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: Surgery
Abbe-Estlander flap is used in repair of: 
Select and explain. 
A. Breast, B. Lip, C. Esophagus, D. None of the above
B: Lip
Answer: B: Lip 
Explanation: The lip-switch (Abbe-Estlander) flap or a stair-step advancement technique can be used to repair defects of either the upper or lower lip. Microstomia is a potential complication with these types of lip reconstruction. Ref: Schwaz's principle of surgery 9th edition, chapter 18