[Thoracic hyperostoses. Description, nosology, etiology]

Thoracic hyperostosis is a bone disease with an inflammatory appearance which results in hypertrophy and condensation of the bony elements of the anterior thorax, the sternum, the clavicle and the ribs. 14 cases of the primary form of this disease, Köhler's primary sterno-costo-clavicular hyperostosis, have been reported in the literature. This benign disease is associated with only one complication: subclavian vein thrombosis. The secondary forms of thoracic hyperostosis are associated with extrathoracic signs and occur in a context suggestive of spondyloarthropathy. A sub-group is distinguished on the basis of the presence of cutaneous signs: hyperostosis associated with osteoarthritis in the context of palmo-plantar pustulosis (Sonozaki's disease) or severe forms of acne. In the absence of cutaneous signs, thoracic hyperostosis has been exceptionally described in cases of ankylosing spondylitis. It can also be integrated into a more autonomous context, associated with unilateral sacro-iliitis or with vertebral and peripheral osseous condensations. The pathophysiology of thoracic hyperostosis is unknown, but the HLA B27 phenotype does not appear to be involved.