A 4-year-old child with decreased leg reflexes and a dimple above the gluteal cleft; which diagnosis may be considered?

• A. Spina bifida cystica
• B. Arnold-Chiari malformation
• C. Tethered cord
• D. Reye syndrome

Answer: (C)

A cutaneous marker in the lumbosacral region with leg neuro signs points to occult spinal dysraphism causing tethered cord. A dimple above the gluteal cleft is a classic sign that the spinal cord may be abnormally tethered by a midline tract or lipoma. As a child grows, the cord becomes stretched and traction is transmitted to the neural elements, leading to lower-limb symptoms such as decreased leg reflexes, weakness, and gait changes. This pattern fits tethered cord because it links a simple skin finding with progressive spinal cord dysfunction.

Spina bifida cystica would usually present with an obvious open spinal defect or mass at birth, not just a small dimple. Arnold-Chiari malformation involves downward displacement of brain structures and presents with brainstem/cerebellar symptoms rather than isolated leg reflex changes tied to a gluteal dimple. Reye syndrome is a systemic encephalopathy with hepatic involvement after viral illness and has no relation to spinal dysraphism or cutaneous lumbosacral markers.