A Rare and Underestimated, However, A Treatable Disease: Tarlov Cyst and Adhesive Arachnoiditis

Abstract

Tarlov cyst (TCs) is also called perineural cyst, which is a rare disease of the posterior nerve root prevalently localized in the lumbo-sacral region, however, it is also possible in every part of the spinal cord. These cysts represent a dilation of the nerve-root sheath that often communicate with subarachnoid space through a valve-like mechanism containing cerebrospinal fluid (CSF) and neural tissue. Tarlov cyst is often asymptomatic and discovered incidentally in the MRI, however, sometimes it can be symptomatic and is characterized by many symptoms, such as low back pain, sacral radiculopathy, sciatica, coccydynia or cauda equina syndrome, constipation, dyspareunia, urinary incontinence, and retention as well as blurry vision and headache. Moreover, these cysts can be a cause of CSF leak and therefore culprit of idiopathic intracranial hypotension. The etiopathogenesis is still unclear, but it is documented that a trauma, an old hemorrhage, and congenital and iatrogenic causes may be responsible for it. Association between the Tarlov cysts and the arachnoiditis have been studied in the last years. Tarlov cyst appears to be a consequence of the arachnoiditis. In general, there are four stages of arachnoiditis. In the last stage, it is possible that some patients cannot walk anymore becoming wheelchair bound. Moreover, arachnoiditis is often associated to type I ACM, syringomyelia and Ehlers-Danlos syndromes. Although Tarlov cyst has been known since 1938, the year in which Dr. Isador Max Tarlov described it first as an incidental finding in cadavers, nowadays many doctors do not really know this disease and underestimate it by thinking that it cannot be responsible for the above listed symptoms. The main aim of this work is to educate the medical community to consider Tarlov cyst in the differential diagnosis of back pain patients, and in other diseases. While the surgery represents the most effective therapy for such patients, a treatment of the arachnoiditis with the stem cells therapy should be also considered.