Definition – What is a biopsy?
Biopsy refers to the removal of tissue, the so-called “biopsy”, from the human body in clinical diagnostics. It is used to examine the removed cell structures under the microscope. This allows initial suspected diagnoses of potential diseases to be confirmed with certainty.
The biopsy is performed by the treating physician in different ways. A needle is inserted into the tissue to be examined from the outside to obtain a tissue sample. The most common type of biopsy is the fine needle biopsy.
It is mainly used to obtain cells from internal organs and tumours. Although the method is very gentle and painless, several thousand cells can be obtained by applying a slight negative pressure. Classically, fine needle biopsy is used for thyroid biopsy.
Other biopsy options include curettage (scraping out the uterus after a miscarriage), punch biopsy, incision biopsy and vacuum biopsy. In addition to these, there are numerous other techniques for performing a biopsy. An invasive biopsy is also possible, in which a skin incision is made beforehand to make the area under investigation more accessible.
The word biopsy translated from the Greek means: to see life (Bios=life; Opsis=seeing). It provides a means of making a reliable diagnosis following a suspected clinical diagnosis. After the actual biopsy is performed, a pathologist receives the tissue samples.
The pathologist examines the cells under the microscope and can then make statements as to whether the tissue is healthy or diseased. This branch of medicine is known as “pathohistology”. For many diseases of the internal organs, a biopsy is meaningful, especially if tumour diseases are suspected.
Only a biopsy can determine with certainty whether the tumour is benign or malignant. On the basis of the fine tissue cell structures, the pathologist not only recognizes whether the cells of the organ are healthy or not, but also which forms of change are involved and which organ they originally came from. In particular in the case of metastases of malignant tumours in other organs, the original tumour can be determined by means of a biopsy.
What forms of biopsy are there?
There are a number of different forms of biopsy. Among the most common forms of biopsy are the A distinction is made between open biopsy forms (sample excision) and minimally invasive biopsy forms. Open biopsy forms include incision and excision biopsies.
Minimally invasive forms of biopsy include punch biopsy, fine needle biopsy and suction biopsy. Incision biopsy refers to the removal of part of a tissue alteration, while excision biopsy refers to the complete removal of a tissue alteration and a small portion of the surrounding tissue. In biopsy punching, punch cylinders are removed from suspicious tissue using a special device.
It is often used for biopsies of the mammary gland and prostate. In a fine needle biopsy, a fine cannula (hollow needle) is punctured through the skin and the tissue sample (biopsy specimen) is taken by means of negative pressure created by an attached syringe. The suction biopsy is performed using a special needle consisting of an outer and an inner needle.
The needle is guided to its destination under computer control and the tissue sample is removed. Often imaging techniques such as ultrasound or computer tomography are used to assist in the various forms of biopsy. This increases the probability that the biopsy specimen contains a sample from the suspect area.
- Incisional biopsy
- Excision biopsy
- Biopsy punch or punch biopsy
- Fine needle biopsy
- Suction biopsy or vacuum biopsy. In an incision biopsy, only part of a suspicious tissue is removed. This type of biopsy is quite accurate, as sufficient characteristic tissue is removed compared to the other types of biopsy.
Depending on where the incision biopsy is to be performed, a local or short anaesthetic is given. The disadvantage is that there is a higher risk of bruising (haematomas) compared to the other forms of biopsy. A biopsy punch, or punch biopsy, is performed with the help of a special device.
It is often performed under ultrasound or X-ray control to achieve a high degree of accuracy and to minimise risks such as injury to neighbouring structures. It is mainly used for biopsies of the mammary gland and prostate, but can also be used for liver biopsies, for example. The biopsy punch removes tissue cylinders from the suspect tissue.
The biopsy is then examined histologically by a pathologist. A fine needle biopsy is used to obtain cells from internal organs. It is performed with a thin needle with a hollow channel in the middle.
It has the advantage that the complication rate is very low. The risks are lower and also a potential carry-over of the tissue (e.g. tumour cells) is minimised. The disadvantage is that the fine tissue assessment is quite difficult, as only little material is obtained.
If there is any uncertainty, another biopsy may have to be performed. A vacuum biopsy, or suction biopsy, is usually only performed if the biopsy cannot be clarified by means of sonographic punch biopsy. It is mainly used for biopsies of the mammary gland and the prostate.
It is characterised by a high degree of accuracy. This means that the tissue that is obtained is highly likely to retain some of the suspect tissue. Usually several pieces of tissue are removed to increase the accuracy.
In a vacuum biopsy the biopsy needle consists of an outer and an inner needle. Before the biopsy, a small skin incision is made through which the biopsy needle is passed. The biopsy needle cuts out a small piece of tissue from the suspicious area. The tissue piece is then sucked into the removal chamber of the outer needle by the vacuum created. Like all biopsies, the piece of tissue is subjected to a fine tissue examination by a pathologist.