This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Arterial Disorders, Subject name: Surgery
Eleven years after undergoing right modified radical mastectomy, a 61-year-old woman develops raised red and purple nodules over the right arm. What is the most likely diagnosis? 
Select and explain. 
A. Lymphangitis, B. Lymphedema, C. Lymphangiosarcoma, D. Hyperkeratosis
C: Lymphangiosarcoma
Answer: C: Lymphangiosarcoma 
Explanation: Lymphangiosarcoma is a rare complication of long-standing lymphedema, most frequently described in a patient who has previously undergone radical mastectomy (Stewart-Treves syndrome). It usually presents as blue, red, or purple nodules with satellite lesions. Early metastasis, mainly to the lung, may develop if it is not recognized early and widely excised. Lymphedema is a complication of radical mastectomy and presents as diffuse swelling and nonpitting edema of the limb. Lymphangitis and hyperkeratosis are complications of lymphedema.