carcinoma

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Related to lobular carcinoma in situ: invasive lobular carcinoma

neoplasm

neoplasm or tumor, tissue composed of cells that grow in an abnormal way. Normal tissue is growth-limited, i.e., cell reproduction is equal to cell death. Feedback controls limit cell division after a certain number of cells have developed, allowing for tissue repair but not expansion. Tumor cells are less responsive to these restraints and can proliferate to the point where they disrupt tissue architecture, distort the flow of nutrients, and otherwise do damage.

Tumors may be benign or malignant. Benign tumors remain localized as a discrete mass. They may differ appreciably from normal tissue in structure and excessive growth of cells, but are rarely fatal. However, even benign tumors may grow large enough to interfere with normal function. Some benign uterine tumors, which can weigh as much as 50 lb (22.7 kg), displace adjacent organs, causing digestive and reproductive disorders. Benign tumors are usually treated by complete surgical removal. Cells of malignant tumors, i.e., cancers, have characteristics that differ from normal cells in other ways beside cell proliferation. For example, they may be deficient in some specialized functions of the tissues where they originate. Malignant cells are invasive, i.e., they infiltrate surrounding normal tissue; later, malignant cells metastasize, i.e., spread via blood and the lymph system to other sites.

Both benign and malignant tumors are classified according to the type of tissue in which they are found. For example, fibromas are neoplasms of fibrous connective tissue, and melanomas are abnormal growths of pigment (melanin) cells. Malignant tumors originating from epithelial tissue, e.g., in skin, bronchi, and stomach, are termed carcinomas. Malignancies of epithelial glandular tissue such as are found in the breast, prostate, and colon, are known as adenocarcinomas. Malignant growths of connective tissue, e.g., muscle, cartilage, lymph tissue, and bone, are called sarcomas. Lymphomas and leukemias are malignancies arising among the white blood cells. A system has been devised to classify malignant tissue according to the degree of malignancy, from grade 1, barely malignant, to grade 4, highly malignant. In practice it is not always possible to determine the degree of malignancy, and it may be difficult even to determine whether particular tumor tissue is benign or malignant.

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carcinoma

[‚kärs·ən′ō·mə]
(medicine)
A malignant epithelial tumor.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

carcinoma

Pathol
1. any malignant tumour derived from epithelial tissue
2. another name for cancer
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
References in periodicals archive ?
Nor is lobular carcinoma in situ (LCIS) simply a risk factor for invasive breast cancer, as has been the traditional view.
Lobular carcinoma in situ was present in the lactiferous sinuses (hematoxylineosin, original magnification X20).
We also queried institutions with regard to which specific lesions they report margin status for, and the results are summarized in Table 8: 778 of 786 respondents (99%) report margins for IC, 783 of 792 (99%) report margins for DCIS, 455 of 723 (63%) report margins for classical lobular carcinoma in situ (LOS), 635 of 723 (88%) report margins for pleomorphic LCIS, 423 of 723 (59%) report margins for other types of "variant" LCIS, 302 of 723 (42%) report margins for atypical ductal hyperplasia (ADH), and 487 of 723 (67%) report margins for "ADH bordering on DCIS."
In particular, the best course of action for "risk factor" diagnoses like atypical lobular hyperplasia or lobular carcinoma in situ, which constituted most of the findings, is even less clear.
The diagnosis and management of pre-invasive breast disease: pathology of atypical lobular hyperplasia and lobular carcinoma in situ. Breast Cancer Res.
Lobular carcinoma in situ most often involves lobules but may also grow along the basement of extralobular ducts, that is, "pagetoid" growth, and may secondarily involve benign lesions, such as radial scars, papillomas, fibroadenomas, and collagenous spherulosis.
One of the 6 lobular carcinoma in situ cases was pleomorphic type (Figure 1, D through F).
Biopsies that showed atypical ductal hyperplasia, atypical lobular hyperplasia, lobular carcinoma in situ, or flat epithelial atypia were grouped as atypical epithelial lesions.
In Situ Lobular Lesions.--Two variants of lobular carcinoma in situ (LCIS)--pleomorphic lobular carcinoma in situ (Figure 3, A and B) (12) and florid LCIS with central necrosis (Figure 3, C and D) (13)--can mimic high-grade DCIS and low-grade DCIS with central necrosis, respectively.
The atypia category included ADH, apocrine atypia, atypical lobular hyperplasia, and classic lobular carcinoma in situ. The carcinoma category included pleomorphic lobular carcinoma in situ, DCIS, and invasive breast carcinoma.
AAA Versus Pleomorphic Lobular Carcinoma In Situ.--The differential diagnosis of AAA includes, in some cases, pleomorphic lobular carcinoma in situ involving sclerosing adenosis (Figure 8, A through C).