Central nervous system tumours in children in Ibadan, Nigeria: a histopathologic study
Gabriel Olabiyi Ogun1, Amos Olufemi Adeleye2, Taiwo Olaosebikan Babatunde1, Olufunmilola Abimbola Ogun3, Ayodeji Salami1, Biobele Jotham Brown4, Effiong Akang1
1Department of Pathology, College of Medicine, University of Ibadan, and University College Hospital, Ibadan, Nigeria, 2Division of Neurological Surgery, Department of Surgery, College of Medicine, University of Ibadan and University College Hospital, Ibadan, Nigeria, 3Neuro-Ophthalmology Unit, Department of Ophthalmology, College of Medicine, University of Ibadan, and University College Hospital, Ibadan, Nigeria, 4Oncology Unit, Department of Paediatrics, College of Medicine, University of Ibadan and University College Hospital, Ibadan, Nigeria
Gabriel Olabiyi Ogun, Department of Pathology, College of Medicine, University of Ibadan, and University College Hospital, Ibadan, Nigeria
contrary to some earlier teachings that central nervous system (CNS) tumours
are uncommon in black children, these neoplasms are the fourth most common paediatric
tumours in Ibadan. Our centre is the major referral centre for CNS tumours in
Nigeria. The last major study of paediatric CNS neoplasms from Ibadan was in
1985. An update of the data on paediatric CNS neoplasms at our centre is presented.
a retrospective review of all histologically diagnosed CNS tumours in children (0-14 years) from January 2001 to December 2010 from the database of the Department of Pathology, University College Hospital,Ibadan, Nigeria was done. The cases were classified using the 2007 WHO Classification of Tumours of the Central Nervous System and were also based on their supratentorial and infratentorial locations.
seventy-seven tumours, 44 in males, were included in the study. Astrocytic tumour comprised 20 cases, embryonal tumours 15, ependymal tumours 15, germ cell tumours 6, sellar tumours (all craniopharyngiomas) 9 and other histological types- 12 cases. Thirty-seven were WHO Grade 1, eleven Grade 2, ten Grade 3 and nineteen Grade 4 neoplasms. Thirty-six cases were supratentorial and thirty-eight were infratentorial in location. The most common tumours in this series were pilocytic astrocytomas, medulloblastomas, craniopharyngiomas and ependymomas in that order.
childhood CNS tumours are being increasingly diagnosed in our centre. This is largely explained by the recent expansion of the available neurosurgical services.
Only three decades ago, it was widely believed that the incidence
of gliomas was relatively low in blacks children, when compared
with Caucasian children [1, 2].
Although central nervous system(CNS) neoplasms are the second most common
in Caucasians series [3-5], they only rank as the fourth
most common paediatric tumour in the past studies in Ibadan, Nigeria
Furthermore, a recent review of paediatric neoplasms from Ibadan
documented a six-fold increase, from 2.2% to 12.9%, in the relative frequency
CNS neoplasms over a period of five decades . Another
study in 2007 revealed that 37% of all CNS neoplasms at our centre
occurred in children . It is speculated that a similar
trend can be infered for other centres in Nigeria. The reason that can be
for this is the recent modest increase in access to high-resolution
diagnostic tools such as computed tomography (CT) scanning and magnetic
(MRI). Our nation has also recently begun to witness a progressive
increase in the critical mass of competent clinical neuroscientists including
in neurosurgery, adult and paediatric neurology, neuroradiology,
neuropathology and neuro-ophthalmology, as well as some other ancillary
The CNS is an extremely complex and specialised system known to
harbour an array of approximately 130 primary neoplasms .
The pattern of CNS tumours in childhood differs in terms of the
histopathologic subtypes as well as the anatomical location from those in
the main tumour groups in children are astrocytomas (38-50%), ependymoma
(8-14%), primitive neuroectodermal tumours (PNET), including medulloblastoma(16-25%),
and other gliomas (4-16%) .
The distinction between benign and malignant neoplasms is blurred in the brain;
in that all CNS neoplasms may eventually be attended by fatal raised
intracranial pressure (ICP), irrespective of the degree of histological
In this respect, and especially so in many countries in sub-saharan
African , many childhood CNS neoplasms often only come to clinical awareness
their initial non-specific symptomatology has evolved to more terminal
ones like those of raised ICP. There is a gross lack of data on the demographic
patterns of paediatric CNS tumours in many developing countries
of the world
due to non availability of reliable data collection, poor infrastructure
for cancer registries and many other logistic constraints.
Since the last major study of childhood CNS neoplasm from our centre in 1985,
there has been no further attempt at a review targeted primarily
at childhood CNS tumours in Ibadan, Nigeria, the nation's flagship centre
and academic neuroscience . The aim of this present
study is therefore to update the data on childhood CNS tumours
at our centre, describe the histopathological pattern, and determine the
of the tumours. We also made an attempt at comparison with the
previous two studies from our centre as well with a few studies from other
of the world.
This is a retrospective data base study of childhood tumours of the central nervous system (CNS) diagnosed in the Department of Pathology, University College Hospital, Ibadan, Nigeria between January 2001 and December 2010. All CNS neoplasms in children aged 0-14 years were retrieved from the files and records of the department including autopsy records and from the records of Ibadan Cancer Registry (our department falls under its jurisdiction). Also a systematic review of the literature was also performed.
Cases that were not histopathologically confirmed were excluded from the study. The data abstracted from patients records include age (stratified into 0-4 years, 5-9 and 10-14), gender, intracranial location of the tumour (either supra or infratentorial), and the specific histological diagnosis. The cases were classified using the 2007 WHO Classification of Tumours of the Central Nervous System after reconfirmation of the diagnosis . Immunohistochemistry was used in the confirmation of some cases where necessary.
The data obtained was entered into the Statistical Programme for Social Sciences, version 20 (SPSS Inc, IL, USA) and subjected to analysis.
This study was conducted in compliance with the guidelines of the Helsinki declaration on biomedical research in human subjects. Confidentiality of the identity of the patients and personal health information was maintained.
Seventy seven tumours were included in the study out of which 44 (57%) were males with a male to female ratio of 1.3:1. The ages of the patients ranged from 29 days of life to 14 years with a mean of 7.2 years and a median of 7 years. Thirty-one cases (40.3%) occurred in the age bracket 0-4 years, 27 (35.1%) in 5-9 years and 19 cases (24.7%) in 10-14 years. In all there were 36 cases (46.8%) that were WHO Grade 1, 12 cases (15.6%) were Grade 2, 10 cases (13.0%)- Grade 3, and 19 (24.7%) were Grade 4 neoplasms (Table 1). In other words, 37.7% of the childhood tumours of the CNS in Ibadan were of the histologically malignant variety. Majority, 16 out of 29 (55.1%) of these occurred in the 0-4 years age group (Table 1).
Overall, astrocytic tumours comprised 20 (25.9%), embryonal tumours 15 (19.5%), ependymal tumours 15 (19.5%), sellar tumours- all were craniopharyngiomas 9 (11.7%), germ cell tumours 6 (7.8%), meningeal tumours 7 (9.0%) and other histological types made up the remaining 5 cases.
the 20 cases recorded comprised of 17 grade one tumours (16 pilocytic astrocytomas and one case of subependymal giant cell astrocytoma), a single Grade 2 tumour (fibrillary astrocytoma) and two glioblastomas.
these comprised 13 medulloblastomas, and a case each of ganglioneuroblastoma and ependymoblastoma.
these comprised a single case of myxopapillary ependymoma, 10 ependymomas and 4 cases of anaplastic ependymoma. Table 2
show details for all the tumours in this series.
Thirty-eight (50.6%) cases were infratentorial and thirty seven (49.4%) were supratentorial in location. There were two spinal region neoplasms. Table 3
shows the details of the distribution of the tumours.
A recent 5-year (2004-2008) review of data from the Ibadan cancer registry shows that, overall, CNS tumours accounted for 2.5% of all newly diagnosed registered tumours . However, childhood tumours were not well segregated from those of adults in the publication. This lack of segregation is what is commonly observed in studies on CNS tumours from developing countries [7,12].
In many developing countries, including Nigeria, there are significant logistic constraints to a complete hospital data collection and population based studies are virtually impossible to carry out. Hence, most times, hospital based studies are the only source of useful data available to describe the pattern of paediatric CNS tumours. These, in spite of their known unreliability are then sometimes extrapolated for the population [10,12] .
This current study is the second attempt at detailed documentation of childhood CNS tumours from our centre. The first attempt covered a period of 22 years (1960-1982)  and was a report dating back 3 decades. A second study that covered an 11 year period was an overview of CNS tumours in adults and children with some separation in both categories . Table 4 shows a comparison of these two earlier studies with the current one.
Consistently, astrocytic tumours have remained the commonest primary CNS neoplasms in children at our hospital though with a downward trend in the percentage from 39% to 25.9% in the current study [10,12]. A distinctive finding in the current study is the almost complete absence of secondary tumours. A comparison to the two previous studies from our centre by Aghadiuno et al and Olasode et al show a high percentage of secondary involvement of the brain by Burkitt's lymphoma [10,12]. None was observed in the present study. This trend of sustained decreasing incidence of Burkitt´s lymphoma as an entity and with its attendant secondary involvement of the CNS has been observed in the last two decades . We are of the opinion that the significant improvement in the treatment of malaria and some measure of improved nutrition in children from our country have led to this trend.
Furthermore, ependymomas which were of insignificant proportion in the previous two studies have emerged to become the second commonest tumours after the astrocytic tumours. Because of the corresponding relative decline in astrocytic neoplasms observed in the present study, it may be that some neoplasms recorded as astrocytic tumours in the previous two studies might actually have been ependymal neoplasms.
A comparison of the current study with some other studies from different parts of the world, (Table 5
), shows that generally astrocytic tumours are the commonest neoplasms in most regions of the world. Though, astrocytic tumours account for 25.9% in our series, their frequency is much higher ranging from 30.5% to 47.3% in series from Europe, Asia and South America [13-20
In this study ependymoma was the second ranked tumour, accounting for 19.5% of cases. This is in contrast to all the other studies we have compared with the current study, in which the frequency ranged from 4.8% to 10.5% [14
]. The retrospective nature of this analysis precludes any meaningful speculations to explain this trend.
Medulloblastomas accounted for 16.8% of cases in our study and ranked the third most common tumour. This ranking and percentage of its relative frequency is comparable to that of 10 to 18.4% recorded in studies from Asia and Europe as illustrated in Table 5
]. The exception to this was a study from Pakistan where medulloblastoma accounted for 45.6% of cases in that series [21
Generally boys are usually more affected than girls with regards to paediatric CNS tumour. The ratio of 1.3:1 is similar to studies from Germany, Iran and Japan [14
]. A higher male:female ratio was recorded in studies from China and India [15
]. Furthermore a 2.5:1 male preponderant ratio was recorded in the Pakistani study, though gender bias favouring boys having easy accesses to health care as a socio-cultural practice might be responsible [12
The mean age in this series was 7.3 years. This is somewhat relatively lower when compared to studies with similar maximum age limit of 14 years inclusion criteria. The studies from Germany, Iran, Pakistan had mean age of 10.7, 8.8 and 8.8 years respectively [14
]. This difference may not be explainable from the age structure in our country where the higher percentage of the population is children. Higher mean age is observed in studies with higher maximum age limit as inclusion criteria for such studies.
In the current study, there was almost an equal ratio between supra- and infra- tentorial tumours. This is similar to the finding of Kaatsch et al and Mehrazin et al from Germany and Iran respectively. However, studies from China, South Korea, India and Brazil show a preponderance of supratentorial tumours [4
]. Infratentorial tumours were more commonly seen in the studies from Pakistan [21
In conclusion astrocytic tumours, ependymomas, medulloblastoma and craniopharyngiomas account for about 73% of intracranial tumours of children aged 0-14 years of age in this study. Certain differences exist in the frequency of occurrence of the tumours between this study and others. However, this represents a picture of the paediatric brain tumours that came to our attention and that were histologically diagnosed in the particularly challenging African environment where we practise.
What is known about this topic
- Central nervous system tumour are rare in Black children;
- Asrocytic tumour are the commonest CNS tumours in children.
What this study adds
- Increasing diagnostic capabilities at UCH has resulted in an increased identification of CNS tumors;
- This is a good audit of the UCH experience in terms of histopathologic pattern of CNS tumours.
All authors declare no competing interest.
GOO conceived, wrote the original draft and did analysis of data,
AOA conceived and wrote part of the manuscript, TOB collated the
data, did the analysis of data and wrote part of the manuscript,
OAO,AAS, BJB and
EEA contributed to the design and wrote part of the manuscript.
All authors read and approved the final manuscript.
Table 1: age group distribution and WHO grades of CNS neoplasms in children in Ibadan
Table 2: paediatric CNS neoplasms in Ibadan, Nigeria: gender and age group distribution of all tumours in the series
Table 3: paediatric CNS neoplasms in Ibadan, Nigeria: Morphologic sub-types in relation to Anatomical locations
Table 4: paediatric CNS neoplasms in Ibadan, Nigeria: Comparison of the two previous studies from Ibadan with the current study
Table 5: paediatric CNS neoplasms in Ibadan, Nigeria: Comparison of our study findings with some other series from different parts of the world
- Williams AO. Tumors of childhood in Ibadan, Nigeria. Cancer. 1975 Aug; 36(2):370-8. PubMed | Google Scholar
- Olisa EG, Chandra R, Jackson MA, Kennedy J, Williams AO. Malignant tumors in American black and Nigerian children: a comparative study. J Natl Cancer Inst. 1975 Aug;55(2):281-4. PubMed | Google Scholar
- Akang EEU. Epidemiology of cancer in Ibadan: tumours in childhood. Arch Ib Med. 2000;1(2):9-11. PubMed | Google Scholar
- Rosemberg S, Fujiwara D. Epidemiology of pediatric tumors of the nervous system according to the WHO 2000 classification: a report of 1,195 cases from a single institution. Childs Nerv Syst ChNS Off J Int Soc Pediatr Neurosurg. 2005 Nov;21(11):940-4. PubMed | Google Scholar
- Scotting PJ, Walker DA, Perilongo G. Childhood solid tumours: a developmental disorder. Nat Rev Cancer. 2005 Jun;5(6):481-8. PubMed | Google Scholar
- Ojesina AI, Akang EEU, Ojemakinde KO. Decline in the frequency of Burkitt's lymphoma relative to other childhood malignancies in Ibadan, Nigeria. Ann Trop Paediatr. 2002 Jun;22(2):159-63. PubMed | Google Scholar
- Idowu O, Akang EEU, Malomo A. Symptomatic primary intracranial neoplasms in Nigeria, West Africa. J Neurol Sci Turk. 2007;24(3):212-8. PubMed | Google Scholar
- Louis DN, Ohgaki H, Wiestler OD, Cavenee WK, Burger PC, Jouvet A et al. The 2007 WHO classification of tumours of the central nervous system. Acta Neuropathol (Berl). 2007;114(2):97-109. PubMed | Google Scholar
- Parkin D, Kramarova E, Draper G, Masuyer E, Michaelis
J, Neglia J. International incidence of childhood cancer,vol
II. IARC scientific publication 144. Lyon; 1998. Google
- Aghadiuno PU, Adeloye A, Olumide AA, Nottidge VA. Intracranial neoplasms in children in Ibadan, Nigeria. Childs Nerv Syst. 1985;1(1):39-44. PubMed | Google Scholar
- Ogunbiyi J, Fabowale A, Ladipo A. Cancer incidence and Top ten cancers in eleven local governments in Ibadan and its environs, 2004-2008: Ibadan Cancer Registry, Nigeria. Technical report. 2010. PubMed | Google Scholar
- Olasode BJ, Shokunbi MT, Aghadiuno PU. Intracranial neoplasms in Ibadan, Nigeria. East Afr Med J. 2000 Jan;77(1):4-8. PubMed | Google Scholar
- Peris-Bonet R, Martínez-García C, Lacour B, Petrovich S, Giner-Ripoll B, Navajas A et al. Childhood central nervous system tumours--incidence and survival in Europe (1978-1997): report from Automated Childhood Cancer Information System project. Eur J Cancer. 2006 Sep;42(13):2064-80. PubMed | Google Scholar
- Kaatsch P, Rickert CH, Kühl J, Schüz J, Michaelis J. Population-based epidemiologic data on brain tumors in German children. Cancer. 2001 Dec 15;92(12):3155-64. PubMed | Google Scholar
- Zhou D, Zhang Y, Liu H, Luo S, Luo L, Dai K. Epidemiology of nervous system tumors in children: a survey of 1,485 cases in Beijing Tiantan Hospital from 2001 to 2005. Pediatr Neurosurg. 2008;44(2):97-103. PubMed | Google Scholar
- Asirvatham JR, Deepti AN, Chyne R, Prasad MSN, Chacko AG, Rajshekhar V et al. Pediatric tumors of the central nervous system: a retrospective study of 1,043 cases from a tertiary care center in South India. Childs Nerv Syst. 2011 Aug;27(8):1257-63. PubMed | Google Scholar
- Mehrazin M, Yavari P. Morphological pattern and frequency of intracranial tumors in children. Childs Nerv Syst. 2007 Feb;23(2):157-62. PubMed | Google Scholar
- Makino K, Nakamura H, Yano S, Kuratsu J-I, Kumamoto Brain Tumor Group. Population-based epidemiological study of primary intracranial tumors in childhood. Childs Nerv Syst. 2010 Aug;26(8):1029-34. PubMed | Google Scholar
- Jain A, Sharma MC, Suri V, Kale SS, Mahapatra AK, Tatke M et al. Spectrum of pediatric brain tumors in India: a multi-institutional study. Neurol India. 2011 Apr;59(2):208-11. PubMed | Google Scholar
- Pinho RS, Andreoni S, Silva NS, Cappellano AM, Masruha MR, Cavalheiro S et al. Pediatric central nervous system tumors: a single-center experience from 1989 to 2009. J Pediatr Hematol Oncol. 2011 Dec;33(8):605-9. PubMed | Google Scholar
- Ahmed N, Bhurgri Y, Sadiq S, Shakoor KA. Pediatric brain tumours at a tertiary care hospital in Karachi. Asian Pac J Cancer Prev. 2007 Sep;8(3):399-404. PubMed | Google Scholar
- Cho K-T, Wang K-C, Kim S-K, Shin S-H, Chi JG, Cho B-K. Pediatric brain tumors: statistics of SNUH, Korea (1959-2000). Childs Nerv Syst. 2002 Feb;18(1-2):30-7. PubMed | Google Scholar
- Nasir S, Jamila B, Khaleeq S. A retrospective study of primary brain tumors in children under 14 years of age at PIMS, Islamabad. Asian Pac J Cancer Prev. 2010;11(5):1225-7. PubMed | Google Scholar