PIK3CA (encoding p110α, the catalytic subunit of PI3K) oncogenic mutations are involved in various types of cancer, such as colorectal cancer, breast cancer, ovarian cancer, hepatocellular carcinoma, and hidradenoma papilliferum (Arafeh & Samuels, 2019; Goto et al., 2017). Here, PIK3CA is linked to papillary hidradenoma.