Unveiling primary intracranial eosinophilic angiocentric fibrosis: A rare case report and diagnostic dilemmas

Abstract

Eosinophilic angiocentric fibrosis (EAF) is a rare, benign fibroinflammatory condition primarily affecting the sinonasal and upper respiratory tract, with a few cases reported beyond these regions. Primary intracranial EAF is rare. To date, only one case of intracranial EAF has been reported; ours is the second. This case report presents a case of EAF in a 55‐year‐old man, initially misdiagnosed as meningioma based on clinical and radiological features. The patient complained of a persistent dull headache for six months without associated neurological symptoms. Brain magnetic resonance imaging revealed a dural‐based lesion with characteristics suggestive of meningioma. However, histopathological examination post‐surgical resection revealed a nodular vascular lesion with concentric angiocentric fibrosis, a distinctive onion skin pattern, and an inflammatory infiltrate rich in eosinophils, plasma cells, and histiocytes. Immunohistochemistry ruled out IgG4‐related disease, and other systemic disorders were ruled out based on combined clinical and histological features. This case underscores the need for considering EAF in the differential diagnosis of dural‐based lesions. Awareness of its potential mimicking of meningioma is crucial for accurate diagnosis and appropriate management, emphasizing the importance of histopathological examination in challenging cases.