Objective and importance: Necrotizing sarcoid granuloma (NSG) has been recognized as a histological variant of sarcoidosis. Two cases of neurosarcoidosis (NS) with NSG with concomitant systemic disease have been described previously. We present an unusual case of primary NS-NSG that resembled an en plaque cranial base meningioma.
Clinical presentation: A 51-year-old man presented with a 3-month history of progressive left visual deterioration and proptosis. Brain magnetic resonance imaging demonstrated a large cranial base lesion occupying the left anterior clinoid process and sphenoid wing, extending to the left frontotemporal convexity. A second dura-based lesion was observed in the right parietal convexity. Both lesions enhanced homogeneously after administration of intravenous contrast medium. Magnetic resonance imaging characteristics were consistent with a typical clinoidal meningioma with an en plaque extension laterally.
Intervention: A left frontotemporal craniotomy with extradural removal of the anterior clinoid process was performed. When the dura was opened, a red fibrous mass was identified. Intraoperative histological analysis revealed the presence of necrotizing and noncaseating granulomas. Postoperatively, cerebrospinal fluid, erythrocyte sedimentation rate, C-reactive protein, and serum and cerebrospinal fluid angiotensin-converting enzyme values were normal. The search for acid-fast bacilli or fungi was negative. A diagnosis of primary NS-NSG was made. The patient began long-term high-dose corticosteroid therapy. One and a half years after surgery, his vision had improved significantly and the lesions were stable as revealed by magnetic resonance imaging.
Conclusion: The first case of primary NS-NSG in the absence of systemic sarcoidosis is reported. NS should be included in the differential diagnosis of dura-based lesions resembling meningioma.