Progesterone receptor expression and Ki-67 labelling index of meningiomas in the Lagos university teaching hospital.

Background: Meningioma in Nigeria has been poorly studied. Its location within the intracranial cavity is associated with significant morbidity and mortality. Even when completely excised, it has a tendency to recur and this is associated with repeat operations and shortened survival. The World Health Organization (WHO) grade, progesterone receptor (PR) expression and Ki-67 index are predictive for recurrence and are, therefore, useful for individualised management. The aim of this study was therefore to determine the PR expression and Ki-67 index of meningiomas received in our institution.

Materials and Methods: A retrospective review of the forms, slides and results of meningiomas received at the Department of Anatomic and Molecular Pathology, Lagos University Teaching Hospital, from January 2005 to December 2014, was undertaken. Immunohistochemistry for PR and Ki-67 was performed and correlated with other histologic parameters.

Results: Meningioma was the most common primary CNS tumour seen. The male-to-female ratio was 1:3.8; with a peak in the 4th decade. Most cases were WHO Grade I tumours (86.1%) and transitional histologic subtype (31.8%). PR immunoreactive score and Ki-67 index varied widely within WHO Grade I tumours and overlapped considerably with Grade II tumours. PR expression reduced and Ki-67 index increased with increasing WHO grade (P = 0.000). A moderate inverse correlation was found between Ki-67 index and PR score (R = -0.7371).

Conclusion: The peak age of meningioma in our patients is five decades earlier than in western populations. Although PR expression reduces and Ki-67 index increases with increasing grade, there is nevertheless a considerable overlap. Management therefore must be individualised.