Segmental spinal dysgenesis (SSD) is a rare congenital spinal abnormality. A 28-year-old woman was referred at 21 week gestation for a fetal MRI following sonographic findings of bilateral talipes and possible spina bifida. A prenatal diagnosis of SSD was proposed. A post-mortem fetal imaging including X-ray survey, CT and MRI was done followed by a complete autopsy. The combined major findings included: Dysplastic vertebral body below L1, absence of L2-L4 segment, presence of L5 and five sacral vertebrae, posterior dislocation of the inferior spinal segment with severe canal narrowing; thin thoraco-lumbar spinal cord above the dislocation, severe at T11 level; histological dysplasia of the thinned segment of the spinal cord with normal caudal cord; anterior intradural neurenteric cyst and segmental agenesis of the anterior spinal artery. The cranial spinal cord showed no crossing over of the cortical spinal tracts.
The above findings represent the most characteristic features of SSD. SSD should be considered in the differential diagnosis of close spinal dysraphism. It may represent a disorder of the gastrulation during the third week of gestation, a developmental step regulated by multiple genes and signaling molecules. The etiology of SSD remains uncertain. To our knowledge, this is the first case diagnosed by prenatal MRI and with a neuropathological examination.
Learning Objectives:
This presentation will enable the learner
1. To define the major morphological characteristics of Segmental Spinal Dysgenesis.
2. To speculate on the pathogenesis of this rare disorder.
Conflictsof Interest:
None.
