care in prayer camps and with herbal remedy providers. Also, some of those patients with intracranial tumors, are treated in other health facilities within and outside the country.
In our institution, many problems could explain our high rate of mortality (13.2%): The lack of micro neurosurgical equipment, due to their extreme costs, as mentioned by Hellal et al. [22], in Egypt.
The fact that postoperative care for patients was provided by a basically equipped general ICU with no dedicated neurocritical care nursing staff or equipment [22].
No intracranial perfusion, or electroencephalography monitoring was available in the ICU.

Conclusion
Meningioma is the most common intracranial tumor in adults, while embryonal tumors (medulloblastoma and ependymoma) are the most frequent in children in our environment. Healthcare expenditure impacts neurosurgical practice in our country. Some limitations in expenditure affect patients outcomes.