Brown patch on my left knee

i am a 18 years old male, I have had a very large brown patch of skin around my left knee for about a year. It has seem to get larger over time and does not go away, i have tried searching around but nothing seems to be like what i have.  

[Lynminx]

I have something similar to that above my ankle. I went to a dermatologist and he said it's nothing to worry about, as long as it doesn't vary in color, is not raised and doesn't all of a sudden dramatically expand in size. I can't remember what he called it. All I remember is him calling it something and me thinking it sounded like "cappuccino". He told me to be sure to protect it from the sun and to take pictures of it that include my knee and ankle every six months so that I can monitor any changes.

[Bhupinder Kaur, MD]

Hello,
Without examination, confirmation of a diagnosis is tough, but it can be due to hyperpigmentation of the skin. This darkening occurs when an excess of melanin, the brown pigment that produces normal skin color, forms deposits in the skin.

Treatment involves hydroquinone, azelaic acid, corticosteroids, tretinoin cream and laser treatment. Please discuss these options with your dermatologist before using them.
Hope it helps. Take care and please do keep me posted on how you are doing or if you have any additional queries. Kind regards.