Medical brain notes 15

  MASTITIS   Mastitis  is an infection of the breast tissue. Acute mastitis  causes an area of erythema and firmness in the breast, commonly   during lactation. The most common infecting organism is  S. aureus . The breast is often biopsied to differentiate the condition from inflammatory carcinoma, another painful breast condition. Microscopically there is acute and chronic inflammation with abscess formation in some cases. Fat necrosis  is often related to trauma or prior surgery, and it may produce a palpable   mass or a discrete lesion with calcifications on mammography. Microscopic changes include fat necrosis, chronic inflammation, hemosiderin deposits and fibrosis with calcification.

  FIBROCYSTIC CHANGES Fibrocystic changes (formerly called  fibrocystic disease ) are a group of very com-mon, benign changes that can be classified as  proliferative  (having an increase in the glandular elements or epithelial cells) or  nonproliferative . Because they carry varying degrees of risk for breast cancer, it is important to identify each type his-tologically. Fibrocystic changes primarily affect women in their reproductive years. The changes most often involve the upper outer quadrant and may produce a palpable mass or nodularity.   •           Fibrosis  may mimic a tumor on clinical exam and U/S.   •           Cysts  can usually be diagnosed by U/S.   •           Apocrine metaplasia  is often seen in cyst walls.   •           Microcalcif...

  BENIGN NEOPLASMS   Fibroadenoma  is the most common benign breast tumor in women age <35. It causes   a palpable, round, movable, rubbery mass, which on cross-section shows small, cleft-like spaces. Microscopically, the mass shows proliferation of benign stroma, ducts, and lobules Phyllodes tumor  (cystosarcoma phyllodes) usually involves an older patient popula-tion (age 50s) and can be benign or malignant. Local recurrence is common but the incidence of metastasis is low. Microscopically, the mass shows increased stromal cellularity, clefts lined by epithelium, stromal overgrowth, and irregular margins. Intraductal papilloma  commonly presents as a bloody nipple discharge. Microscopi-cally, papilloma causes benign papillary growth within lactiferous ducts or sinuses; the myoepithelial layer is preserved.

  MALIGNANT NEOPLASMS Carcinoma of the breast  is the most common cancer in women and affects 1 in 9   women in the United States. It is also the second most common cause of cancer death. The incidence is increasing and is higher in the United States than in Japan. Many risk factors have been identified.   The incidence increases with the following factors:   •           Age   •           Unusually long/intense exposure to estrogens (long length of reproductive life, nulliparity, obesity, exogenous estrogens)   •           Presence of proliferative fibrocystic changes, especially  atypical hyperplasia   •           First-degree relative with breast cancer   Hereditary influences are thought to be involved in 5–10% of  breast cancers, with important genes a...

  GYNECOMASTIA Gynecomastia  is a unilateral or bilateral benign breast enlargement in a male. It is   usually caused by an altered androgen-estrogen balance that favors estrogen effect. Microscopically, it is characterized by:   •           Ductal epithelial hyperplasia   •           Ductal elongation and branching   •           Proliferation of periductal fibroblasts   •           Increase in vascularity in the involved tissue