Biopsy

A biopsy is a type of surgery in which some tissue is removed from a patient for examination. This is usually to measure the extent or the presence of a disease. The removed tissue can be examined in different ways, but it is usually looked at under a microscope by a pathologist. The tissue can also be analyzed chemically. There are also different methods of removing tissue for examination. When an entire portion of the tissue affected by the disease is removed, it is called an excisional biopsy. When only part of the affected tissue is removed for examination, it is called a core biopsy or incisional biopsy.

Image source

• Wikipedia: biopsy
• Mayo Clinic: Types of biopsy procedures used to diagnose cancer