Meningioma with transcalvarial extension and malignant transformation presenting as a frontoparietal scalp swelling

Abstract

Introduction: Meningiomas are the slow-growing and most common benign CNS tumors. They usually behave as expansive lesions, compressing the brain tissue, but some are invasive with malignant potential, causing direct invasion of the neighboring structures with extracranial extension. Malignant meningioma (MM) is rare and accounts for about 1% of all intracranial meningiomas. Computed tomography (CT) and MRI imaging are useful diagnostic tools for an accurate diagnosis. However, biopsy or resection is the only method to definitively confirm the diagnosis through histopathologic analysis and revealing the grade of meningiomas. Case presentation: A 79-year-old male presented to our neurosurgery outpatient clinic 5 years ago, complaining of a left frontal swelling. His brain MRI revealed a mass in the frontal region of the brain with minimal extracranial transcalvarial extension into the frontoparietal scalp region. During the 5 years follow up no significant progression was observed in the mass size and extension. In July 2020, he complained of speech disorder, indicating an increase in mass size and transcalvarial extension as documented by brain imaging. Surgical intervention and mass resection was done. The pathologic exam revealed a meningioma with malignant transformation. Discussion: Most of the meningiomas are benign tumors and consider grade 1. However, 1–3% of these lesions are known as malignant meningiomas, which have a high recurrence and mortality rate even after the surgery. Conclusion: Intracranial malignant meningioma with transcalvarial extension is an exceedingly rare entity. Computed tomography and MRI imaging are useful diagnostic tools for an accurate diagnosis. However, biopsy or resection is the only method to definitively confirm the diagnosis, through histopathologic analysis and revealing the grade of meningiomas. Complete surgical resection is the mainstay of the treatment and preoperative embolization is a proven ancillary management technique for intracranial meningiomas, leading to decreased operative blood loss, increased visualization of the operative field, and better resection of the tumor. Highlights