Unique features of pregnancy-related meningiomas: lessons learned from 148 reported cases and theoretical implications of a prolactin modulated pathogenesis.

Meningiomas are some of the most frequently encountered adult intracranial tumors. Dramatic flare ups in size may occasionally be observed during pregnancy, leading to complicated clinical scenarios, with profound effects and substantial risks for both the mother's and the fetus's well-being. Despite the fact that such changes have largely been attributed to progesterone-based mechanisms, recent studies have put this theory into question or defied it. In order to assess these particular tumors carefully and to try and clarify the pathophysiology of such pregnancy-related meningioma growth, an in-depth review of the pertinent literature was undertaken. Based on clinical, radiographic, and pathological data gathered from 148 reported cases, we have found several unique features characterizing these pregnancy-related meningiomas. The presence of such observed features was found to be of high statistical significance when compared to their expected prevalence in the general population and included the following: (1) parasellar location, (2) anterior circulation blood supply, (3) visual symptoms at presentation, (4) high rate of clear-cell and chordoid morphology. A hypothesis is developed that these features are related to hormonal influences of the pituitary gland, and we discuss that this may be due to elevated prolactin levels. We encourage further research to test this exciting new theory.