Two cases of meningocele and meningoencephalocele in Jeju native pigs

Abstract

BackgroundMeningocele and meningoencephalocele of the skull are congenital deformities. Various species, such as pigs, dogs, and cats, are susceptible to congenital meningocele and meningoencephalocele and the incidence is higher in large white and landrace pigs.Case presentationIn this study, swelling was observed in the fontanel areas of the median planes of the skull cap in two female piglets of the same litter. Gross clinical examination, neurological examination, computed tomography (CT), and magnetic resonance imaging (MRI) were conducted on the symptomatic piglets. The gross clinical and neurological examinations revealed no specific findings, except for the swellings. According to the CT results, the length of the defect on the sagittal section of the skull was 4.7 mm in case 1 and 20.62 mm in case 2. Connected flow between the skull swellings and the cerebrospinal fluid (CSF) of the lateral ventricles was observed, and partial herniation was identified in case 2. On MRI, CSF with high T2 signals was identified in the arachnoid spaces between the cerebrum and the cerebellum in the two cases, which is consistent with intracranial hypertension. The size of the swelling formed in the parietal bones was 1.6 × 1.1 × 1.8 cm3 (case 1) and 1.2 × 1.38 × 1.7 cm3 (case 2). The increase in intracranial pressure was more obvious in case 2 than in case 1, and was accompanied by posterior displacements of the mesencephalon and cerebellum.ConclusionsCase 1 was diagnosed as meningocele resulting from meningeal herniation and case 2 was diagnosed as meningoencephalocele caused by brain tissue herniation.

A case of cranium bifidum with meningocele in Ayrshire calf

“…A number of congenital malformations have been reported in cattle and other domestic animal species with their development associated with either or a combination of hereditary and environmental factors [9, 12, 13, 15–17]. In meningocele or encephalomeningocele, the prime morphogenetic event that leads to the development of bone defects through which the meninges protrude, alone or together with neural tissue, has been traced to the focal failure of neural tube closure during fetal development [12, 14, 15].…”

“…Craniomeningocele can be hereditary as has been reported in a number of domestic animals including cattle, sheep and pigs [11–13]. Environmental factors linked to the development of this condition are numerous, including chemical agents, such as griseofulvin when administered during pregnancy [11–13, 18].…”

“…Cranial bifidum is one of the NTD that manifests as a focal bone defect in the cranium usually with protrusion of meninges to form a CSF-filled sac-like swelling called meningocele. In some instances, the protrusion may also include brain tissue thus called encephalomeningocele [10–13]. The morphogenesis of these bone defects is not simply due to defective ossification but have instead been reported to depend on primary neural tube defect whereby, focal neural tube dehiscence from embryonic ectoderm fails leading to a focal failure in the development of skeletal encasement [13–15].…”

“…In some instances, the protrusion may also include brain tissue thus called encephalomeningocele [10–13]. The morphogenesis of these bone defects is not simply due to defective ossification but have instead been reported to depend on primary neural tube defect whereby, focal neural tube dehiscence from embryonic ectoderm fails leading to a focal failure in the development of skeletal encasement [13–15]. Either or both the genetic and environmental factors have been associated with the development of these congenital defects [11, 14–16].…”

Clinical features, imaging characteristics, and long-term outcome of dogs with cranial meningocele or meningoencephalocele

“…Congenital MCs and MECs have been reported in humans and various domestic animals. 15,16 A hereditary predisposition has been shown in Burmese cats, 16 but teratogenic factors and nutritional deficiencies may play a role in the development of such malformations. 17,18 Based on the small number of cases collected throughout Europe in this study, it appears to be a sporadically occurring disease, that might be underdiagnosed because diagnosis requires advanced imaging and some dogs may not have any neurologic signs, as occurred in the dog diagnosed with lymphoma and an incidental MEC.…”