Microcystic adnexal carcinoma (MAC) is a rare sweat gland cancer,[1] which often appears as a yellow spot or bump in the skin.

[2] Main treatments are wide local excision or Mohs micrographic surgery, which ensures that most, if not all, cancer cells are removed surgically.

[3] MACs usually present as a smooth, flesh or yellow colored, slow-growing nodule or bump somewhere on the face or neck with typical development being 3–5 years.

[1] Due to the invasive nature of MACs, most cases are treated with wide local excision in order to decrease the rate of reoccurrence.

Increasingly however, Mohs micrographic surgery is being employed as it allows more specific margins to be removed, along with decreasing the size of postoperative scars and disfigurement.