Sacral perineurial (Tarlov) cysts are rare lesions. Over a seven year period 
4000 patients underwent surgery for lumbar disk herniation. In three patients 
neurological symptoms were caused by large sacral perineurial cysts. Methods of 
choice for diagnosis of Tarlov cysts are lumbosacral magnetic resonance imaging 
and computerized tomography myelography. The majority of Tarlov cysts are 
asymptomatic. In case of large (> or = 1.5 cm) and symptomatic perineurial cyst, 
as in three patients reported in this article, microsurgical treatment was 
successful. Although rare, perineurial (Tarlov) cysts must be taken into 
consideration when approaching to patient with low back and radicular pain. 
Authors review the medical literature, pathological and pathophysiological 
features and treatment options of sacral perineurial cysts.