Tumor & tumour like: Osteochondroma (OC)

Hamartomous cartilage capped bony growth
Nearly 50% of benign bone tumours

OC of rib:
8% of benign rib tumours
Typically occur at costochondral junction
Pedunculated or sessile
Cartilage cap may show punctate calcification, ring or arc shaped ossification
Cartilage cap > 2cm in adult and 3 cm in children should raise a suspicion of malignant transformation
Differentiation from overlying bursa can be achieved by Gd-enhancement, where a bursa may demonstrate rim enhancement
Mineralised cartilage is low on all sequences, non-mineralised is low-to-int on T1 and high signal on T2

OC spine:
Most common in C spine - common in atlanto axial region
Most commmon in spinous ot transverse process
1. Hughes et al. Benign primary tumours of the ribs. Clin rad (2006): 61:314-322
2. Rodallec MH et al. Diagnostic Imaging of Solitary Tumors of the Spine: What to Do and Say. RadioGraphics 2008;28:1019-1041