[The characteristics of the histological structure of parasagittal meningiomas and their effect on postoperative recurrence].

Among 506 parasagittal meningiomas, 3 histological types: typical, atypical, and anaplastic ones were identified, which differ in malignancy, as evidenced by varying incidence rates of postoperative recurrences in these groups, and amounted to 11, 34.7, and 100%, respectively. The likelihood of postoperative recurrences of parasagittal meningiomas are substantially affected by the histological structural features, such as nuclear polymorphism, dense cell foci, papillary structures, mitoses, lymphoid infiltrates, and necrotic foci. The presence of meningiomas of perivascular lymphoid infiltrates in the structure may be regarded as an indicator of the benign biological behavior of a tumor while that of lymphoid infiltration in the meningiomal stroma considerably enhances the likelihood of tumor recurrence and is a poor predictor.