Background: Intraosseous meningioma are rare entities. There surgical management are often challenging. One-step customized cranioplasty can be a good solution to treat them. Case description: The authors report the case of a 54-year-old woman with a consequent frontal intraosseous meningioma invading the superior sagittal sinus. The patient only suffered from local pain and cosmetic damage. A complete resection was scheduled with a one-step reconstruction of the frontal bone by a polyetheretherketone (PEEK) specific implant. This implant was computer-assisted designed and manufactured and verified by the surgeon before the intervention. During surgery, the resection was guided by a computer designed resection template and by the classic neuronavigation system. Cranioplasty has been considered optimal intraoperatively by surgeons. The patient, a few weeks after surgery, underwent a subcutaneous fluid collection, rapidly resolutive with a circumferential pressure bandage. Six months after surgery, the patient considered the surgery a success with a very good cosmetic result and a total regression of her local pain. Conclusion: One-step computer-assisted cranioplasty is a safe and effective procedure for large skull defects. PEEK specific implant for cranioplasty offer advantages compared to other materials that will be discussed under the scope of the one-step reconstruction.