Diffuse Idiopathic Skeletal Hyperostosis and Ankylosing Spondylitis: A Challenging Case and Review of the Literature

Abstract

Background: Diffuse idiopathic skeletal hyperostosis and spondyloarthritis share similarities in clinical and radiological findings. In this article, we report a case of overlapping of these two hyperostotic diseases followed by an extensive narrative review of the literature focusing on the gray areas in the diagnosis of diffuse idiopathic skeletal hyperostosis.

Case description: We report the case of simultaneous diffuse idiopathic skeletal hyperostosis and ankylosing spondylitis in a 57-year-old man. The diagnosis was made after many collegial meetings based on solid radiological arguments.

Conclusion: Review of the literature reveals many uncertainties in the diagnosis of diffuse idiopathic skeletal hyperostosis, especially in the radiological evaluation of sacroiliac joints. Diffuse idiopathic skeletal hyperostosis and ankylosing spondylitis frequently overlap in important radiological features leading to diagnostic ambiguity and they can also co-exist in the same patient.

Keywords: Diffuse idiopathic skeletal hyperostosis; ankylosing spondylitis; co-existence; co-occurrence; spondyloarthritis.

Figure 1. 57-year-old male patient diagnosed with both Diffuse Idiopathic Skeletal Hyperostosis and Spondyloarthritis

Technique: Lateral and Antero-Posterior X-rays of the cervical Spine Findings: Multilevel degenerative changes, partial ankylosis of facet joints at C2–C3 (Arrow). Exuberant and prodigious osteophytes involving the bodies of C3-C4-C5-C6. Elongated ossification of the frontal planes of the vertebral bodies especially at the level of C4 responsible of a marked displacement the hypopharynx anteriorly (Asterisk).

Figure 2. 57-year-old male patient diagnosed with both Diffuse Idiopathic Skeletal Hyperostosis and Spondyloarthritis

Technique: Axial contrast enhanced CT scan of the neck (300 mA, 120 kV, 2 mm slice thickness, 100 ml of Xenetix 350, biphasic injection technique) Findings: Confirmation of the radiographic findings on cervical films. Anterior ossified cervical mass responsible for a mechanical obstruction and compression of the esophagus (narrow arrow) and an anterior displacement of the larynx (bold arrow).

Figure 3. 57-year-old male patient diagnosed with both Diffuse Idiopathic Skeletal Hyperostosis and Spondyloarthritis

Technique: Lateral and Antero-Posterior (AP) X-rays of the thoracic Spine Findings: Flowing ossifications involving the anterior longitudinal ligament along multiple contiguous thoracic levels with preservation of the intervertebral disc height at the involved vertebral segments on the lateral film as well as calcifications of the annulus fibrosus

Figure 4. 57-year-old male patient diagnosed with both Diffuse Idiopathic Skeletal Hyperostosis and Spondyloarthritis

Technique: Lateral and Antero-Posterior X-rays of the lumbar Spine Findings: Flowing ossifications along the anterolateral aspects of the lumbar spine. Exuberant beak-like bridging osteophytes. Apophyseal joint osteoarthritis.

Figure 5. 57-year-old male patient diagnosed with both Diffuse Idiopathic Skeletal Hyperostosis and Spondyloarthritis. (Magnification is seen below)

Technique: Antero-Posterior X-ray of the pelvis Findings: Left sacroiliac joint fusion. Sclerosis of the joint margins. Irregularities of the subchondral bone cortices are visible despite the projection of the gas within the overlying bowel making the interpretation of erosion and variation in joint width more difficult. Hip joint changes: joint space narrowing with subchondral cysts and overgrown osteophytes of the acetabuli.

Figure 6. 57-year-old male patient diagnosed with both Diffuse Idiopathic Skeletal Hyperostosis and Spondyloarthritis

Technique: Axial view of the contrast enhanced CT scan of the chest CT scan of the neck (300 mA, 120 kV, 2 mm slice thickness, 100 ml of Xenetix 350, biphasic injection technique) Findings: Narrow arrow points at a complete ankylosis of the costovertebral joint with a complete obliteration of the articular surface. Wide arrow points at a complete ankylosis of the costotransverse joint with a complete obliteration of the articular surface

Figure 7. 57-year-old male patient diagnosed with both Diffuse Idiopathic Skeletal Hyperostosis and Spondyloarthritis

Technique: MRI 3 tesla, Sagittal view, T2 weighted fat suppression sequence showing the lower spine. Findings: Paravertebral soft tissue inflammation surrounding the intervertebral ossifications at the level of L3–L4.

Figure 8. 57-year-old male patient diagnosed with both Diffuse Idiopathic Skeletal Hyperostosis and Spondyloarthritis

Technique: MRI 3 tesla of the sacroiliac joints, coronal view. a. T2 weighted sequence with fat suppression on the left. b. T1 weighted sequence of the right. Findings: Bilateral chronic sacroiliitis is present. Bone marrow edema is present on both sacral and iliac sides of the right sacroiliac joint. Irregular margins of the right SI joint. On the left, the articular surface is less visible confirming the aspect of partial ankylosis on conventional radiographs. Bilateral fat metaplasia predominant on the sacral subchondral bone bilaterally.

Figure 9. 57-year-old male patient diagnosed with both Diffuse Idiopathic Skeletal Hyperostosis and Spondyloarthritis

Technique: CT scan of the pelvis (275 mA, 120 kV, 3 mm slice thickness) a. Axial view of the sacroiliac joint b. Axial view of the sacroiliac joint c. Coronal view of the sacroiliac joint d. Axial view of the sacroiliac joint Findings: In addition to changes found in DISH such as para-articular bridging (asterisk in images a,b,d) and ankylosis of the entheseal part of the SIJ (as shown in image b), there is partial ankylosis of the synovial part of the left SIJ (best shown in image c) as well as subchondral sclerosis, erosions, ankylosis and joint irregularities of the synovial part of the right sacroiliac joint (best shown in images a and d).

Figure 10. 57-year-old male patient diagnosed with both Diffuse Idiopathic Skeletal Hyperostosis and Spondyloarthritis

Technique: Anteroposterior views of the shoulders Findings: Bilateral degenerative changes of the glenohumeral joints more prominent on the left. Loose osteocartilaginous bodies in the left glenohumeral joint.

Figure 11. 57-year-old male patient diagnosed with both Diffuse Idiopathic Skeletal Hyperostosis and Spondyloarthritis

Technique: Anteroposterior views of the hands Findings: Degenerative changes of the interphalangeal joints bilaterally.

Figure 12. 57-year-old male patient diagnosed with both Diffuse Idiopathic Skeletal Hyperostosis and Spondyloarthritis

Technique: Lateral views of the knees Findings: Bilateral ossified patellar enthesopathies (circles).

Figure 13. 57-year-old male patient diagnosed with both Diffuse Idiopathic Skeletal Hyperostosis and Spondyloarthritis

Technique: Post-operative lateral film of the cervical spine Findings: Operative resection of the cervical ossified mass followed by a one level instrumented cervical fusion of C4–C5

Figure 14. 57-year-old male patient diagnosed with both Diffuse Idiopathic Skeletal Hyperostosis and Spondyloarthritis

Technique: MRI 1.5 T of the sacroiliac joints after treatment, coronal view. a. T2 weighted sequence with fat suppression on the left b. T1 weighted sequence of the right Findings: Notice the decrease in bone marrow edema of the right sacroiliac joint before and after treatment

Figure 15. 57-year-old male patient diagnosed with both Diffuse Idiopathic Skeletal Hyperostosis and Spondyloarthritis

Technique: Comparison of T2 weighted sequence, coronal view, MRI of the sacroiliac joints (1.5 Tesla) a. Before treatment on the left b. 11 months after Secukinumab on the right Findings: Notice the decrease in bone marrow edema of the right sacroiliac joint before and after treatment.

Figure 16. 57-year-old male patient diagnosed with both Diffuse Idiopathic Skeletal Hyperostosis and Spondyloarthritis

Technique: MRI of the lumbar spine, sagittal view (1.5 Tesla) a. T1 weighted sequence of the left b. T2 weighted sequence with fat suppression on the right Findings: In addition to the anterior ossifications of the lumbar spine, we can see degenerative changes especially at the level of L3–L4