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Current English, however, both medical and non-medical, uses tumor as a synonym of neoplasm. Tumor (Latin for swelling, one of the cardinal signs of inflammation) originally meant any form of swelling, neoplastic or not. Therefore, clonality is not required in the definition of neoplasia. It is tempting to define neoplasms as clonal cellular proliferations but the demonstration of clonality is not always possible. The demonstration of clonality is now considered to be necessary to identify a lymphoid cell proliferation as neoplastic. lymphoma and leukemia, clonality is proven by the amplification of a single rearrangement of their immunoglobulin gene (for B cell lesions) or T-cell receptor gene (for T cell lesions). Sometimes, the neoplastic cells all carry the same genetic or epigenetic anomaly that becomes evidence for clonality. These cells are presumed to be clonal - that is, they are descended from a single progenitor cell. Neoplastic tumors often contain more than one type of cell, but their initiation and continued growth is usually dependent on a single population of neoplastic cells. This definition is criticized because some neoplasms, such as nevi, are not progressive. Willis is widely cited: A neoplasm is an abnormal mass of tissue, the growth of which exceeds and is uncoordinated with that of the normal tissues, and persists in the same excessive manner after cessation of the stimulus which evoked the change. Notes: PAS also stains lipofuscin and is more commonly available. Useful to detect demyelinating lesions in the CNS. The definition of the British oncologist R.A. Useful for differentiating brown pigments (melanin, lipofuscin, tattoo pigment, hemosiderin). Secondary neoplasm refers to any of a class of cancerous tumor that is either a metastatic offshoot of a primary tumor, or an apparently unrelated tumor that increases in frequency following certain cancer treatments such as chemotherapy or radiotherapy.īecause neoplasia includes very different diseases, it is difficult to find an all-encompassing definition.They invade and destroy the surrounding tissue, may form metastases and eventually kill the host. Malignant neoplasms are commonly called cancer.They do not invade and destroy but, given enough time, will transform into a cancer.
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Potentially malignant neoplasms include carcinoma in situ.They are circumscribed and localized and do not transform into cancer. Benign neoplasms include uterine fibroids and melanocytic nevi (skin moles).A neoplasm can be benign, potentially malignant ( pre-cancer), or malignant ( cancer).