Acute infarct of the corpus callosum presenting as alien hand syndrome: evidence of diffusion weighted imaging and magnetic resonance angiography

In this report, we present a patient with a mixed types of AHS coexistence secondary to the corpus callosum infarction, including a motor type of AHS by intermanual conflict (callosal type AHS) and a sensory type of AHS by alien hand and left hemianesthesia (posterior AHS).Our case may contribute to the early recognition of AHS and to explore the abnormal neural mechanism of AHS. To our knowledge, rare reports have ever documented such mixed AHS coexisting secondary to the callosal lesion, based on advanced neuroimaging methods as in our case.Alien hand syndrome (AHS) is a rare clinical syndrome, characterized by involuntary, uncontrollable and purposeless movements of one upper limb, and the patient denies ownership of the limb when touching it without visual guidance [1]. Such movements are aimless and differentiable from choreic and athetotic movements [2]. AHS is usually considered as a type of interhemispheric disconnection syndrome resulting from several lesions involving supplementary motor area, corpus callosum, medial frontal cortex, frontal, posterior parietal [3], or thalamus [4]. However, the neural mechanisms of AHS have remained controversial. Here, in this report, we describe a recent case of mixed types of AHS secondary to the infarction of the corpus callosum. Examinations of 3-Tesla magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) were used to assist early diagnosis of such a callosal infarct and to identify the abnormal neural processes of AHS. We briefly discuss the complex varieties of AHS, their anatomic substrates and the underlying neural mechanisms. To our knowledge, rare reports have documented such mixed types of AHS coexistence secondary to the corpus callosum infarction based on MRI, as reported in our case.A 71-year-old right-handed woman was admitted to our hospital because of urgent onset of paraphasia and slight weakness of her left hand for 13 days. The patient had a 20-year history of hypertension, coronary