Benign to malignant transformation

Certain benign neoplasms are prone to undergo malignant changes, and it is important, for both treatment and prognosis, to realise when this occurs. Some or all of the following changes may be recognised:

  increase in size: comparatively rapid enlargement is always suspicious, e.g. a neurofibroma which is becoming sarcomatous;

  increased vascularity: dilated cutaneous veins, ulceration and bleeding in the case of a superficial growth (e.g. melanoma);

fixity: due to invasion of surrounding structures;

involvement of adjacent structures: e.g. facial palsy sug­gests malignant change in an otherwise longstanding parotid pleomorphic adenoma;

dissemination: discovery of secondary deposits.