Oncological neoplasms of the breast are among the most common diseases in women, however, they also occur in men. Breast tumors are usually epithelial of ductal or lobular origin. They can be of different types: Ductal carcinoma in situ (DCIS) Ductal carcinoma in situ is a non-invasive breast tumor whose localization is limited to the inside of the ducts of the breast. Due to the mass screening, nowadays this disease is identified very often. This type of tumor can proceed in three stages (1-3) according to the characteristics of the nuclei in the cells. In stage one and two, tumor cells grow relatively slowly and the risk of recurrence is lower than in women in stage three. Lobular carcinoma in situ Lobular carcinoma in situ (LCIS) arises from the lobule at the terminal part of the duct. In most cases, this tumor cannot be palpated because of its diffuse distribution in the tissues. It is not malignant and occurs most often in women aged 40-50. Invasive Ductal Carcinoma Invasive ductal carcinoma is the most commonly diagnosed breast tumor. It tends to metastasize via the lymphatics. The only specific histological finding of this carcinoma is the invasion of cells through the basement membrane of the thoracic duct. Invasive lobular carcinoma Invasive lobular carcinoma is a less common multifocal disease that usually metastasizes via the lymphatic route. Histologically, tumor cells are arranged in a specific manner. Medullary Carcinoma Medullary carcinomas are more common among younger women. A predisposing factor for this oncological disease is a mutation in the BRCA1 gene. Mucinous (colloid) carcinoma Mucinous carcinoma, also called colloid, is another rare histologic type of tumor that occurs in less than 5% of invasive breast cancers. It usually appears at the age of 70, which on a mammogram looks like an ill-defined tumor with rare calcifications. Mucin production is its histological hallmark. It has two main forms – A and B. Mucinous carcinoma type A is the classic variety with larger amounts of extracellular mucin. Type B is a variant with characteristic endocrine differentiation, histologically showing a more granular cytoplasm. Tubular carcinoma Tubular carcinoma is a very rare disease. It accounts for 1-2% of all breast cancers. His prognosis is good. Papillary carcinoma Papillary carcinoma is a rare disease 1-2% of cases, in women over 60 years of age. There are two types – a cystic non-invasive form and micropapillary ductal carcinoma, which is invasive. Papillary carcinoma is centrally located in the breast and may present as nipple discharge. Metaplastic breast cancer (MBC) Metaplastic breast cancer (MBC) accounts for less than 1% of cases and usually occurs in older women – around age 60. It is adenocarcinoma,in which mesenchymal and epithelial components can be found. Philodes tumors Philodes tumors are very rare – less than 1%. Their name derives from the characteristic leaf-like growth of the cells. This type of tumors can be benign, borderline or malignant. Mammary Paget’s disease (MPD) Paget’s disease of the mammary gland is rare – 1-4% of all cases – affecting people aged around 60 years. This adenocarcinoma is located in the epidermis at the border between the nipple and its areola. It consists of specific Paget cells located in the basement membrane. They are large, pale epithelial cells with hyperchromatic, atypical nuclei that are scattered among the keratinocytes singly or as a cluster of cells. Inflammatory breast cancer Inflammatory breast cancer is an extremely aggressive local tumor disease. It is rare – 1-5%. Because of its aggressive nature, distant metastases are frequent, especially in the lymph nodes. It is characterized by diffuse erythema and edema that covers one third or more of the skin of the breast. Sources: https://emedicine.medscape.com/article/1954658-overview#showall