This study is designed to investigate the safety, diagnostic performance, and clinical usefulness of Gleolan for the real time detection and visualization of meningiomas during tumor resection surgery. Potential patients who sign informed consent will be screened for eligibility before receiving an oral solution of Gleolan 3 hours prior to anesthesia prior to undergoing surgery for meningioma resection. Participants will be evaluated up to 6 weeks post procedure for a safety assessment. Patients with suspected newly diagnosed or recurrent meningioma of all histological grades who are indicated for, and have a planned resection, will be screened for enrollment Patients from within Penn Medicine practices will be approached to participate in this trial.

You may be eligible for this study if you meet the following criteria:

• Conditions: meningioma
• Age: Between 18 Years - 99 Years
• Gender: All