Rare case of dual lesion: intraosseous microcystic meningioma – case report and review of literature

Introduction/background Intraosseous microcystic meningioma is an exceptionally rare clinical entity, representing a diagnostic challenge due to its atypical osteolytic presentation and specific histological features. This case is unique because it occurs in a 43-year-old patient—younger than the reported median age—and highlights specific MRI "shine-through" effects that can assist in preoperative differentiation from aggressive bone malignancies. Case presentation A 43-year-old woman presented with a six-month history of intermittent parietal pain. Imaging revealed a 1.9 × 0.9 cm osteolytic defect in the right frontal bone with internal septations. MRI showed T2-hyperintensity and heterogeneous enhancement, but no restricted diffusion on ADC maps. The patient underwent gross total resection with dural repair and titanium mesh reconstruction. Histopathology confirmed a WHO Grade I microcystic meningioma, positive for EMA, SSTR2, and D2-40. Conclusion The main "take-away" is that intraosseous microcystic meningioma should be considered in the differential diagnosis of solitary osteolytic skull lesions. Multi-parametric MRI, specifically the absence of restricted diffusion despite high DWI signal (T2 shine-through), is a key indicator of this benign, fluid-rich subtype.