Review Question - QID 894

The clinical presentation and radiographic findings are consistent with diffuse idiopathic skeletal hyperostosis (DISH).

DISH is a common disorder of unknown etiology that is characterized by back pain and spinal stiffness. The condition is recognized radiographically by the presence of "flowing" ossification along the anterolateral margins of at least four contiguous vertebrae and the absence of changes of spondyloarthropathy or degenerative spondylosis. It is a challenge to differentiate between DISH and ankylosing spondylitis. In the cervical spine, anterior bone formation with preservation of disc space can help differentiate from AS (in AS bone formation is typically seen between vertebral bodies).

Resnick et al. investigated the radiographic and pathologic features of DISH. Pathologic features included diffuse calcification and ossification in the anterior longitudinal ligament, degeneration in the peripheral annulus fibrosis fibers, chronic inflammatory cellular infiltration, and periosteal new bone formation on the anterior surface of the vertebral bodies.

Belanger et al. reviewed the diagnosis and treatment of both spinal and extraspinal manifestations of DISH. They report in patients with DISH, even in patients who present with either lumbar or cervical symptoms, almost universally flowing osteophytes are seen on the right side of the thoracic spine. Thus, they emphasize that radiographic examination of this area is critical when attempting to establish a diagnosis of DISH.

Figure A shows typical cervical radiographs of DISH with anterior bone formation with preservation of disc space. Illustration A shows the typical lateral cervical radiographs seen with ankylosing spondylitis with bone formation within the intervertebral space. Illustration B shows a lateral in a patient with ossification of the posterior longitudinal ligament (OPLL). Notice the longitudinal "bar" posterior to the vertebral bodies. Illustration C shows basilar invagination which is one form of rheumatoid spondylitis. Illustration D shows the osteophytes consistent with osteoarthritis.

Incorrect Answers:
Answer 1: Ossification of the posterior longitudinal ligament is consistent with the radiographs in Illustration B.
Answer 2: Rheumatoid arthritis is consistent with the radiograph in Illustration C.
Answer 3: Ankylosing spondylitis is consistent with radiographs in Illustration A.
Answer 4: Osteoarthritis is consistent with the radiographs in Illustration D.