Rare primary angiitis of the central nervous system affecting the clivus: A case report.

Diseases involving the clivus are highly variable, and the incidence of each disease is rare. Primary central nervous system vasculitis (PACNS) is a rare disease with very heterogeneous clinical manifestations, its diagnosis is often challenging, and histopathology is the gold standard. We report a patient with PACNS of the clivus, with a 1-month history of headache and diplopia, who was misdiagnosed as having a tumor of the clivus during prior treatment, due to computed tomography findings of clivus occupation and bone destruction. Endoscopic resection of the nasal clivus lesions was performed. Pathological examination revealed a small abscess with hemorrhage, necrosis, extensive infiltration of lymphocytes and plasma cells, and granulation tissue scar formation. After histopathological examination, the diagnosis was confirmed, and oral glucocorticoid and cyclophosphamide were commenced. This study is the first to report a tumor-like PACNS, that occurs in the clivus, thereby enriching our understanding of PACNS.