This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Abdomen & Pelvis, Subject name: Anatomy
Radiographic studies of a 42-year-old woman reveal that she has a vulvar malignancy involving the clitoris. Removal of all affected lymph nodes would be indicated to avoid spread of this cancer. Which are the first lymph nodes to filter the lymphatic drainage of the involved area? 
Select and explain. 
A. Superficial and deep inguinal lymph nodes, B. Internal iliac nodes, C. Paraaortic lymph nodes, D. Presacral lymph nodes
A: Superficial and deep inguinal lymph nodes
Answer: A: Superficial and deep inguinal lymph nodes 
Explanation: The deep inguinal lymph nodes drain the glans clitoris and receive lymph also from superficial nodes. The internal iliac nodes drain the inferior pelvic structures, deep perineal structures, and sacral nodes. The paraaortic lymph nodes, or lumbar nodes, receive lymph from the common iliac nodes. The drainage of presacral lymph nodes can pass to the common or internal iliac nodes. Axillary nodes drain body wall structures above the T10 dermatome (or the umbilicus).