Final answer:
The correct code for a patient with malignant melanoma of the skin of the back, nose, and scalp who will undergo a radical excision of the melanoma is C43.22.
Step-by-step explanation:
The correct code for a patient with malignant melanoma of the skin of the back, nose, and scalp who will undergo a radical excision of the melanoma would be C43.22. The code C43 is used for melanoma of the skin, and the additional digit 2 after the decimal point specifies that the melanoma is located on multiple sites (the back, nose, and scalp).