Massive cystic dilatation within a tethered filum terminale causing cauda equina compression and mimicking syringomyelia in a young adult patient

Background: The ventriculus terminalis (VT) is formed during early embryonic development of the spinal cord and can only be identified histologically in both children and adults. Cystic dilatation of the VT can be seen in young children, but it rarely persists through adulthood. Clinical case: We describe a 27-year-old female with paraparesis secondary to a massive and tethered cystic dilatation of the VT mimicking syringomyelia. Symptoms appearing in early childhood were ignored, probably leading to the much prominent presentation in early adulthood. The preoperative presentation and surgical treatment are discussed in relation to childhood history. Conclusions: Although extremely rare, symptomatic dilatation of the VT can be seen in young adults, usually with previous manifestations in early childhood. This entity should be considered while treating tethered cord spectrum.