Difficulty of Definition
Because neoplasia includes very different diseases, it is difficult to find an all-encompassing definition. 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." This definition is criticized because some neoplasms, such as nevi, are not progressive.
Read more about this topic: Secondary Neoplasm
Famous quotes containing the words difficulty of, difficulty and/or definition:
“... the only way in which Mr. Brooke could be coerced into thinking of the right arguments at the right time was to be well plied with them till they took up all the room in his brain. But here there was the difficulty of finding room, so many things having been taken in beforehand. Mr. Brooke himself observed that his ideas stood rather in his way when he was speaking.”
—George Eliot [Mary Ann (or Marian)
“The more difficulty there is in creating good men, the more they are used when they come.”
—Ralph Waldo Emerson (1803–1882)
“Scientific method is the way to truth, but it affords, even in
principle, no unique definition of truth. Any so-called pragmatic
definition of truth is doomed to failure equally.”
—Willard Van Orman Quine (b. 1908)