Tumour-like mass lesion: an under-recognised presentation of primary angiitis of the central nervous system

Objective: To describe the occurrence of mass lesions (ML) in primary angiitis of the central nervous system (PACNS) and assess the utility of diagnostic testing and treatment. Methods: We examined the case records of the Cleveland Clinic ( CC), Massachusetts General Hospital (MGH), and the English language medical literature, for biopsy-proven PACNS cases presenting as a solitary ML. Relevant clinical variables were extracted and analysed with JMP software. Results: We identified a total of 38 ML: eight of 202 (4.0%) patients with CC/MGH and 30 of 535 (5.6%) patients with PACNS identified from the medical literature. A higher percentage (13 of 45; 29%) was seen in the amyloid-related angiitis subset. Poorer outcomes were reported in the amyloid group, with five deaths. Of the non-amyloid group, better outcomes were seen in the group treated with corticosteroids and cyclophosphamide as compared with the group treated with corticosteroids alone. Conclusions: Although rare, PACNS should be considered in the differential diagnosis of ML; greater awareness of this manifestation may facilitate more prompt diagnosis and treatment. Biopsy evidence of angiitis is required for diagnosis; specimens should routinely be stained for amyloid. While excision of the lesion may be curative, aggressive immunosuppressive therapy is associated with favourable outcomes and may obviate the need for surgery.