I have a pigmented spot located on the back of my thigh, should I be concerned?

Hello…I’m attaching an image of a small pigmented spot which I have, located on the back of my thigh, midway between the buttocks and knee. I noticed it when I was doing a self skin-check, although I believe I recall seeing it there quite a few years ago and looking the same as it currently does. It is light brown/ tan and slightly larger than one quarter of an inch. It is smooth. It is located in the middle of each image.

I do visit a dermatologist twice yearly for skin checks, and no concern was expressed over the spot. Do you have any idea what it could be and whether I should be concerned? Thank you!

Age: 50
Medications: Lexapro, furosemide, potassiam