Objective: To investigate the clinicopathologic and immunohistochemical features of secretory meningiomas.
Methods: Nine secretory meningiomas were examined. From each specimen, sections were cut and stained with hematoxylin-eosin, periodic acid-Schiff (PAS) stain, and periodic acid-Schiff stain with diatase(PAS-D ). Immunohistochemical markers including oestrogen receptor (ER), progesterone receptor (PR), carcinoembryonic antigen (CEA), cytokeratin (CK), epithelial membrane antigen (EMA), and MIB-1 were detected with streptavidin peroxidase (SP) immunohistochemical staining methods. One case was observed by electron microscopy (EM).
Results: The 9 secretory meningiomas were located at sphenoid ridge, left parietal lobe or frontal lobe. Severe peritumoral edema was observed in 5 cases. Seven cases were followed up for 6 to 88 months; none of them showed evidence of recurrence. Histologically, the conspicuous feature was the eosinophilic inclusions. The finding of pericytic proliferation on examination was helpful to making a diagnosis. In all 9 cases, the tumor cells were positive for PR, but in 6 cases the inclusions were negative. ER was negative in 8 cases. CEA,CK, EMA expressed in the inclusions and the surrounding cells in 7 cases. In 1 case the positive rate for MIB-1 was 5%, but in the other 8 cases the positive rates were not more than 2%. The intercellular lumens and intracellular mucosa were observed under EM.
Conclusion: Secretory meningioma is a rare subtype of meningioma that shows glandular epithelium differentiation. It is a meningioma of the low-risk type in terms of incidence, recurrence and prognosis.