cyst vs polyp

cyst

noun
  • A pouch or sac without opening, usually membranous and containing morbid matter, which develops in one of the natural cavities or in the substance of an organ. 

  • Of or pertaining to the urinary bladder or gall bladder (in compounds). 

polyp

noun
  • An abnormal growth protruding from a mucous membrane. 

  • A cylindrical coelenterate, such as the hydra, having a mouth surrounded with tentacles. 

How often have the words cyst and polyp occurred in a corpus of books? (source: Google Ngram Viewer )