Abstract
RATIONALE: Meningiomas are mostly benign brain tumors with minimal malignant cases. Anaplastic meningioma has malignant morphological characteristics and a World Health Organization grade of III. PATIENT CONCERNS: The present study reports a case of an occipital meningioma in a patient who initially chose observation and follow-up after diagnosis. The patient ultimately underwent surgery due to the enlargement of the tumor and the development of visual field defects after a decade of imaging follow-up. The postoperative pathology slides indicated the presence of an anaplastic meningioma (World Health Organization-grade III). DIAGNOSES: The patient's diagnosis was established through cranial magnetic resonance imaging, which revealed an irregular mixed mass in the right occipital region with isointense T1 and hypointense T2 signal, irregular lobulation, and a maximum diameter of approximately 5.4 cm. Heterogenous enhancement was observed in the contrast-enhanced scan. INTERVENTIONS: The patient opted for surgical intervention to remove the tumor, and the pathology slides of the tumor sample confirmed the diagnosis of anaplastic meningioma. The patient also received radiotherapy (40Gy/15fr). OUTCOMES: No recurrence was observed during the 9-month follow-up. LESSONS: This case highlights the potential for low-grade meningiomas to undergo malignant transformation, particularly in the presence of irregular lobulation, peritumoral brain edema, and heterogeneous enhancement on contrast-enhanced scans. Total excision (Simpson grade I) is the preferred treatment option, and long-term imaging follow-up is recommended.