rings and arcs calcification
Rings and arcs calcification is characteristic of chondroid lesions, such as enchondromas and chondrosarcomas. It is due to endochondral mineralization of multiple hyaline cartilage nodules and is similar to popcorn calcification, which has rings and arcs on the background of more amorphous calcification.
In general well-formed rings and arcs are seen in lower grade tumors (see chondrosarcoma grading).
Although considered so by some, the appearance is not pathognomonic for chondral calcification. Rarely, rings and arcs calcification have also been seen with osteoblastomas, as well as CPPD. Nevertheless, the presence of rings, arcs and/or popcorn calcification is highly specific for a chondroid lesion.