DISH (Diffuse Idiopathic Skeletal Hyperostosis, Forestier disease) is a non-inflammatory condition characterized by flowing ossification along the anterior longitudinal ligament (ALL). According to Resnick criteria, anterior ossification across 4 or more contiguous vertebrae, preserved disc spaces, and absence of sacroiliac/facet joint involvement form the diagnostic triad. The thoracic region is most commonly affected (70%) and right-sided dominant ossification is typical — the pulsatile pressure of the thoracic aorta mechanically inhibits ossification on the left side. Prevalence in the >50 age population is 12-22%, with a 2:1 male predominance. It has a strong association with diabetes mellitus, obesity, and metabolic syndrome. Generally asymptomatic and detected incidentally, but cervical DISH can cause dysphagia with large anterior osteophytes.
Age Range
50-85
Peak Age
65
Gender
Male predominant
Prevalence
Common
The pathogenesis of DISH is not fully understood, but metabolic factors (insulin-like growth factor-1, vitamin A derivatives) and mechanical stress are strongly implicated. In the disease, heterotopic bone formation occurs along Sharpey fibers within the anterior longitudinal ligament — this process is membranous ossification, not endochondral ossification. Insulin and IGF-1 stimulation of osteoblast proliferation explains DISH's association with diabetes and metabolic syndrome. Right-sided dominance in the thoracic region is explained by mechanical inhibition: the thoracic aorta runs close to the vertebral body on the left side, generating pulsatile pressure with each heartbeat — this pressure mechanically prevents ALL ossification on the left. On CT, the ossified ALL appears as a flowing high-density bony structure on the anterior vertebral surface because newly formed bone images at cortical density (~500-1000 HU). Disc spaces are preserved because the pathological process affects the ligament, not the disc material — this is the fundamental difference from AS annulus fibrosus involvement. On MRI, the ossified ligament is hypointense on T1 and T2 because cortical bone has very low proton density and generates no signal.
The signature finding of DISH is flowing coarse ossification along the anterior longitudinal ligament across 4+ consecutive levels in the thoracic spine with prominent right-sided lateralization. This combination, together with preserved disc spaces and normal facet joints, confirms the DISH diagnosis. Right-sided dominance reflects the mechanical inhibition effect of the thoracic aorta on the left and is nearly pathognomonic for DISH.
Flowing, coarse ossification along the anterior longitudinal ligament. High-density bony structure showing continuity across 4+ consecutive levels on the anterior vertebral surface. Ossification thickness can range from 3 mm to >10 mm. Ossification may form a bridge at disc level or show a short interruption, but disc space is preserved.
Report Sentence
Flowing ossification along the anterior longitudinal ligament between T___-T___ levels in the thoracic spine is identified, consistent with DISH (Forestier disease); disc spaces and facet joints are preserved.
Ossification prominent on the right side and diminished or absent on the left in the thoracic region. Best evaluated on coronal (frontal) CT reformat. The pulsatile pressure of the thoracic aorta on the left mechanically inhibits ossification. This asymmetric pattern is nearly pathognomonic for DISH.
Report Sentence
Anterior ossification in the thoracic spine is right-sided dominant with diminished ossification on the left adjacent to the thoracic aorta; this asymmetric pattern is consistent with DISH.
Critical component of DISH diagnostic triad: disc spaces and facet joints appear normal. Disc height is preserved, no vacuum phenomenon or advanced degeneration findings. No erosion, sclerosis, or ankylosis in facet joints. This finding is critical for distinguishing from AS (facet ankylosis, disc degeneration) and degenerative spondylosis (disc narrowing, osteophytes).
Report Sentence
Despite anterior ossification, disc spaces and facet joints are preserved, supporting the diagnosis of DISH and excluding ankylosing spondylitis.
Large anterior osteophytes in the cervical region. Can cause dysphagia, dysphonia, and even airway obstruction by compressing the esophagus and laryngeal structures. C3-C6 are most commonly affected levels. CT sagittal reformat evaluates the size of anterior osteophytes and proximity to the airway.
Report Sentence
Large anterior osteophytes at C___-C___ levels in the cervical spine are identified, consistent with cervical DISH; clinical correlation for esophageal and airway compression is recommended.
Extraspinal enthesophytes: iliac crest, calcaneus, olecranon, patella, greater trochanter, ischial tuberosity enthesophytes. Supports DISH being a systemic ossification disorder. May be incidentally detected on pelvic or extremity CT.
Report Sentence
In addition to spinal ossification, extraspinal enthesophytes (iliac crest/calcaneus/olecranon) are identified, supporting the systemic nature of DISH.
Criteria
Anterior ossification across 4+ consecutive levels in thoracic region. Most common DISH form (70%).
Distinct Features
Right-sided dominant ossification. Usually asymptomatic. Minimal movement restriction.
Criteria
Anterior ossification in cervical region. Bilateral symmetric (no aorta). C3-C6 most common.
Distinct Features
Dysphagia is most important symptom (large anterior osteophytes compress esophagus). Rarely airway obstruction. Surgical osteophyte excision may be needed. Risk of difficult intubation.
Criteria
Combined thoracic + lumbar + cervical involvement. Widespread extraspinal enthesophytes.
Distinct Features
Advanced metabolic syndrome association. Multilevel movement restriction. Increased fracture risk (rigid spine).
Distinguishing Feature
AS has thin symmetric syndesmophytes + facet joint ankylosis + bilateral sacroiliitis; DISH has coarse anterior ossification + preserved facet joints + no sacroiliitis
Distinguishing Feature
OPLL has posterior ligament ossification (PLL), cervical predilection, spinal canal narrowing; DISH has anterior ligament ossification (ALL), thoracic predilection, canal narrowing rare
Distinguishing Feature
Spondylolysis has isolated pars defect, young age; DISH has diffuse anterior ossification, >50 years, no pars defect
Urgency
routineManagement
conservativeBiopsy
Not NeededFollow-up
no-follow-upDISH is generally an asymptomatic and benign condition requiring no treatment. Anterior osteophyte excision can be performed when cervical DISH causes dysphagia. Screening for diabetes and metabolic syndrome is recommended. Risk of difficult intubation should be kept in mind for anesthesia. DISH and AS can coexist — separate evaluation of criteria for both diagnoses is important.
DISH is generally asymptomatic and detected incidentally. Cervical DISH can cause dysphagia and may require surgical intervention. Thoracic DISH may present with restricted mobility and rarely spinal stenosis. It is associated with diabetes and metabolic syndrome. Treatment is symptomatic.