Primary Cutaneous Adenoid Cystic Carcinoma: A Misdiagnosed Tumor.

Primary cutaneous adenoid cystic carcinoma (PCACC) is a rare, slow-growing adnexal skin tumor with about 250 documented cases. We present a case involving a 66-year-old woman who was treated with ovulation inductors 30 years ago and underwent surgeries for meningioma 20 years ago and invasive galactophoric adenocarcinoma of the left breast 12 years ago. She presented with a gradually enlarging, solid, skin-colored tumor on her scalp, located along an old surgical scar initially diagnosed as a keloid by her surgeon.