Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Microcystic adnexal carcinoma ?
    ### Response:
    Microcystic adnexal carcinoma is a rare tumor of the skin that most often develops in the head and neck region, particularly in the middle of the face, though it may occur in the skin of other parts of the body as well.  The average age of diagnosis is 56.  This tumor is often first noticed as a bump or yellowish spot in the skin.
    