Study design: A patient with sciatica resulting from a hemorrhagic cyst of the ligamentum flavum is reported. Surgical removal of the cyst relieved the patient of her sciatic symptoms.
Summary of background data: Cyst of ligamentum flavum is an uncommon cause of radiculopathy. There are 13 cases in the literature.
Conclusions: The differential diagnosis of benign interspinal extradural mass lesions includes spinal synovial cysts, ligamentum flavum cysts, perineural cysts, dermoid cysts, and parasitic cysts.