This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Orthopaedics
According to the Enneking system, not true regarding an active benign tumour is - 
Select and explain. 
A. Intracapsular, B. Margin of reactive bone, C. Thick rim of reactive bone, D. Extended curettage is treatment
C: Thick rim of reactive bone
Answer: C: Thick rim of reactive bone 
Explanation: Enneking active stage of benign tumors is stage 2 in which tumor is actively growing and can cause symptoms of pathological fracture.
Radiograph shows well defined margins with a thin rim of reactive bone. Tumor may expand and thin the cortex.
Treatment usually consists of extended curettage, e.g. in ABC.