[Immunohistochemical expression of progesterone receptor in relationship with histological grade and risk of relapses in intracranial meningiomas].

Introduction: Meningiomas are frequent primary neoplasms of the central nervous system, usually benign and susceptible to healing through surgery. The histological grade of the WHO and the extension of the initial surgical resection are determining prognostic factors in these tumors. Nevertheless, a recurrence rate close to 20 % in benign meningiomas completely diseccated arises the need of considering new prognostic factors.

Methods: A total of 93 cases were selected for the immunohistochemical study of the progesterone receptor (PR) in relation to the histological grade and the risk of recurrencies in meningiomas.

Results: Though the immunohistochemical labelling index (LI) of the PR decreased with the progression of the histological grade (means of 27.37 % for grade I, 17.89% for grade II, and 13.50% for grade III), such correlation was not statistically significant and the cut off estimated in 20% was not satisfactory to discriminate among benign meningiomas (grade I) and non benign (grades II-III) due to its poor sensitivity (56.10%) and positive predictive value (56.10 %). The comparison of the LI of the PR among non recurrent meningiomas (36.35 %) and recurrent (22.10%) was neither statistically significant, but permitted to establish a useful cut off of 40% (LI >40% in 13/23 non recurrent tumors and <40% in 19/23 recurrent tumors) with a sensitivity of 82.61% and a positive predictive value of 65.52%.

Conclusion: The LI of the PR is apparently not related to the histological grade of the meningiomas, but is significantly smaller in recurrent meningiomas. A meningioma with a LI of the PR less than 40 % suggests the risk of recurrences.