Sacral Tarlov Cyst as a Rare Cause of Lower Limb Radiculopathy in a Child.

Tarlov cysts (TC) are uncommon perineural cysts that may arise anywhere along the spine, especially in the sacral region. To date, symptomatic TCs in children are very rare. Most of these benign lesions tend to be incidental discoveries during neuroimaging for other reasons. Nonetheless, they have been occasionally reported to cause sensorimotor-related neuropathy in the lower back, pelvis, legs, and urogenital system due to direct compression of the adjacent nerve roots. Management of adult TCs is well-described. In contrast, there is a paucity of contemporary literature on symptomatic TCs that are surgically treated in children. We report an unusual case of a paediatric patient who presents with lower limb radiculopathy secondary to large sacral TCs and discuss the management. A previously well 9-year-old female was referred for persistent lower back pain and left leg pain over a period of 2 months. There were no associated bladder or bowel symptoms. Clinical examination demonstrated a positive straight leg raise on the left and reduced sensation along the posterior left thigh, calf, foot dorsum, and toes. Magnetic resonance imaging (MRI) of her spine showed prominent, large perineural cysts surrounding bilateral S1 and the right S2 cauda equina nerve roots. Of note, there was associated bony expansion and scalloping of the sacral canal and corresponding sacral foramina. After a failed trial of conservative treatment, she underwent a laminotomy, wide fenestration, and excision of TCs. Postoperatively, her symptoms improved significantly. At 12 months' follow-up, there was no recurrence of the patient's lower back and leg symptoms. We describe an unusual case of symptomatic sacral TC in a child, whereby surgical treatment is a feasible treatment option in this age group.