Diffuse idiopathic skeletal hyperostosis (DISH) or Forestier disease
It is bulky flowing ossification of anterior longitudinal ligament (ALL)
The etiology of DISH is uncertain. Glucose metabolism imbalance (diabetes), dyslipidemia, and hyperuricemia have been implicated.
DISH diagnostic criteria include the following
- Flowing calcifications and ossifications along the anterolateral aspect of at least 4 contiguous vertebral bodies, with or without osteophytes
- Preservation of disk height in the involved areas and an absence of excessive disk disease
- Absence of bony ankylosis of facet joints and absence of sacroiliac erosion, sclerosis, or bony fusion
Unlike ankylosing spondylitis, DISH does not involve the sacroiliac joint. Patients with DISH infrequently demonstrate disk height reduction or vacuum changes.
Location
Lower thoracic spine involvement is typical of DISH, but the lumbar and cervical spine also can be affected. The left side of the spine typically is spared or less involved, which probably is attributable to the pulsating aorta.
Imaging findings
Radiography
- Flowing anterior vertebral ossification, variably distinguishable from anterior vertebral body cortex
- Earliest sign = new bone formation adjacent to mid-vertebral body
- Relative preservation of disc spaces, facets
CT Findings
- Thick ALL ossification, R > L
- Relatively minimal degenerative disc, facet disease
- Absent facet, sacroiliac joint erosion or ankylosis
- DISH changes detectable in-between disc levels
- Spondylosis centered at disc level
Associated abnormalities
- Ossification of posterior longitudinal ligament (OPLL).
- Exuberant enthesial reaction at tendon, ligament, and joint capsule insertions.