Scanning electron microscopy of primary neurulation in chick embryos. A, The neural plate exists initially as a midline layer of pseudostratified columnar epithelium. B, The neural groove develops in the midline of the neuroectoderm and the neural folds begin to elevate. The cutaneous ectoderm is attached laterally to the neuroectoderm. C, The neural folds begin to converge toward each other. D, The neural folds have fused and the cutaneous ectoderm has separated to form a layer of intact skin overlying the neural tube. Reproduced with permission from Gilbert SF. Developmental Biology. 7th ed. Sunderland, MA: Sinauer Associates; 2003:394.
Cervical MMC. A, Lateral view showing full-thickness skin with violaceous apex and no cerebrospinal fluid leakage. B, Operative view demonstrating the thin stalk of tissue arising from a small fascial defect.
Spinal lipoma. A, Subcutaneous mass with overlying faint pink capillary malformation (NFS or “salmon patch”). B, An otherwise invisible spinal lipoma associated with an overlying pink NFS with indistinct borders. C, An otherwise invisible spinal lipoma associated with an overlying raised sacral infantile hemangioma having distinct borders. D, A PWS.
Lumbosacral DSTs. A, DST superiorly (arrow) with deviated gluteal cleft inferiorly. B, DST with surrounding infantile hemangioma. C, DST with skin appendage and hair in ostium. D, Subcutaneous dermoid.
Frontonasal DST. A, DST arising from the glabella. B, Sagittal T2-weighted MRI showing dermoid cyst (arrow) with tract extending through the anterior skull base at the level of the foramen cecum (arrowhead).
Atretic parietal encephaloceles. A, Scarified midline lesion with whorl of surrounding hair (or “horse collar”). B, Magnetic resonance venogram showing persistent falcine vein (arrowheads) and absence of straight sinus (arrow).