Primary angiitis of the CNS (PACNS), granulomatous angiitis of the nervous system (GANS), isolated CNS vasculitis (ICNSV), isolated angiitis of the CNS (IACNS).

Angiitis of the central nervous system is defined by inflammation of the medium-sized and small vessels that supply the CNS. It may occur secondary to a connective disease, in particular systemic lupus erythematosus or Sjögren's syndrome, or in association with an infection, malignancy, or drugs, where it is often difficult to differentiate angiopathy from true angiitis. Angiitis of the central nervous system may also occur as a manifestation of a primary systemic vasculitis or as a primary angiitis of the CNS whereby patients have clinical involvement isolated to the CNS and there are minimal to no signs of systemic vasculitis. Two variants of primary angiitis of the CNS have been suggested: granulomatous angiitis of the CNS (GACNS) and benign angiitis of the CNS (BACNS). BACNS has a monophasic course and...