system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
A classical expansive lytic lesion in the transverse process of a vertebra is seen in -
assistant
The correct answer is  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.