Pathology

病理学

Most breast cancers are epithelial tumors that develop from cells lining ducts or lobules; less common are nonepithelial cancers of the supporting stroma (angiosarcoma, primary stromal sarcomas, phyllodes tumor). Cancers are divided into carcinoma in situ and invasive cancer.

多数乳腺癌属上皮细胞瘤，由乳腺管或小叶内膜细胞发展而来，少数是支撑间质的非上皮癌（血管肉瘤、原发性间质肉瘤、叶状肿瘤)。乳腺癌分原位癌和浸润性癌。

Carcinoma in situ is proliferation of cancer cells within ducts or lobules and without invasion of stromal tissue. Usually, ductal carcinoma in situ (DCIS) is detected only by mammography and is localized to one area; it may become invasive. Lobular carcinoma in situ (LCIS) is a nonpalpable lesion usually discovered via biopsy; it is rarely visualized with mammography. LCIS is not malignant, but its presence indicates increased risk of subsequent invasive carcinoma in either breast; about 1 to 2% of patients with LCIS develop cancer annually.医学.全在线www.med126.com

原位癌为乳腺管或小叶内的癌细胞增生，无间质组织的浸润。通常，原位管癌（DCIS)只有通过乳房X线照相才能发现，并局限于某个部位，可以发展为浸润性。原位小叶癌（LCIS)为一触摸不到的病变，通常经由组织活检发现，鲜少被乳房X线照相发现。LCIS不属恶性，但它的出现表明一侧乳房发生浸润性癌的危险增加了。每年约有1－2%的LCIS病人发展为乳腺癌。

Invasive carcinoma is primarily adenocarcinoma. About 80% is the infiltrating ductal type; most of the remainder is infiltrating lobular. Rare forms include medullary, mucinous, and tubular carcinomas.

浸润性癌主要是腺瘤，80%左右为浸润性导管型，剩下的大多为浸润性小叶癌。罕见类型包括髓样、粘蛋白样与管状癌。

Paget's disease of the nipple (not to be confused with the metabolic bone disease also called Paget's disease) is a form of ductal carcinoma in situ that extends into the overlying skin of the nipple and areola, manifesting with an inflammatory skin lesion. Characteristic malignant cells called Paget cells are present in the epidermis. The cancer may be in situ or invasive.

乳头偑吉特病（不要与同名的“偑吉特病”变形性骨炎混淆)是一种原位管癌，它扩展到乳头上面的皮肤和乳晕，呈现炎症性皮肤病变症状。它特有的恶性细胞称为偑吉特细胞，存在于上皮中。乳头偑吉特病可能是原位性，也可能是浸润性。

Breast cancer invades locally and spreads initially through the regional lymph nodes, bloodstream, or both. Metastatic breast cancer may affect almost any organ in the body—most commonly, lungs, liver, bone, brain, and skin. Most skin metastases occur in the region of the breast surgery; scalp metastases also are common. Metastatic breast cancer frequently appears years or decades after initial diagnosis and treatment.

乳腺癌局部浸润，最初经由局部淋巴结、血流或两者扩散。转移性乳腺癌几乎可以影响肌体的任何器官，并以肺、肝、骨、大脑和皮肤为最常见。多数皮肤转移发生在乳房手术部位，头皮转移也较常见。乳腺癌转移经常在初始诊断治疗几年或几十年之后出现。

Estrogen and progesterone receptors, present in some breast cancers, are nuclear hormone receptors that promote DNA replication and cell division when they are bound to the appropriate hormones. Thus, drugs that block these receptors may be useful in treating tumors with the receptors. About 2⁄3 of postmenopausal patients have an estrogen-receptor positive (ER+) tumor. Incidence of ER+ tumors is lower among premenopausal patients. Another cellular receptor is human epidermal growth factor receptor 2 (HER2) protein; its presence correlates with a poorer prognosis at any given stage of cancer.

有些乳腺癌带有雌激素和孕酮受体，他们都是细胞核激素受体，与适当激素结合时就会促进DNA复制和细胞分裂，因此，用受体阻断药物治疗含有这些受体的肿瘤是有用的。约2/3的绝经后病人带有雌激素受体阳性（ER＋)肿瘤。绝经前病人的ER＋肿瘤发病率较低。另一个细胞受体是人表皮生长因子受体2（HER2)蛋白，它的存在与已知癌症期预后不良有关。

Symptoms and Signs

症状体征

Most breast cancers are discovered as a lump by the patient or during routine physical examination or mammography. Less commonly, the presenting symptom is breast pain or enlargement or a nondescript thickening in the breast. Paget's disease of the nipple presents with skin changes, including erythema, crusting, scaling, and discharge; these usually appear so benign that the patient ignores them, delaying diagnosis for a year or more. About 50% of patients with Paget's disease of the nipple have a palpable mass at presentation. A few patients with breast cancer present with signs of metastatic disease (eg, pathologic fracture, pulmonary dysfunction).

多数乳腺癌是在病人自检、常规体检或乳房X线照相时发现的，它只是一个肿块。出现乳房疼痛或增大、或乳房莫名增厚等情况较少见。乳头偑吉特病的特征是皮肤改变，包括红斑、结皮、结鳞和出现分泌物等。表面上为良性，以至常被病人忽略，使诊断延误一年或更久。约50%的乳头偑吉特病患者在就诊时有可触摸到的肿块。有些乳腺癌患者呈现转移性疾病（如病理性骨折、肺功能障碍)。

A common finding during physical examination is a dominant mass—a lump distinctly different from the surrounding breast tissue. Diffuse fibrotic changes in a quadrant of the breast, usually the upper outer quadrant, are more characteristic of benign disorders; a slightly firmer thickening in one breast but not the other may be a sign of cancer. More advanced breast cancers are characterized by fixation of the lump to the chest wall or to overlying skin, by satellite nodules or ulcers in the skin, or by exaggeration of the usual skin markings resulting from lymphedema (so-called peau d'orange). Matted or fixed axillary lymph nodes suggest tumor spread, as does supraclavicular or infraclavicular lymphadenopathy. Inflammatory breast cancer is characterized by diffuse inflammation and enlargement of the breast, often without a lump, and has a particularly aggressive course.

体检时通常发现的是一明显肿块，明显不同于周围乳房组织。乳房某一象限的弥散性纤维性变化，通常在上外侧，其良性特征更明显。一侧乳房出现稍硬的增厚，另一侧没有，这种情况就有可能是癌的症状。较晚期乳腺癌的特点是肿块固定在胸壁或上皮、皮肤出现卫星结节或溃疡，或通常的皮肤纹理因淋巴水肿出现扩大（所谓的桔皮状皮肤)。表面粗糙或固定腋淋巴结提示肿瘤扩散，如锁骨上或锁骨下淋巴结病变。炎性乳腺癌的特点是乳房的弥漫性炎症和增大，常常没有肿块，具有特殊的侵略性过程。