Steatocystoma multiplex is manifest by multiple clinically palpable skin-colored or yellow nodules scattered on the axillae and the anterior chest wall. Steatocystoma multiplex is included in the differential diagnoses of lipoma, fat necrosis, galactocele, epidermal cyst, and so on, so radiologists need to be aware of its distinguishing features. The findings of a well-circumscribed round fat-density nodule on mammography or an intradermal hypoechoic nodule on sonography, combined with a family history of steatocystoma multiplex (40%) and an extensive bilateral spatial distribution of nodules, confirm the diagnosis of steatocystoma multiplex.