The Absence of the Neuronal Component in Limited Dorsal Myeloschisis: A Case Report.

INTRODUCTION

The presence of neuroglial tissue is considered a hallmark in limited dorsal myeloschisis (LDM). However, several reports have indicated that the presence of neuroglial tissue in LDM cannot always be demonstrated. Here, we present such a case of LDM and provide an alternative hypothesis for lacking the neuronal component.

CASE DESCRIPTION: An antenatal LDM suspected neonate was born with a cystic skin lesion and membranous sac typical for membranous LDM. Three days postpartum the otherwise healthy infant underwent surgery, during which the stalk was resected and the spinal cord was untethered. Histopathologically, no neuroglial tissue could be determined. Noteworthy, S-100 staining revealed numerous peripheral nerves.

DISCUSSION: The current paradigm explains the absence of neuroglial tissue in resected stalks of LDM by indicating that it should be present in the unresected part, more proximal to the dorsal spinal cord. We hypothesize a different mechanism in which following reopening of the neural tube, mesodermal invasion causes a tight and persistent strand between the cutaneous- and neuroectoderm. Elongation of this mesodermal strand during embryological development allows for the formation of a mesenchymal stalk without the presence of neuroglial tissue. Hydrodynamic forces can cause fistulation of the poorly differentiated mesodermal tissue and subsequently lead to a saccular defect.