Congenital dermal sinus.

congenital dermal sinus tract is an uncommon type of spinal dysraphism that results when a focal area of the ectoderm fails to separate from the underlying neuroectoderm, a process termed nondysjunction. Nondysjunction prevents the insertion and subsequent development of mesodermal tissue, which normally separates the spinal cord from the skin. Congenital dermal sinus tracts occur rarely and are usually located in the lumbar or lumbosacral regions. Skin findings include abnormal pigmentation, subcutaneous lipomas, skin tags, hypertrichosis, angiomas, infection, and sinus ostia with a cephalically oriented tract, which may prompt further investigation and subsequent diagnosis. Congenital dermal sinus tracts may also be seen with other pathologic inclusion tumors such as dermoids, epidermoids, and teratomas. Treatment is surgical excision, with successful results in more than 90% of patients.1 To our knowledge, neither antenatal diagnoses nor cutaneous cystic findings have been reported for congenital dermal sinus tracts to date. We report a case of a dermal sinus incorrectly identified prenatally and postnatally as myelomeningocele.