This case demonstrates an L3-4 disc protrusion and associated discal cyst compressing the left L4 nerve root in the subarticular recess. There is also L5-S1 disc protrusion with early discal cyst formation.
Discal cysts occur when there is a communication between an intervertebral disc and an extradural cyst, thought to be due to a traumatic injury to the annulus fibrosis. It is a rare diagnosis with relatively few cases described in the literature, but appears to be most common in young males (90% male, average age 33.5 years) 1. Discal cysts may regress spontaneously or can be resected surgically 1.