Rapid recurrence and malignant transformation of a benign meningioma after pregnancy: a case report.

We report rapid recurrence and malignant transformation of a benign meningioma during pregnancy in a young woman. A 30-year-old female meeted an operation of benign meningioma (WHO Grade I) before her pregnancy. No signs of recurrence were found in MRI two months before her pregnancy. Subsequent MRI was performed 6 months after her giving birth. MRI results showed a recurrent meningioma with a size of 45 × 49 × 32 mm. Reoperation was performed later, histopathological workup showed an atypical meningothelial meningioma(WHO Grade II) with a Ki-67 level of about 10% and a PR expression above 70%; no ER was observed. To our best knowledge, this is the first report of the rapid malignant transformation of a benign meningioma during pregnancy.