Ring sign: an imaging sign for osteochondromyxoma in Carney complex.

Background: To introduce the concept of "ring sign" and to evaluate its role in the diagnostic imaging of osteochondromyxoma in patients with Carney complex (CNC).

Methods: Three patients presenting osteochondromyxoma with CNC were included for evaluation of the ring sign on different imaging modalities, including radiographs, computed tomography, and magnetic resonance imaging. The literature was reviewed for further discussion.

Results: The ring sign in osteochondromyxoma could be seen on radiographs, computed tomography, and magnetic resonance images in all three patients at each of the involved sites. The morphological patterns and the number of ring signs varied by case, site, and imaging method. Some previous reports have shown images that contain ring signs, but do not identify them as such.

Conclusions: Ring sign can be considered as a relatively specific sign, helpful for the imaging diagnosis of osteochondromyxoma in the CNC.