PROGESTERONE RECEPTOR EXPRESSION AND Ki-67 LABELLING INDEX OF MENINGIOMAS IN LAGOS UNIVERSITY TEACHING HOSPITAL: A 10 YEAR RETROSPECTIVE STUDY (2005-2014)

Abstract

Background: Meningiomas are the commonest primary central nervous system (CNS)
tumours in South Western Nigeria and are associated with significant morbidity and
mortality due to its location within the intracranial cavity. Even when completely excised,
meningiomas have a tendency to recur, and recurrence is associated with reoperations and
significantly shortened survival. Histopathologic parameters such as the WHO grade,
progesterone receptor (PR) expression and Ki-67 labelling index are predictive for
recurrence and are useful for individualizing management and treatment.
Aims and Objectives: The aim of this study was to determine the PR expression and Ki-67
labeling index of meningiomas received in the department of Anatomic and Molecular
Pathology, Lagos University Teaching Hospital from 2005 till 2014 with a view to
correlating the histologic predictive and prognostic factors with one another.
Materials and Methods: Slides of cases diagnosed as meningiomas received during the
study period were retrieved and reviewed. These were categorized into their respective
histologic subtypes and WHO grades. Immunohistochemistry for PR and Ki-67 were
performed on selected blocks. The data obtained was analyzed using SPSS22.
Results: Meningioma was the commonest primary CNS tumour seen accounting for 81 of
197 (41.1%) cases. There was a marked female predominance (male: female of 1:3.8) and
the peak age of occurrence was the 4th decade. Most cases were WHO grade I (86.1%)
tumours and of transitional histologic subtype (31.8%). PR immunoreactive score (IRS) and
Ki67 index varied widely within WHO grade I tumours and overlapped considerably with
values of WHO grade II tumours. There was a statistically significant reduction in the PR
2
score with increasing WHO grade (p=0.000). Ki-67 expression increased with increasing
WHO grade (p=0.000). An inverse correlation was found between ki67 index and PR score
(R= -0.7371).
Conclusion: Meningiomas in Lagos show a marked female predilection and occur much
earlier than cases in the western world. The WHO grades are heterogenous as pertains to
Ki67 and PR score with considerable overlap between grade I and II tumours. Ki67 and PR
score therefore help identify patients at higher risk of recurrence even within the same WHO
group.