CA05 (2010) - Question E2

Define the following terms:

  • neoplasia,
  • differentiation
  • anaplasia
  • aneuploidy

Curriculum Reference: Introduction To Neoplasms

Again, this assignment question is unchanged from the 2009 version.


Neoplasia is ‘new growth’. 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 stimuli which evoked the change”. Neoplasia may be benign (non-invasive) or malignant (invades other tissues and spreads throughout the body).


Differentiation is the degree to which neoplastic cells resemble their cell of origin, both functionally and morphologically. Less differentiated tumours tend to behave more aggressively and have a poorer prognosis.


Anaplasia describes cells that show no differentiation. Anaplastic features include pleomorphism, abnormal nuclear morphology, increased mitoses, and loss of cellular polarity. Malignant tumours show varying degrees of anaplasia; a synonym for undifferentiated is anaplastic.


Aneuploidy is the presence of too few or too many chromosomes within the nucleus of a cell, relative to the usual number for that cell. It is commonly seen in malignancy due to genomic instability.


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Over to Question E2 from the 2009 version of CA05