Tarlov cysts: an unusual case of perianal pain

Abstract

A 74-year-old man with no relevant personal history, presented to our outpatient gastroenterology practice with complaints of perianal pain for 2 months. The pain was dull and was intensified by movement and local pressure. No relieving factors or association with other symptoms were identified. According to the patient related, the onset of symptoms was associated with a transrectal ultrasoundguided prostate biopsy that he had previously undergone. There were no abnormal findings on physical examination or on colonoscopy. Magnetic resonance imaging of the lumbosacral spine identified two cystic formations, 5 and 12 mm in diameter in the sacral region of the spinal canal (Fig. 1), which were classified as Tarlov cysts. The patient was treated symptomatically for his lumbar pain with nonsteroidal anti-inflammatory drugs and analgesics and was later referred for a neurosurgery consultation for further evaluation and treatment. Tarlov or perineural cysts are extradural meningeal dilations arising from the posterior spinal nerve near the dorsal root ganglion. The cysts are usually asymptomatic and in most cases are diagnosed as an incidental finding [1]. The real prevalence of these structures in the adult population is estimated to be between 4.6 and 9 % [2]. These structures that have been found at all levels of the spinal medulla are most common in the sacral region, especially at the S2/S3 level. Usually, they are multiple and bilateral. Tarlov cysts are usually clinically insignificant. Nevertheless, due to pressure exerted on nerve tissue and bone, they can become symptomatic. Symptoms like lumbar pain, sciatic nerve pain, neurogenic claudication, paraesthesia of the lower extremities, muscular weakness, genitourinary changes (e.g. functional impotence and urinary incontinence) or gastrointestinal symptoms (e.g. perianal pain and changes in bowel habits) have been reported. The growing use of radiological imaging has made possible a more frequent identification of these structures. Magnetic resonance imaging is the gold-standard for diagnosing Tarlov cysts. Fig. 1 T1 weighted magnetic resonance image showing a 12-mm Tarlov cyst