A classical expansive lytic lesion in the transverse process of a vertebra is seen in -
Both ABC and osteoblastoma can arise in the posterior elements of vertebrae (i.e. Pedicle, lamina, transverse process or spinous process).
ABC produces lytic (lucent) lesion, while osteoblastoma produces lytic lesion surrounded by a rim of sclerosis.
Osteosarcoma
Aneurysmal bone cyst
Osteoblastoma
Metastasis