Synovial Cysts Associated with Cauda Equina Syndrome in Two Dogs

Abstract

Synovial cysts should be considered in the differential diagnosis of dogs with cauda equina compression syndrome when lumbosacral degenerative joint disease is present.

Imaging Diagnosis—degenerative Intraspinal Cyst Associated With an Intervertebral Disc

“…5 In two dogs that developed cauda equina syndrome due to intraspinal synovial cysts it was speculated that the cysts were formed due to lumbar instability or abnormal biomechanics of the articular processes. 6 An intraspinal synovial cyst originating from the articular process at the level of T13-L1 has been reported in a Siberian husky cross. 7 In humans there are four theories about the pathogenesis of spinal synovial cyst formation.…”

“…As most spinal synovial cysts in dogs are associated with the true intervertebral joints, 5–7 the lesion in this dog had an atypical location for a typical synovial cyst. In contrast to a synovial cyst, a ganglion cyst has a connective tissue capsule without a synovial lining and does not communicate with the articular process joint.…”

“…In nine dogs with extradural synovial cysts originating from an articular process joint there was evidence of degeneration of the articular processes and adjacent intervertebral disc in all dogs 5 . In two dogs that developed cauda equina syndrome due to intraspinal synovial cysts it was speculated that the cysts were formed due to lumbar instability or abnormal biomechanics of the articular processes 6 . An intraspinal synovial cyst originating from the articular process at the level of T13–L1 has been reported in a Siberian husky cross 7 …”

“…The appearance of the lesion reported in our dog in MR images resembles the appearance of synovial cysts reported in humans 2,3,8,18,19 and dogs. 5,6 Synovial cysts usually have a signal intensity equal to or slightly greater than CSF in T1-and T2-weighted images; however, the signal intensity of the cyst is dependent on the composition of the fluid contained. Some cysts may show high signal in both T1-and T2weighted images due to proteinaceous fluid or paramagnetic blood breakdown products.…”

Lumbar Spinal ‘Juxtaarticular’ Cyst in a Gordon Setter

“…In dogs, spinal synovial cysts have been described in the cervical spine of large-breed dogs (Levitski et al, 1999;Dickinson et al, 2001;Lipsitz et al, 2001) at the thoracolumbar junction (Grevel and Cop, 1992 ;Levitski et al, 1999;Perez et al, 2000), in the caudal lumbar spine (Webb et al, 2001) and at the lumbosacral junction (Forterre et al, 2006). Dogs with extradural spinal synovial cysts have a history of chronic affection with slowly progressing symptoms over weeks or months (Levitski et al, 1999;Dickinson et al, 2001), although slight deficits can also acutely worsen (Perez et al, 2000).…”