Autoimmune- or antibody-associated disorders of the central nervous system have become an emerging concept in neurology over the past decade. These disorders include a heterogeneous group of syndromes that include encephalitic syndromes associated with antibodies that target neuronal cell surface proteins. Autoimmune encephalitis is mediated by pathogenic antibodies that cause reversible effects on synaptic functions in neurons with relatively little neuronal death. Thus, early recognition and treatment of these syndromes are crucial, as prognosis of patients with these syndromes tends to be better, with substantial or complete recovery after immunotherapy and tumor treatment if present. The neuroimaging criterion required for the definite diagnosis of autoimmune limbic encephalitis consists of the presence of bilateral brain abnormalities on T2/FLAIR MRI highly restricted to the medial temporal lobes. In the absence of such radiological findings, FDG-PET imaging can be used to fulfil such criterion and thus facilitate early diagnosis, as FDG-PET might be more sensitive than MRI to reveal an increase in FGD uptake in otherwise normal-appearing medial temporal lobes. In this chapter, a case of anti-Contactin-associated protein-like 2 (Caspr2) limbic encephalitis is presented.