Area Postrema Syndrome: A Rare Feature of Chronic Lymphocytic Inflammation With Pontine Perivascular Enhancement Responsive to Steroids.

The area postrema syndrome (APS) is a unique diagnostic criterion for neuromyelitis optica spectrum disorders (NMOSD). However, APS has rarely been reported in cases of chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS). A 36-year-old woman presented with APS and clinical features of diffuse central nervous system involvement during the early stage of the disease. Owing to the absence of serum aquaporin 4 antibodies, she was initially misdiagnosed as a case of seronegative NMOSD. However, the distinct neuroimaging characteristics [symmetrical small punctuate gadolinium enhancing lesions (pepper-like)], typical clinical/radiological relapse, and intense steroid-dependence in this case, prompted us to correct the diagnosis as probable CLIPPERS. To prevent relapse, long-term oral steroids and an immunosuppressive agent were administered. CLIPPERS may present as APS, and should be considered in the differential diagnosis of NMOSD.