Neural Tube Dysraphism: Review of Cutaneous Markers and Imaging

Abstract

Neural tube dysraphisms are congenital anomalies resulting from impaired formation of structures along the craniospinal axis during central nervous system development. When these malformations are large or lack a skin covering, they are easily recognized, whereas smaller or skin-covered malformations may not be readily apparent. Due to the intimate embryologic origin of the skin and nervous system, these occult malformations are often heralded by associated cutaneous abnormalities. In this article, the common clinical presentations and cutaneous markers of craniospinal dysraphism are reviewed, along with the recommended imaging modalities.

Overview on neural tube defects: From development to physical characteristics

“…The macroscopic aspect of the encephalocele is a round, soft, compressible nodule with subscalp localization (Figure ; Gao, Massimi, Rogerio, Raybaud, & Di Rocco, ). The mass may appear solid or cystic according to the content of the herniation, and it is generally covered by alopecic skin that could be surrounded by a ring of hair determining the so called “hair collar signs” (Gao et al, ), although sometimes hypertrichosis may be present over the lesion (Sewell, Chiu, & Drolet, ). Sometimes the surface of encephalocele appears bluish, translucent or glistening, and capillary malformations are detectable (Sewell et al, )…”

“…As a result of its patent intracranial communication, encephaloceles modify its dimension (enlargement/reduction) with the modification of intracranial pressure: it enlarges during increase of pressure such as during Valsalva maneuver (Sewell et al, ) including crying and suction.…”

“…The presence of cutaneous stigmata of the low back may be the only signs of occult spina bifida. Cutaneous markers include nevi, lumps, depigmented region, subcutaneous lipomas, capillary hemangiomas, hair tufts (localized hypetricosis), and dermal sinus tract (Hertzler et al, ; Sewell et al, ). Structural abnormalities may also been detected such as an asymmetrical gluteal cleft, scoliosis, and leg length discrepancy.…”

“…In fact, by ultrasound, lipomas typically appear as echogenic masses (Ghi et al, ) much like a meningocele. Postnatally, high‐resolution ultrasound may be employed until the sixth month of life, before the ossification of the vertebral body, but the sensitivity is low, especially in cases of a subcutaneous mass (Sewell et al, ). The more appropriate diagnostic technique is magnetic resonance, but this procedure is limited by its cost, availability, and the need for sedation for many children.…”

“…During the intrauterine life, the spinal cord grows slower than the spinal column. The caudal spinal cord (also called conus medullaris) reaches its normal level only after birth, and the symptoms may start through the extrauterine life when the cord is insulted (Sewell et al, ). Sometimes this occurs in childhood, other times this occurs later in life, in case of thickening of filum terminale (increased fibrosis leading to progressive loss of elasticity), increased physical activity, development of spinal stenosis or occurrence of lumbar trauma (Hertzler et al, ).…”