What does anaplasia mean?
Anaplasia is a term from pathology describing the reversion of cells to a more primitive, undifferentiated state — a hallmark of aggressive malignancy. Mature cells normally carry specialized structures and functions that identify them as, say, liver or lung tissue; when anaplasia occurs, those identifying features are lost, and the cells resemble embryonic tissue under the microscope. Pathologists grade tumors partly by their degree of anaplasia: the greater the loss of differentiation, the higher the grade and generally the poorer the prognosis. The word derives from the Greek prefix 'ana-' ('backward') combined with 'plasis' ('formation'), literally meaning a backward formation. Closely related terms include hyperplasia, metaplasia, and dysplasia, which describe other patterns of altered cell growth. Anaplasia is almost exclusively encountered in clinical, research, and educational settings rather than everyday speech.
nounA reversion of cells to a more primitive, undifferentiated form, characteristic of malignant tumors. It is the loss of the specialized structural and functional features that distinguish mature cell types.
- Pathology: the loss of cellular differentiation and reversion to a more primitive form, especially in malignant tumors.
"Under the microscope, the pathologist noted marked anaplasia, a sign of the tumor's aggressive nature."
"The biopsy revealed extensive anaplasia, indicating a high-grade malignancy."
"Tumors exhibiting pronounced anaplasia tend to grow rapidly and resist conventional treatment."
Rarely pluralized in practice; clinicians typically speak of degrees or areas of anaplasia rather than multiple instances.
"The report described foci of anaplasias within several sampled regions of the mass."
In medicine, 'well-differentiated' sounds like praise and 'anaplastic' like doom — because anaplasia means a cell has forgotten what it was supposed to become.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of anaplasia
Anaplasia comes from Greek roots: 'ana-', meaning backward or again, and '-plasia', from 'plassein', to form or mold. It entered English medical usage in the late nineteenth century as pathology developed as a discipline based on microscopic examination of tissues. It shares its root with related pathological terms such as hyperplasia, hypoplasia, metaplasia, and dysplasia, all of which use the same Greek suffix for formation or growth.
How anaplasia is actually used
Strictly a technical term used in pathology, oncology, and medical education; it is rarely encountered outside clinical contexts. The adjective 'anaplastic' describes tumors showing this feature.
Easily confused with anaplasia
Aplasia is the complete failure of an organ or tissue to develop at all, whereas anaplasia is the loss of differentiation in cells that had already matured.
Dysplasia is abnormal but reversible disordered development or growth of cells, while anaplasia is a more severe, irreversible loss of differentiation associated with malignancy.
Metaplasia is the reversible conversion of one differentiated cell type into another, whereas anaplasia is a regression to a primitive, undifferentiated state.