Discal cyst

Discal cysts (also known as a disk cyst or disc cyst) are uncommon lesions of the spine, representing an extrathecal cyst which communicates with the adjacent intervertebral disc through an annular fissure. 

The vast majority of discal cysts, as rare as they are, have been reported in males (M:F 9:1), typically of Asian ethnicity 1,2. They are usually found in young adults 1,2

Clinical presentation is indistinguishable from disc herniation with sciatica and back pain the most common presenting symptoms 2

The aetiology of these discal cysts remains uncertain, but they are believed to occur due to traumatic disruption of the annulus with subsequent accumulation of fluid, which forms a surrounding pseudocapsule 1,2. In support of this theory is the fact that they are primarily encountered in young men, and are often haemorrhagic at surgery 1

Disc cysts have been most commonly reported at the L4/5 level 1. MRI is required for assessment of these lesions. 

MRI

Disc cysts appear as sharply circumscribed lobulated cystic lesions in the anterior epidural space communicating with the disc space via a stalk through an annular fissure.  

Typical signal intensity is as follows 1:

  • T1
    • variable signal intensity
    • usually hypointense
  • T2
    • usually hyperintense
    • low signal rim
    • occasionally a fluid/fluid or blood/fluid level is seen
  • T1 C+
    • peripheral enhancement
Discography

If performed, contrast injected into the disc space passes into the cyst 1,2

Treatment is not always required and discal cysts have been reported to spontaneously regress 1. Epidural steroid / local anaesthetic may be useful temporising measures. 

CT guided aspiration has been reported 1. Microsurgical resection is the more common alternative if symptomatically required 1,2

Imaging differential considerations include 1


Spine
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Article Information

rID: 45139
Tags: refs, cases
Synonyms or Alternate Spellings:
  • Disk cyst
  • Disc cyst
  • Discal cyst

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