Dense bone around the sacroiliac joint: a radiological review of the differential diagnosis.

Solitary osteosclerotic bone lesions around the sacroiliac (SI) joints are described as seen on plain radiographs or conventional tomography, with the descriptive attributes ranging from round to ovoid over square and triangular to multiform. The etiology of the solitary osteosclerotic lesions around the SI joint can often be concluded from the radiographic appearance, sometimes complemented by the presentation on CT and/or scintigraphy.