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
Most common complication of mastectomy is: 
Select and explain. 
A. Seroma, B. Hemorrhage, C. Lympnedema, D. Infection
A: Seroma
Answer: A: Seroma 
Explanation: Seromas beneath the skin flaps or in the axilla represent the most frequent complication of mastectomy and axillary lymph node dissection, repoedly occurring in as many as 30% of cases. Ref: Schwaz's principle of surgery 9th edition, chapter 17.