Slender Stalk with Combined Features of Saccular Limited Dorsal Myeloschisis and Congenital Dermal Sinus in a Neonate.

Limited dorsal myeloschisis (LDM) and congenital dermal sinus (CDS) originate from incomplete disjunction between the cutaneous and neural ectoderms. Some LDM stalks have been found to have elements of a CDS or dermoid cyst. We surgically treated a saccular lesion in the lumbosacral region of a 7-day-old male neonate. Although fetal magnetic resonance imaging (MRI) failed to reveal a stalk, postnatal MRI including three-dimensional heavily T2-weighted imaging demonstrated a stalk originating from the lumbar cord and extending caudally to enter the lumbosacral meningocele sac. During untethering surgery, we found that the stalk was slender, with a diameter of 0.7-0.8 mm, but otherwise appeared to be a typical LDM stalk. Histopathological examination revealed that the fibrocollagenous stalk contained glial fibrillary acidic protein-immunopositive neuroglial tissues and stratified squamous epithelium. The present report describes the first documented case of a stalk with combined features of saccular LDM and CDS in a neonate. Since cutaneous ectodermal tissue is likely to remain in the remnant stalk, this patient requires careful monitoring to detect the potential development of a dermoid cyst.