A case of neuroacanthocytosis associated with mesial temporal sclerosis

Clinical History

A 43-year-old male patient presented with a history of recurrent seizures, movement disorder, dysphagia and progressive behavioural changes.

Imaging Findings

An MRI study of the brain was performed with 1.5 T MR including three orthogonal FSE T2-weighted, axial GRE, FLAIR and DWI sequences, and three orthogonal FSE T1-weighted sequences after Gadolinium-DTPA infusion. Perfusion (GRE EPI) and single voxel spectroscopy (SV TE 144 and 35) studies were also performed. MRI revealed bilateral caudate and putamina atrophy without signal intensity changes, with secondary dilatation of the anterior horn of the lateral ventricles. Apparent diffusion coefficient (ADC) values in the striatum bilaterally were increased. High resolution and volumetric sequences revealed left hippocampal mild atrophy and slight increased signal on T2-weighted and FLAIR. rCBV values, measured in the left hippocampus and in both caudate nuclei, were not significantly reduced. Proton spectra – recorded from two VOI containing left temporal uncus and ipsilateral caudate – demonstrated decreased peak of NAA, and myoinositol and choline peaks increased. No areas of abnormal contrast enhancement were found.

Discussion

Neuroacanthocytosis (NA) denotes a group of uncommon heterogeneous neurodegenerative disorders characterized by neurologic signs and symptoms associated with the presence of acanthocytes in the peripheral blood, in the absence of any lipid abnormality¹. There are many inherited cases but sporadic ones are also known. The inherited cases are mainly classified into autosomal recessive chorea-acanthocytosis and X-linked McLeod syndrome².
Mean age of onset in NA is about age 30 years. It runs a chronic progressive course and may lead to major disability within a few years or, rarely, to sudden unexplained death or death during epileptic seizures³. Epilepsy is observed in almost half of affected individuals and can be the initial manifestation⁴. It is usually manifested as grand mal seizures and is probably secondarily generalized, for example, from temporal lobe foci⁵.
Pathologically the most severely brain affected areas are the caudate nucleus and putamen and, to a lesser degree, the globus pallidus, thalamus, substantia nigra and anterior horns of the spinal cord⁶.
MRI is the modality of choice to image abnormalities of the basal ganglia in NA as it best shows, especially on sections in the coronal plane, the ipo-atrophy of the striata, particularly the caudate nucleus, with or without increased signal intensity on T2-weighted imaging⁸. In patients with NA 1H-Magnetic Resonance Spectroscopy (HMRS) analysis, recorded from single voxels containing putamen and globus pallidus, shows a significantly higher intensity of myoinositol and choline peaks⁷.
Post-mortem analysis reveal atrophy of the caudate, putamen, and to a lesser extent pallidus and substantia nigra. Histological examination shows marked neuronal loss and astrocytic gliosis, especially affecting the caudate^10,11.
Some authors describe also frontal lobe atrophy, cerebellar atrophy or a more generalized cerebral atrophy with dilatation of the anterior horns of the lateral ventricles^1,5,9.
Hippocampal sclerosis and atrophy are also seen and, when present, as in our case, they can be the cause of temporal lobe epilepsy^4,6. In these cases MRI typically shows atrophy and T2/FLAIR hyperintensity of the hippocampus⁵, best appreciated on the coronal plane. The nature of this association is yet to be clarified and it is important to consider that typical MRI findings, leading to the suspect of mesial temporal sclerosis, could be caused by seizure itself¹².
Thus, radiologist must be aware of this association in order to correctly identify the typical imaging features of NA in association, when present, to that of mesial temporal sclerosis.

Differential Diagnosis List

Final Diagnosis

Neuroacanthocytosis associated with left mesial temporal sclerosis.

URL:	https://www.eurorad.org/case/9393
DOI:	10.1594/EURORAD/CASE.9393
ISSN:	1563-4086