Fibroadenoma is the most common breast tumor in adolescent and young women. Fibroadenomas that consist of sclerosing adenosis, papillary apocrine metaplasia, epithelial calcifications, and/or cysts greater than 3 mm are considered as complex fibroadenoma. The relative risk of developing breast cancer in patients with complex fibroadenoma is increased, compared to women with noncomplex fibroadenoma. Extensive cystic degeneration in a fibroadenoma, so called “cystic fibroadenoma” is very rare. Herein, we present a case of such a lesion in a 43-year-old female who has been on follow-up for fibrocystic changes of the breast, and discuss both radiological and histopathologic differential diagnosis of this lesion with other cystic lesions of the breast, including cystic papilloma. The patient is free of disease after 17 months of clinical follow-up.