instruction: hello doctor I am a 26 year old male I have black brown patches on my back below the neck the whole of my upper back portion has turned black brown it has been around 10 years this discoloration started but is now constant not spreading for the past 5 years
output: hi it is pigmented hairy epidermal nexus becker nexus or backers melanosis the first appearance of this nexus is in adolescence it presents as an irregular hyperpigmented patch once present these neve stabilize after several months or years becker nexus is a benign condition and malignant transformation is rare no treatment is required although lasers have been used for cosmetic benefits its cause is familial and occurs due to mutation genetic counseling should be tried