Cafe au lait

This is a flat, hyperpigmented patch of skin with a clearly demarcated border. The patches are light brown, and often darken with sun exposure.

They are usually present at birth but some appear in the first couple of years of life. They are associated with other conditions including: neurofibromatosis; McCune-Albright syndrome; Noonan syndrome; Bloom syndrome; and Russell-Silver syndrome. Most commonly however, cafe-au-lait macules are isolated findings, and in these cases they appear as single lesions. 

References

https://dermnetnz.org/topics/cafe-au-lait-macule/

https://www.dermatologyadvisor.com/home/decision-support-in-medicine/dermatology/cafe-au-lait-macules/