Tumor-Like Presentation of Primary Angiitis of the Central Nervous System.

Background And Purpose: We aimed to describe the clinical and imaging features of patients with tumor-like presentation of primary angiitis of the central nervous system.

Methods: We retrospectively analyzed 10 patients enrolled in the French primary angiitis of the central nervous system cohort, who initially presented tumor-like brain lesions and compared them with other patients within the cohort.

Results: The 10 patients with tumor-like presentation in the cohort were younger and had more seizures at diagnosis than the other 75 patients (median of 37 [30-48] years versus 46 [18-79] years; P=0.008; 9 [90%] with seizures versus 22 [29%], P<0.001; respectively). All 10 patients had a biopsy (stereotactic procedure in 7 and open-wedge surgery in 3). Histological findings suggestive of vasculitis were observed in 9 patients in whom conventional cerebral angiography and magnetic resonance angiography were negative. In the remaining patient, vascular imaging demonstrated diffuse bilateral large- and medium-sized vessel involvement (biopsy did not reveal vasculitis). All patients with tumor-like presentation received glucocorticoids, combined with cyclophosphamide in 9 cases. With a median follow-up of 27 (12-130) months, 5 (50%) patients relapsed, but achieved remission again after treatment intensification.

Conclusions: Patients with tumor-like presentation of primary angiitis of the central nervous system represent a subgroup characterized with mainly small-sized vessel disease that requires histological confirmation because vascular imaging is often normal. Although relapses are not uncommon, global outcomes are good under treatment with glucocorticoids and cyclophosphamide.