Peanut-like mass at the outer edge of the pectoralis major muscle

A mass like peanuts at the lateral edge of the pectoralis major muscle is one of the clinical manifestations of para-breast breast cancer. Parammary breast cancer (mammary of accessory mamma) refers to cancers that occur in the paramammary glands, mostly in the axillary region, and the rare parts are the subclavian region, abdomen, and vulvar region. Wang Faheng (1993) reported 4 cases of para-breast cancer, those with nipples, areola, and mammary glands, and those with only nipples, some with lactation.