Association of different uncus lesions on magnetic resonance imaging with epilepsy

Abstract

Objective: Uncus is the hook-like most anteromedial portion of the parahippocampal gyrus and is a part of the limbic system. It is the only gyrus, together with the amygdala, that contains nuclei and is associated with seizures accompanied by olfactory hallucinations. The aim of this study is to examine the relationship between different uncus lesions detected by magnetic resonance imaging (MRI) and epilepsy/seizures. Method: 33 patients with unilateral or bilateral uncus lesions on MRI obtained between March 2008 through May 2014 were enrolled in the study. MR images and clinical charts of patients were retrospectively investigated for MRI findings and presence of epilepsy/seizures. Results: Bilateral uncus involvement was observed in herpes encephalitis (n=5), autoimmune limbic encephalitis (n=2), mesial temporal sclerosis (n=3), metastasis (n=1) and Rasmussen encephalitis (n=1), whereas unilateral involvement of the uncus was seen in glial tumors (n=4), metastases (n=4), mesial temporal sclerosis (n=4), cavernous angioma (n=2), dysembryoplastic neuroepithelial tumor (DNET, n=5), herpes encephalitis (n=1), and autoimmune limbic encephalitis (n=1). Epilepsy/seizures were present in two-thirds of patients. However, none of the 5 patients with a metastatic uncus lesion showed epilepsy/seizures. Conclusions: Many uncus pathologies can be detected by MRI and most of them are associated with epilepsy.