An 84-year-old woman was revealed to have focal asymmetric density(FAD)based on mammography, and ultrasonography showed a 0.5 cm sized cyst in the left breast. It gradually increased in size and contained solid components. A core needle biopsy revealed an intracystic papillary carcinoma of the breast. Partial mastectomy and sentinel lymph node biopsy were performed. Histopathological examination revealed an encapsulated papillary carcinoma and a papillary lesion surrounded by a thick fibrous capsule. Myoepithelial cells were not found at the periphery of the lesion or within fibrovascular cores. Currently, it is classified as non-invasive carcinoma, and the patient has a good prognosis.