Anaplasia – dedifferentiation
Hyperplasia – physiological proliferation Increase in number of cells
Neoplasia – abnormal proliferation
Dysplasia – maturation abnormality
Metaplasia – cell type conversion
Prosoplasia – cell type develops new function
Desmoplasia – connective tissue growth
Classification and external resources
ICD-10 C00-D48
ICD-9 140-239.99
DiseasesDB 28841
MedlinePlus 001310.
MeSH D009369
Colectomy specimen containing a malignant neoplasm, namely an invasive colorectal carcinoma (the crater-like, reddish, irregularly-shaped tumor)
Diagram illustrating benign neoplasms, namely fibroids of the uterus

Neoplasm is an abnormal mass of tissue as a result of neoplasia. Neoplasia ("new growth" in Greek) is the abnormal proliferation of cells. The growth of neoplastic cells exceeds and is not coordinated with that of the normal tissues around it. The growth persists in the same excessive manner even after cessation of the stimuli. It usually causes a lump or tumor. Neoplasms may be benign, pre-malignant (carcinoma in situ) or malignant (cancer).

In modern medicine, the term tumor means a neoplasm that has formed a lump. In the past, the term tumor was used differently. Some neoplasms do not cause a lump.



A neoplasm can be benign, potentially malignant (pre-cancer), or malignant (cancer). [1]

Difficulty of definition

Because neoplasia includes very different diseases, it is difficult to find an all-encompassing definition. [2] The definition of the British oncologist R.A. 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.[3]

This definition is criticized because some neoplasms, such as nevi, are not progressive.


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. These cells are presumed to be clonal - that is, they are descended from a single progenitor cell.

Sometimes, the neoplastic cells all carry the same genetic or epigenetic anomaly that becomes evidence for clonality. For lymphoid neoplasms, e.g. 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). The demonstration of clonality is now considered to be necessary to identify a lymphoid cell proliferation as neoplastic.[4]

It is tempting to define neoplasms as clonal cellular proliferations but the demonstration of clonality is not always possible. Therefore, clonality is not required in the definition of neoplasia.

Neoplasia vs. tumor

Tumor (Latin for swelling, one of the cardinal signs of inflammation) originally meant any form of swelling, neoplastic or not. Current English, however, both medical and non-medical, uses tumor as a synonym of neoplasm.[5]

Some neoplasms do not form a tumor. These include leukemia and most forms of carcinoma in situ.

See also


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Look at other dictionaries:

  • neoplasm — NEOPLÁSM, neoplasme, s.n. Formă de cancer caracterizată prin invazia ţesuturilor învecinate, recidivă după o intervenţie chirurgicală; p. gener. cancer. [pr.: ne o ] – Din fr. néoplasme. Trimis de LauraGellner, 13.09.2007. Sursa: DEX 98 … …   Dicționar Român

  • Neoplasm — Ne o*plasm (n[=e] [ o]*pl[a^]z m), n. [See {Neoplasia}.] (Physiol. & Med.) A new formation or tissue, the product of morbid action. [1913 Webster] …   The Collaborative International Dictionary of English

  • neoplasm — neoplasm. См. бластома. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • neoplasm — (n.) 1864, coined in German by Karl Friedrich Burdach (1776 1847) from NEO (Cf. neo ) + Gk. plasma formation (see PLASMA (Cf. plasma)). Related: Neoplastic …   Etymology dictionary

  • neoplasm — *tumor, malignancy, cancer …   New Dictionary of Synonyms

  • neoplasm — [nē′ō plaz΄əm] n. [ NEO + PLASM] an abnormal growth of tissue, as a tumor …   English World dictionary

  • Neoplasm — Literally, a new growth. Neoplasm is another word for a tumor. * * * An abnormal tissue that grows by cellular proliferation more rapidly than normal and continues to grow after the stimuli that initiated the new growth cease. Neoplasms show… …   Medical dictionary

  • neoplasm — noun Etymology: International Scientific Vocabulary Date: 1864 tumor 2 …   New Collegiate Dictionary

  • neoplasm — n.; pl. neoplasia [Gr. neos, new; plasma, formed or molded] An abnormal mass of tissue …   Dictionary of invertebrate zoology

  • neoplasm — neoplastic /nee euh plas tik/, adj. /nee euh plaz euhm/, n. Pathol. a new, often uncontrolled growth of abnormal tissue; tumor. [1860 65; NEO + PLASM] * * * …   Universalium

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