A case of pilocytic astrocytoma requiring tumor resection during pregnancy.

Low-grade glioma (LGG) is often encountered in relatively young individuals, including women of childbearing age. Notably, case series describing pregnant women with LGG have been reported in the literature. The present study reported a case of pilocytic astrocytoma (PA) requiring tumor resection during pregnancy. The patient had a history of γ-knife radiotherapy for a brainstem tumor 17 years previously. The histological diagnosis was unclear. The tumor had remained stable following radiosurgery for 17 years, including during her first pregnancy. However, rapid tumor growth around the fourth ventricle occurred at week 25 of her second pregnancy. Therefore, an urgent tumor resection was performed despite the pregnancy. Partial resection was performed since the tumor had infiltrated the brainstem. The histological diagnosis was PA. The residual tumor volume decreased gradually following the delivery. Immunostaining of the tumor for the expression of progesterone receptor revealed focal staining. It is possible that reproductive factors, including specific hormonal changes during pregnancy, affected the tumor growth. The present study described this rare case of PA, which exhibited rapid growth and required urgent surgery during pregnancy.