Magnetic Resonance Imaging Features of Lissencephaly in 2 Lhasa Apsos

Abstract

Two Lhasa Apsos were diagnosed with lissencephaly based on MR imaging and clinical findings. Histologic confirmation of the diagnosis was obtained in one dog. The MR imaging appearance of the brain in 2 Lhasa Apsos with lissencephaly was of a smooth cerebral surface and a thick neocortex with an absence of the corona radiata. This correlated very well with the histopathologic findings in the dog. Our findings, together with the histopathologic features reported previously, are most consistent with Lhasa Apsos having the canine equivalent of human classical lissencephaly. MR is the imaging modality of choice for antemortem diagnosis of canine lissencephaly.

Clinical and MRI Findings of Lissencephaly in a Mixed Breed Dog

“…In veterinary medicine, lissencephaly has been reported in only 5 dogs, all of which were Lhasa Apsos [5,14,18]. The etiologic mechanism for dog lissencephaly is uncertain; however, it is assumed to be associated with genetic disease rather than teratogenic disease because most of the cases that have been reported to date occurred in Lhasa Apso dogs [5].…”

“…In dogs, lissencephaly predominantly results in signs of forebrain disease such as seizures, visual deficits and behavioral abnormalities including difficulty in training [5,14,18]. Histopathologic findings of the lissencephalic brain revealed a lack of gyral development accompanied by a lack of corona radiata in those affected areas, as well as a thickening of the neocortex [5,14,18].…”

“…Histopathologic findings of the lissencephalic brain revealed a lack of gyral development accompanied by a lack of corona radiata in those affected areas, as well as a thickening of the neocortex [5,14,18]. In one report, magnetic resonance imaging (MRI) showed a smooth cerebral surface and a thick neocortex with an absence of the corona radiata [14]. Thus, MRI is considered as the method of choice for antemortem diagnosis of lissencephaly.…”

“…Lissencephaly in humans results in mental retardation, spastic quadriparesis, spastic paraparesis, focal deficits, hypotonia, cerebellar symptoms, muscular hypotonia and seizure [10]. In dogs, lissencephaly primarily results in signs of forebrain disease such as seizures, visual deficits, and behavioral abnormalities [5,14]. In a previous report, the gait and postural defects were mild in dogs when compared with those in humans with lissencephaly [5].…”

“…In this case, the dog had normal postural reactions. When compared with humans, the differences in clinical signs are likely because there is less dependence on the cortex in dogs than in humans [14].…”