<s>[INST] Hey, I ve had this dark brown, mole-like thing beside the base of my penis, not on it, for as long as I can remember. I m 16 and have never had sex before, it s not tender and it has never itched or anything like that, but should I be worried about it? It s not asymmetrical, it s perfectly round. [/INST] HelloThanks for query. A dark brown swelling at the base of the penis is likely to be Sebaceous Cyst. The skin at the base of the penis is rich in sebaceous glands and hence prone to get more sebaceous cyst due to accumulation of sebum beneath the skin. Normally they fade away without treatment however they need to be treated if increase in size or get infected. Please consult qualified General Surgeon for clinical evaluation and further treatment. If needed it may need to get excised in Toto (Completely along with the sac). Chat Doctor.  </s>