For many health problems, a diagnosis is made by removing a piece of tissue for study in the pathology laboratory. The piece of tissue may be called the sample or specimen. The biopsy report describes what the pathologist finds out about the specimen.
After the specimen is removed from the patient, it's processed as a histologic section or a smear.
Histologic sections. Histologic sections are very thin slices of the specimen that are stained, placed on a glass slide, and then covered with a thin piece of glass called a coverslip. Histologic sections are prepared in one of two ways:
Permanent sections. The specimen is put into a fluid called a fixative for several hours, depending on the specimen type; the fixed specimen is put into a machine which removes the water from the specimen, and replaces it with paraffin wax. The paraffin-impregnated specimen is embedded into a larger section of molten paraffin, and solidified by chilling. A machine called a microtome cuts thin sections of the paraffin block containing the biopsy specimen. The sections are then placed on a glass slide and dipped into a series of stains or dyes to change the color of the tissue. The color makes cells more distinctive when viewed under a microscope.
Frozen sections. The specimen can be examined shortly after it has been removed from the patient. For example, surgical pathologists work closely with the surgeons during surgery for breast cancer. Often, a frozen section is used to determine how much of the breast tissue to remove.
Smears. Smears are done when the specimen is a liquid or there are small, solid chunks suspended in liquid, which are "smeared" onto a slide. They are then allowed to dry or are fixed. The fixed smears are stained, covered with a coverslip, and then examined under a microscope.
A biopsy report describes the findings of a specimen. It contains the following information:
Gross description. A gross description is the obvious examination of the specimen which describes how it looks to the naked eye and where the biopsy was taken from; it may include a description of the color, size, and texture of the specimen.
Microscopic examination. A microscopic examination is a description of what the findings of the slides showed under a microscope; it's usually technical and not in simple language.
Diagnosis. This is usually considered the "bottom line." Although the format varies, often the diagnosis is expressed as: organ or tissue, site from which the biopsy was obtained, type of surgical procedure used to obtain the biopsy, followed by the diagnosis. For example: colon, sigmoid, endoscopic biopsy, tubular adenoma. In other words, the patient had a biopsy of the sigmoid portion of the colon via endoscopy, and a benign tumor of the large intestine and rectum was found.