|Year : 2021 | Volume
| Issue : 1 | Page : 6-11
Computerized tomographic patterns of intracranial tumors in Northwest Nigeria
Suleiman Aliyu1, Phillip Oluleke Ibinaiye2, Nuhu Dung Chom2, Abdullahi Jimoh3, Muhammed Zaria Ibrahim2, Okafor Emeka Kingsley2
1 Department of Radiology, 465 Nigerian Air Force Hospital, Kano, Nigeria
2 Department of Radiology, Ahmadu Bello University Teaching Hospital, Zaria, Nigeria
3 Department of Surgery, Neurosurgery Unit, Ahmadu Bello University Teaching Hospital, Zaria, Nigeria
|Date of Submission||01-Sep-2020|
|Date of Decision||24-Sep-2020|
|Date of Acceptance||25-May-2021|
|Date of Web Publication||22-Jun-2021|
Department of Radiology, 465 Nigerian Air Force Hospital, Kano
Source of Support: None, Conflict of Interest: None
Background: Brain tumors are among the most challenging disorders encountered worldwide. Early and accurate diagnosis is essential for the management of these tumors. Different patterns of distribution of intracranial tumors have been described in various regions of the world, with previous reports in Africa suggesting that brain tumors were uncommon. This relative rarity has been attributed to low detection due to lack of neurosurgical and advanced neuroimaging facilities previously, a limitation that has now been gradually surmounted with the establishment of neurosurgical and more advanced radiological facilities on the continent. Objectives: The objective of this study is to describe the current pattern of intracranial tumors on computed tomography (CT) scan seen in Ahmadu Bello University Teaching Hospital (ABUTH) Zaria, Northwest Nigeria. Methods: This is a retrospective study of CT images of 60 patients of all age groups diagnosed with brain tumors between January 2015 and December 2019. The CT scans of the brain were performed using General Electric Hi-Speed NX/i dual-slice CT scanner (Germany). The age, sex, diagnosis using the WHO histological, and the pattern on CT were recorded, and data were analyzed using Statistical Package for the Social Sciences version 22.0, ARMONK, NY, USA 2013. Only cases with conclusive histology diagnosis were analyzed. This study was approved by the Health Research Ethics Committee of the ABUTH, Zaria (approval Number ABUTH/HREC/M36/2015), on January 23, 2015, before commencement. Results: In the 60 cases of brain tumors studied, patients' age range was 6 months–65 years, with a peak in the fourth and fifth decades of life (accounting for 38.3%). The mean age was 33.04 years ± 17.73 standard deviation. There was equal occurrence among males and females. About 96.7% of the tumors were primary and 3.7% secondary tumors; meningioma (MEN) (45%) was the most common tumor seen. About 45% of the cases were extra-axial, while 55% were intra-axial. Most (81.67%) of the tumors were located in the supratentorial region, while 18.33% were infratentorial. Headache (75%) and visual impairment (53.3%) were the most frequent clinical presentations. Conclusion: MEN was the most common tumor type seen in this study. This corroborates most studies in Nigeria and other African countries but contradicts some studies among Caucasians that showed glioma to be more common. This affirms that racial factors and environmental influence could have significant effects on the pattern of diseases. The results of this study will provide useful data on the pattern of brain tumors in this environment.
Keywords: Brain, computed tomography, Nigeria, tumors, Zaria
|How to cite this article:|
Aliyu S, Ibinaiye PO, Chom ND, Jimoh A, Ibrahim MZ, Kingsley OE. Computerized tomographic patterns of intracranial tumors in Northwest Nigeria. J Radiat Med Trop 2021;2:6-11
|How to cite this URL:|
Aliyu S, Ibinaiye PO, Chom ND, Jimoh A, Ibrahim MZ, Kingsley OE. Computerized tomographic patterns of intracranial tumors in Northwest Nigeria. J Radiat Med Trop [serial online] 2021 [cited 2022 Jan 24];2:6-11. Available from: http://www.jrmt.org/text.asp?2021/2/1/6/319112
| Introduction|| |
Brain tumor is an abnormal growth of tissue in the brain. They cause considerable concern due to their relatively high morbidity, mortality, and enormous cost of care, especially in the developing world where the financial burden is carried by the poor patient and their families. In a study of cancer distribution pattern in southwestern Nigeria, brain tumors accounted for 3.9%. Bailey and Cushing concluded that intracranial neoplasms were not common in Negroes. The relative rarity of intracranial neoplasm in Negroes, especially in Africa is probably related to the lack of neurosurgical facilities and under-diagnosis due to few accessible CT facilities. With the establishment of neurosurgical and more advanced radiological facilities on the continent, intracranial neoplasms are no longer thought to be rare. Common clinical presentations of patients with brain tumors are focal headaches, vomiting, seizures, visual or hearing impairment, hemiplegia/hemiparesis, and cognitive decline.
Reports differ with regards to the pattern of intracranial tumors globally, with some authors reporting meningioma (MEN),,,, as having the highest prevalence while others report gliomas, or metastatic (MET) tumors as the most common intracranial tumors. Gliomas are more common in males, while MENs are more common in females.
Although magnetic resonance imaging is the preferred investigation in patients with suspected intracranial tumors due to its better soft-tissue differentiation and tumor delineation than computed tomography (CT), CT scan was chosen for this study due to its relative affordability, accessibility, shorter scan time, and an open environment for patients with claustrophobia. This study will help to establish a characteristic pattern of brain tumors in this environment.
| Methods|| |
This was a retrospective study of all patients diagnosed with brain tumor using CT scan at Ahmadu Bello University Teaching Hospital (ABUTH), Zaria, Nigeria. ABUTH is a tertiary health institution which serves as a major referral center for neuroimaging and neurosurgery services in northwest zone of Nigeria. The study population was the brain CT scan images of all patients with findings of brain tumor that were also histologically confirmed following surgical excision of the tumors. The study period spanned from January 2015 to December 2019. In this study, the term “brain tumour” referred to any neoplasm, benign or malignant, and primary or secondary found within the cranial cavity. CT images of subjects that could not have surgical excision and histology of the tumor were excluded from this study. Nonneoplastic lesions such as intracranial hematoma of all kinds, vascular aneurysms, inflammatory, and parasitic mass lesions were also excluded. Relevant data were obtained from the medical records, operation registers as well as histopathology reports. The age and sex distribution of the tumors, patients' presenting symptoms, CT/histology diagnosis, relative frequency of the tumors, and anatomical location of the tumors were analyzed. The collected data were analyzed using the Statistical Package for the Social Science version 22.0, ARMONK, NY, USA 2013. Descriptive statistics were expressed in sizes and proportions (percentages, means ± standard deviation [SD]) and presented in the form of tables. In line with the Helsinki Declaration, ethical approval was obtained from the Health Research Ethics Committee of the ABUTH, Zaria (approval Number ABUTH/HREC/M36/2015), on January 23, 2015, before commencement of the study. More so, written informed consent was obtained from patients and/or their relatives.
| Results|| |
A total of 60 intracranial tumors were evaluated during the study period, out of which 58 (96.7%) were primary and 2 (3.7%) were secondary tumors. The age range of the patients was 6 months–65 years with a mean age of 33.04 ± 17.73 years [Table 1].
[Table 2] shows the age and sex distribution. Fourteen cases (23.3%) were children 15 years and below and 46 (76.7%) were adults. The peak age group of tumor occurrence was 31–45 years (accounting for 28.3%). Overall, there was an equal male/female ratio of 1:1.
|Table 2: Age and sex distributions of 60 Brain tumours in all age groups|
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[Table 3] shows the relative frequency of the different histological types of brain tumors seen in this study. MEN was most common, accounting for 45.0% of the cases, followed by pituitary adenoma (PAD) (16.67%). Gliomas as a group constitute 15.0%; these include pilocytic astrocytoma (PAS) (44.45%), glioblastoma multiformes (GBMs) (33.33%) and ependymoma (EPN) (22.22%). Metastasis accounted for 3.33% of the cases.
|Table 3: Relative frequency of the different Histological types of brain tumours|
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Headache (75%) was the most common presenting symptom followed by visual impairment (53.3%), as shown in [Table 4].
In general, as shown in [Table 5], supratentorial (ST) tumors predominate accounting for 81.67% of all the tumors, majority being in adults, while 18.33% were infratentorial (IT), predominantly in children [Figure 1]. All the GBMs, PADs, craniopharyngiomas (CPGs), and MET tumors were ST. The only cases of choroid plexus papilloma (CPP) and pineoblastoma seen were also ST, while all the PASs, medulloblastomas (MED), and schwannoma were IT. MENs were ST in 96.3% of cases and IT in 3.7%. EPNs were found equally in the supra and IT regions of the brain.
|Figure 1: Noncontrast axial and sagittal reformatted computed tomography images show a calcified infratentorial mass with noncommunicating hydrocephalus in a 4-year-old child, confirmed to be an ependymoma|
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[Table 6] shows that majority of the tumors were in the cerebral hemispheres (CH) accounting for 48.37%, followed by the suprasellar (SS) region (28.33%), and 11.67% were in the cerebellum (CRL). Intraventricular (IV) lesions accounted for 6.67%, while the tumors were located in the brainstem (BS), pineal gland, and cerebellopontine angle in 1.67% of cases each. All the GBMs and secondary tumors [Figure 2] were located in the CH, while all the PASs were in the CRL. The MENs were located in the CH in 88.89%, SS in 7.4%, and BS in 3.7% of cases. EPN and MED were in the CH in 50% and IV in 50% of cases.
|Figure 2: Axial noncontrast and contrast-enhanced computed tomography images show an isodense mass in the left parietal lobe with extensive perilesional edema. The mass shows brilliant enhancement. Diagnosis was solitary metastasis from a breast carcinoma confirmed on histopathology|
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[Table 7] shows the sites of predilection of MENs. These include cerebral convexities (33.33%), parasagittal/parafalcine (29.63%) [Figure 3], sphenoid wing (25.93%), SS (7.41%), and brain stem (3.7%).
|Figure 3: Axial noncontrast and contrast-enhanced computed tomography images show a parafalcine isodense mass which shows avid enhancement in the postcontrast image, in keeping with a parafalcine meningioma|
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| Discussion|| |
In this study, 60 cases of intracranial tumors were seen. The results showed that brain tumors affect a wide range of age groups from 1 to 65 years, with peak in the fourth and fifth decades of life (accounting for 38.3%). The mean age was 33.04 years ± 17.73 SD, the disease burden being borne by the active, productive group of the population. Similar age distributions were reported by Olasode et al., in Ibadan Southwest Nigeria; Onakpoya, et al., in Ile-Ife Southwest Nigeria, Soyemi et al., in Lagos Southwest Nigeria, and Hatef, et al., in Uganda, East Africa. In general, there was no sex difference, but specific tumor types show varying sex distributions. MEN is the most frequent intracranial tumor in this study, accounting for 45%; followed by PADs (16.67%) and gliomas (15%). The gliomas seen in this study are PAS (44.45%), GBM (33.33%), and EPN (22.22%). While gliomas have male predilections with a male:female of 8:1, MEN was more common among females with a male:female of 1:1.7. The higher proportion of MEN relative to gliomas in this study is similar to the pattern reported in published reports in the last two decades in Nigeria and other parts of the world.,,, The findings in this study contrast with other studies which reported gliomas as the most common intracranial tumors in Nigeria and worldwide.,,, Lack of stereotactic biopsy equipment in our facility reduced the chances of having a histological diagnosis for most BS gliomas. More so, due to late presentations, MENs are more likely to be operated than gliomas. MET brain tumor which some series also reported as the most common intracranial tumor recorded very low in this study (3.33%). The low prevalence of secondary tumors in this study is in line with observations in reports that resection of MET brain tumor is reserved for patients with the stable systemic disease who are in good neurologic condition. Thus, most patients with metastasis to the brain may be managed without neurosurgical intervention and the benefit of histological confirmation in these patients is therefore missed.
About 11.1% of MEN occurred in children between 11 and 15 years of age and 88.9% occurred in adults; peak age of occurrence was 31–45 years, accounting for 40.7%. Female predominance, with a male:female ratio of 1:1.7 recorded in this study, has also been well established in the literatures.,
PAD accounted for 16.67% of all the tumors and 55.5% of the sellar/SS tumors seen in this study. They show male predominance with a a male:female ratio of 3:2, and all occurred in adults, most within the age range 16–45 years (accounting for 70% of the cases). These findings are comparable to the previously reported pattern in Nigeria and abroad.,
CPG showed bimodal distribution at 6–15 years (40%) and a second peak at 36–55 years (60%), with a female predominance (male:female ratio of 1:4). Bimodal age distribution was also reported by Sutton et al.
Seventy-five percent of MED occurred in the pediatric age group <15 years, with a male:female of 3:1. One case (25%) was seen in an adult. This is in agreement with a study done by Koeller and Rushing.
PAS was the most common form of glioma in this study (constituting 44.44%), with the peak age of 5–9 years accounting for 100% of the cases and mean age of 7 ± 2.3 years, all occurring in male. These findings are similar to those in previous studies, except Olasode et al., who reported female predominance. GBM is the second most common form of glioma in this study with the age range of 28–52 years and mean age of 40.33 ± 12.01 years and a male/female ratio of 2:1. This agreed with the findings in Ibadan where the youngest patient presented at 12 years, confirming that GBM can occur below 30 years. Caucasians, however, have a higher proportion of GBM (which is the most common glioma among them) than africans and it presents in older patients with age range 40–70 years and mean age of 55 years (for primary GBM) and mean age of 40 years (for secondary GBM). The difference in age at presentation could suggest that most GBMs in blacks are secondary transformation of low-grade astrocytomas while most Caucasians present with the more aggressive primary GBM which was reported to occur in older age group.,
The only case of intracranial schwannoma seen in this study was in an 11-year-old boy. Although schwannoma occurs mainly in the middle aged and elderly, its occurrence in childhood has also been reported. The only case of CPP seen in this study was in a 6-month-old child, and it was located in the left lateral ventricle. This is in agreement with Sutton, et al.
About 96.3% of MENs are ST, the most common locations being cerebral convexity (33.33%), parasagittal/parafalcine (29.3%), and sphenoid wing (25.93%). This is similar to findings in the literatures.,
All the MEDs seen in this study were located in the posterior cranial fossa (all in the CRL; 50% in the cerebellar hemisphere, 50% in the vermis extending into the fourth ventricle). One case (25%) was seen in an adult and was located in the cerebellar hemisphere. This is in agreement with previous reports.,
Two cases of EPN were seen in this study, one in the ST region and the other IT, within the fourth ventricle. This is similar to findings in previous studies.,
The primary sources of the MET tumors seen in this study were breast and lung carcinoma. These are the most common primary sites of metastasis to the brain reported. The MET lesion from the breast was located in the parietal lobe. This compares with findings in a study of MET breast cancer by Obajimi et al. in Ibadan, Southwest Nigeria. The two MET tumors seen in this study are located in the ST region in line with the previous report.
| Conclusion|| |
In this study, MEN was the most common tumor seen. ST tumors predominate in adults, while most tumors in children were IT. Headache and visual impairment were the most frequent presenting symptoms. Metastasis, acoustic schwannoma, and CPP seem to be uncommon.
Despite some factors (including one-center study) that may limit the validity of this study, the available data show that the demographic pattern, as well as age and sex distribution, and the tumor location pattern on CT in our study share several features with those reported in other parts of Nigeria and in other countries. However, this study indicates some peculiar epidemiological difference in patterns of MEN in our environment which is notably higher when compared with reports among Caucasians, and this is consistent with other reports which indicate that the incidence of intracranial MEN is high in Africans. This further affirms that racial factors and environmental influence have significant effects on the pattern of diseases. There is, however, a need for a larger population-based multicenter and collaborative studies to achieve a clearer and more accurate pattern of brain tumors in our environment.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]