Adenofibroma: A benign neoplasm composed of glandular and fibrous tissues, with a relatively large proportion of glands. (Stedman, 25th ed)Phyllodes Tumor: A type of connective tissue neoplasm typically arising from intralobular stroma of the breast. It is characterized by the rapid enlargement of an asymmetric firm mobile mass. Histologically, its leaf-like stromal clefts are lined by EPITHELIAL CELLS. Rare phyllodes tumor of the prostate is also known.Breast Diseases: Pathological processes of the BREAST.Breast Neoplasms: Tumors or cancer of the human BREAST.Ultrasonography, Mammary: Use of ultrasound for imaging the breast. The most frequent application is the diagnosis of neoplasms of the female breast.Breast: In humans, one of the paired regions in the anterior portion of the THORAX. The breasts consist of the MAMMARY GLANDS, the SKIN, the MUSCLES, the ADIPOSE TISSUE, and the CONNECTIVE TISSUES.Ethinyl Estradiol-Norgestrel Combination: ETHINYL ESTRADIOL and NORGESTREL given in fixed proportions. It has proved to be an effective contraceptive (CONTRACEPTIVES, ORAL, COMBINED).Apocrine Glands: Large, branched, specialized sweat glands that empty into the upper portion of a HAIR FOLLICLE instead of directly onto the SKIN.Breast Cyst: A fluid-filled closed cavity or sac that is lined by an EPITHELIUM and found in the BREAST. It may appear as a single large cyst in one breast, multifocal, or bilateral in FIBROCYSTIC BREAST DISEASE.Choristoma: A mass of histologically normal tissue present in an abnormal location.Biopsy, Needle: Removal and examination of tissue obtained through a transdermal needle inserted into the specific region, organ, or tissue being analyzed.Carcinoma, Ductal, Breast: An invasive (infiltrating) CARCINOMA of the mammary ductal system (MAMMARY GLANDS) in the human BREAST.Estriol: A hydroxylated metabolite of ESTRADIOL or ESTRONE that has a hydroxyl group at C3, 16-alpha, and 17-beta position. Estriol is a major urinary estrogen. During PREGNANCY, a large amount of estriol is produced by the PLACENTA. Isomers with inversion of the hydroxyl group or groups are called epiestriol.Mammography: Radiographic examination of the breast.Toxicity Tests, Chronic: Experiments designed to determine the potential toxic effects of a long-term exposure to a chemical or chemicals.Sclerosis: A pathological process consisting of hardening or fibrosis of an anatomical structure, often a vessel or a nerve.Carcinogenicity Tests: Tests to experimentally measure the tumor-producing/cancer cell-producing potency of an agent by administering the agent (e.g., benzanthracenes) and observing the quantity of tumors or the cell transformation developed over a given period of time. The carcinogenicity value is usually measured as milligrams of agent administered per tumor developed. Though this test differs from the DNA-repair and bacterial microsome MUTAGENICITY TESTS, researchers often attempt to correlate the finding of carcinogenicity values and mutagenicity values.Neoplasms, Multiple Primary: Two or more abnormal growths of tissue occurring simultaneously and presumed to be of separate origin. The neoplasms may be histologically the same or different, and may be found in the same or different sites.Carcinoma, Intraductal, Noninfiltrating: A noninvasive (noninfiltrating) carcinoma of the breast characterized by a proliferation of malignant epithelial cells confined to the mammary ducts or lobules, without light-microscopy evidence of invasion through the basement membrane into the surrounding stroma.Papilloma: A circumscribed benign epithelial tumor projecting from the surrounding surface; more precisely, a benign epithelial neoplasm consisting of villous or arborescent outgrowths of fibrovascular stroma covered by neoplastic cells. (Stedman, 25th ed)Metaplasia: A condition in which there is a change of one adult cell type to another similar adult cell type.Biopsy: Removal and pathologic examination of specimens in the form of small pieces of tissue from the living body.Carcinoma, Lobular: A infiltrating (invasive) breast cancer, relatively uncommon, accounting for only 5%-10% of breast tumors in most series. It is often an area of ill-defined thickening in the breast, in contrast to the dominant lump characteristic of ductal carcinoma. It is typically composed of small cells in a linear arrangement with a tendency to grow around ducts and lobules. There is likelihood of axillary nodal involvement with metastasis to meningeal and serosal surfaces. (DeVita Jr et al., Cancer: Principles & Practice of Oncology, 3d ed, p1205)Hyperplasia: An increase in the number of cells in a tissue or organ without tumor formation. It differs from HYPERTROPHY, which is an increase in bulk without an increase in the number of cells.Carcinoma in Situ: A lesion with cytological characteristics associated with invasive carcinoma but the tumor cells are confined to the epithelium of origin, without invasion of the basement membrane.Diagnostic Errors: Incorrect diagnoses after clinical examination or technical diagnostic procedures.Fibroadenoma: An adenoma containing fibrous tissue. It should be differentiated from ADENOFIBROMA which is a tumor composed of connective tissue (fibroma) containing glandular (adeno-) structures. (From Dorland, 27th ed)Biopsy, Fine-Needle: Using fine needles (finer than 22-gauge) to remove tissue or fluid specimens from the living body for examination in the pathology laboratory and for disease diagnosis.Rats, Inbred F344Carcinoma: A malignant neoplasm made up of epithelial cells tending to infiltrate the surrounding tissues and give rise to metastases. It is a histological type of neoplasm but is often wrongly used as a synonym for "cancer." (From Dorland, 27th ed)Neoplasms, Experimental: Experimentally induced new abnormal growth of TISSUES in animals to provide models for studying human neoplasms.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Retrospective Studies: Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.Case-Control Studies: Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.Age Factors: Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from AGING, a physiological process, and TIME FACTORS which refers only to the passage of time.Follow-Up Studies: Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.