Co-existing limited dorsal myeloschisis, spinal dermal sinus tract, and dermoid cyst in a 3-month-old female infant: Illustrative case.

Limited dorsal myeloschisis (LDM) and spinal dermal sinus tracts (DST) are rare forms of closed spinal dysraphism that are usually considered distinct entities, and their coexistence with a dermoid cyst is exceptionally uncommon. We describe a 3-month-old female infant with a congenital lumbosacral swelling; MRI revealed a subcutaneous cyst with imaging features suggestive of an epidermoid-type lesion, a fibro-neural stalk, and associated tethered cord, syrinx, and dorsal tenting. The patient underwent complete excision of the cyst and removal of the fibro-neural stalk along with its dural attachment site, followed by untethering; histopathology confirmed coexisting LDM and DST with a dermoid cyst. This case highlights that although LDM and DST have distinguishable features, they may rarely coexist, and complete resection of the stalk, including its dural insertion, is essential to prevent infection and ensure that an associated DST is not missed.