Contrasting natural histories of thoracic spine pneumatocysts: resolutionversusrapid enlargement

Abstract

An intraosseous pneumatocyst is an unusual cause of gas in a vertebral body and is rarely reported in the thoracic spine. We report the evolution of thoracic spine pneumatocysts, one that enlarged rapidly with resorption of fluid and one that resolved. A 65-year-old female with lower back and left leg pain underwent MRI of the lumbar spine, which demonstrated a well-defined lesion in a T10 vertebral body of low-signal on T(1) and T(2) weighted imaging. CT confirmed this as a gas-containing cyst. Review of previous imaging showed that this lesion had initially contained fluid and had expanded rapidly over 14 months. It also showed smaller pneumatocysts, which had resolved. The variable natural history and imaging features of pneumatocysts make them an important differential diagnosis of an intravertebral lesion. Their aetiology is not known, but previous case reports suggest that they can occur spontaneously or in association with vacuum phenomenon in adjacent discs or facet joints. Previous reports have observed that they can fill with granulation tissue or fluid, and the case we report demonstrates that this fluid can be resorbed and that the pneumatocyst can undergo rapid enlargement. A pneumatocyst is a differential diagnosis for an expanding intravertebral lesion of indeterminate MRI characteristics. The diagnosis can be made with CT if the lesion is gas or gas and fluid filled.

İliak Kemiğin İntraosseöz Pnömokisti: BT Bulguları

“…İntraosseöz gaz birikimi, gaz oluşturan organizmalar nedeniyle gelişen osteomyelit neticesi de görülebilir. Pnömokist zamanla büyüyebilir ya da kaybolabilir (2). Kist içerisinde hava-sıvı seviyesi gelişebilir.…”

‘Abnormal’ cervical imaging?: Cervical pneumatocysts – A case report of a cervical spine pneumatocyst

“…These gas-filled cavities may also gradually 7 or rapidly enlarge. 12 Although there is certainly no indication for routine surgical management of pneumatocysts, enlarging cavities may need to be monitored if there is a risk of pathological fracture.…”

Intraosseous pneumatocyst of the cervical vertebra

“…7 Multiple vertebral pneumatocysts have also been reported. 8,9 They have been described with and without communication with the adjacent discs and joints and the spinal canal. 3,4,7 It has been proposed that intraosseous pneumatocysts either develop spontaneously or from vacuum degeneration of pre-existing intraosseous ganglia or synovial cysts.…”

“…While most pneumatocysts retain their size and appearance over years on imaging, gradual enlargement has also been reported. 8,9 Some have been reported to progress spontaneously to fluid-filled cysts and subsequent replacement by granulation tissue. 3 In others, the contents have progressed from fluid and gas to only gas.…”

“…3 In others, the contents have progressed from fluid and gas to only gas. 9 It has been speculated that gas and fluid accumulation occurs in the cyst due to a significant pressure gradient vis-à-vis the adjoining bone marrow. Kitagawa et al 8 proposed that pneumatocysts in younger patients are smaller and are likely to be spontaneous in origin, whereas in older patients they are larger and associated with degenerative disc disease.…”