CPT® code 15786 is used for abrasion treatment of a single lesion (e.g., for keratosis) through techniques like dermabrasion (lightly sanding the skin's surface). When treating multiple lesions in this manner, each lesion treated should be coded individually.

Since the patient has 5 keratosis lesions treated through sanding, 15786 x 5 accurately represents the procedure for each lesion.

Explanation of other options:

A. 15787 x 5: Incorrect because 15787 is designated for dermabrasion of "additional lesions" and would be used in conjunction with 15786, not alone.

B. 15786, 15787: Incorrect, as it does not account for all five lesions treated.

C. 15786, 15787 x 4: Incorrect, as 15787 is used only when performed in addition to 15786, not as a replacement for each additional lesion.

Therefore, the correct answer is D. 15786 x 5, which accurately reports the treatment of all five lesions.