Rib hyperostosis: a benign entity with suspicious imaging features.

Rib hyperostosis has previously been described in conjunction with disorders causing excessive vertebral ossification due to osseous bridging across the costovertebral joint, such as in diffuse idiopathic skeletal hyperostosis. Hyperostosis is believed to be a reactive process due to altered forces across the affected rib as bridging osteophytes decrease mobility at the respective costovertebral joint. The imaging characteristics of rib hyperostosis can be highly suspicious for malignancy.