A note from history: landmarks in history of cancer, part 3.

In the early 19th century, microscopy in pathology replaced gross descriptive pathology of the 18th century. Cells became known as the most important and distinct elements of benign and cancerous tissues. Thus, by the mid-1800s, a solid foundation had been laid for microscopy, and surgeons recognized that microscopic diagnosis by pathologists merited attention. In due course, preoperative microscopic diagnoses and classification of cancers in biopsy specimens were incorporated into choosing the most fitting surgical operation.