Bone tumours of Ribs

Regarding the benign bone tumours of the ribs,

1. Enchondroma (EC) are the most common benging tumours of the ribs.
2. Fibdrous dysplasias (FD) are usually seen in the posterior or lateral aspects of the ribs.
3. MRI is very sensitive in diagnosing the non-calcified cartilage of enchondroma.
4. In osteochondromas (OC), cartilage cap of less than 10mm is highly suspicious for malignant transformation.
5. Aneurysmal bone cysts (ABC) are commonly seen in the anterior aspect of the ribs.

Answers: F, T, T, F, F
Notes: Fibrous dysplasia is the most common benign rib tumour, followed by enchondroma and osteochondroma. FD usually occurs in the posterior or lateral ribs, where as EC and OC occur anteriorly at the costochondral junctions. Hyaline cartilage is not calcified and is best seen on T2WI as a bright signal. Cartilage cap of more than 2 cm in adult and 3 cm in children is highly suspicious for malignant transformation in OC. ABCs are usually seen in the posterolateral aspect of the ribs.
Reference:

1. Hughes et al. Benign primary tumours of the ribs. Clin rad (2006): 61:314-322