Usually, the Tarlov's cysts appear with a variety of neurologic symptoms. These strange perineurial cysts are too soft to destruct bone structures even when get enlarged. If fracture occurs, one should consider another pathology,

Dear Sujal

Tarlov cysts most often are found in the sacral spinal canal, where they can produce bone erosion and compression of adjacent spinal nerve roots, resulting in a debilitating sacral radiculopathy syndrome. Tarlov cysts can be single or multiple, and can develop anywhere along the spine where nerve roots are present. Progressive cyst enlargement can cause significant bony erosion and impingement of adjacent spinal nerve roots, producing corresponding radiculopathies. The pathogenesis of Tarlov cysts remains unclear. Tarlov proposed that cyst formation could be the result of trauma, ischemic degeneration, inflammation, or hemorrhagic infiltration from the subarachnoid space

This article may be useful for you

Voyadzis J.M., Bhargava P., Henderson F.: Tarlov cysts: a study of 10 cases with review of the literature. J Neurosurg Spine 2001; 95:25-32.

In spite of the "bone erosion" in case of a Tarlov cyst enlargement, pathological fractures of the sacrum are very rare, if ever.