Diffuse Idiopathic Skeletal Hyperostosis in a Patient With Shoulder Pain.

A 74-year-old man was referred to physical therapy by his primary care physician for insidious onset of right shoulder pain. Following examination, spinal radiographs and the human leukocyte antigen (HLA-B27) test, which is used to identify common autoimmune disorders, were completed. The radiographs revealed multilevel changes consistent with diffuse idiopathic skeletal hyperostosis, and the HLA-B27 test was positive. J Orthop Sports Phys Ther 2020;50(4):215. doi:10.2519/jospt.2020.9243.

Pathogenesis of hyperostosis: a key role for mesenchymatous cells?

The similarities between diffuse idiopathic skeletal hyperostosis (DISH) and some forms of ankylosing spondylitis suggest shared pathogenic mechanisms. Entheseal ossification progresses at the same rate in the two conditions, and spondyloarthritis was the first diagnosis considered in several families with genetically determined early-onset DISH. However, DISH may be a heterogeneous condition, as the presence of peripheral calcifications in some families suggests pathogenic similarities with several animal models combining entheseal ossification and peripheral calcifications, as well as with X-linked familial hypophosphatemia and dentin-matrix-protein mutations. In the far more common presentation of hyperostosis without calcifications, entheseal ossification may be related to abnormal osteoblastic differentiation of mesenchymatous stem cells normally found around the intervertebral disks, in the vertebral periosteum, and in the anterior and posterior longitudinal ligaments. The many factors suspected of promoting this abnormal differentiation include bone morphogenetic proteins (BMPs), retinoids, and various hormonal factors; in addition, adipokines such as leptin are the focus of growing interest based on the well-documented association between DISH and obesity. Confirmation of the role for mesenchymatous cells in DISH should encourage investigations of mesenchymatous cells as possible pathogenic contributors to the entheseal abnormalities seen in spondyloarthritis. These cells normally exert immunosuppressive effects, which may be subverted in spondyloarthritis, notably by a T-cell population that homes specifically to the entheses.

New developments in our understanding of DISH (diffuse idiopathic skeletal hyperostosis).

PURPOSE OF REVIEW: Diffuse idiopathic skeletal hyperostosis (DISH) or Forestier's disease is a common disorder among older adults. The diagnosis is based solely on radiographic abnormalities defined using the Resnick criteria. DISH is characterized by ossification of the anterior longitudinal ligament of the spine and various extraspinal ligaments. DISH often coexists with OA, but patients affected by this disorder differ from patients with primary OA in several aspects: prevalence in the general population, gender distribution, anatomic site of primary involvement, magnitude and distribution in the spine and the peripheral joints. Purpose of this review is to summarize new clinical, pathogenetic and therapeutic insights of this disease. RECENT FINDINGS: Recent studies confirm that patients with DISH have a greater body mass index, higher serum uric acid levels and are more likely to have diabetes mellitus. In addition, DISH is most probably related to abnormal bone cell growth/activity reflecting the influence of metabolic factors that lead to new bone formation. Serum matrix Gla protein may be a marker of osteometabolic syndromes, such as DISH, that cause hyperostosis. SUMMARY: Many recent developments of DISH are described in this review. Possible pathogenetic mechanism driving bone deposition are discussed. DISH is still recognized radiographically; no specific drug has been yet identified.