Pap test
The Pap test or Papanicolaou test is the microscopic examination of cells in a cell swab from the cervix for the early or early detection of cancer and its preliminary stages. The Pap test was developed by the Greek doctor George Papanicolaou and introduced in 1928. It is based on an assessment of stained cell smears from the cervix and is used for early detection of cervical cancer .
By means of a cotton swab (preferably with a specially designed spatula, the so-called Szalay spatula corresponds to which of the specific shape of the vaginal portion, or a small brush) are obtained from the cervix (spatula for portio and brush for cervical removed) cells and on a slide streaked . After fixation with 96% alcohol, staining is carried out using hematoxylin according to Harris and Orange G and, according to an ascending alcohol series, using a special staining solution (various modifications).
The morphology of the cells can now be assessed microscopically in the colored smear. Conclusions can be drawn about the hormone status (see vaginal cytology ) and the cycle phase (differentiation of the vaginal plate and cervicoendometrial epithelium), inflammation (granulocytes) as well as cancer precursors and cervical cancer can be detected. Furthermore, indications of infections can be found, e.g. B. milk glass cores in herpes, koilocytes (florid) with strongly pronounced HPV infection, paranuclear vacuoles with multiple small reddish inclusion in chlamydia (covered squamous from Intermediärzelltyp that of tightly packed short basophilic rods), Clue cells with Gardnerella vaginalis and yeast cells of candida .
cytology
The cells of the outer cervix consist of several layer, unverhorntem plates epithelium . They can be due to its appearance of the cells of the cervical canal, which with epithelium is covered delimit. The squamous cells can in turn be subdivided. Cells in the top layer of cells are called superficial cells. These are 45 to 60 µm in size. Your cytoplasm has a delicate pink color. The cell itself is polygonal in shape. The nucleus is normally very small at 5 to 7 µm compared to the area of the cell plasma. The chromatin in the core is tightly packed. This results in a deep blue coloration of the cell nuclei. In the first phase of the cycle, the superficial cells make up the majority of the cells visible in the smear, since in this phase the squamous epithelium proliferates under the influence of estrogen .
Deeper squamous cells are called small and large intermediate cells. Like the superficial cells, the large intermediate cells have a polygonal shape. They are the same size as the superficial cells. However, their cytoplasm is very rich in glycogen , which is why it is light blue-green (cyanophilic) in color. The cores are up to 10 µm in size. Their chromatin is somewhat loosely packed than the core content of the more superficial cells. The large intermediate cells make up the majority of the visible cells in the second half of the cycle due to the influence of the progestin . Small superficial cells are cells with an equally delicate blue-green plasma. However, they are smaller and have a larger core. The cells are rounded in shape. They can occur more frequently with long-term use of a contraceptive , menopause and hormonal disorders. The nucleus also contains very small cells with a large nucleus and little cytoplasm, which are part of the squamous epithelium. These so-called parabasal cells cannot be adequately assessed with a light microscope. However, they are the stem cells of the squamous epithelium from which superficial and intermediate cells are derived.
The columnar epithelium on the inner side of the cervix can be divided into two cell groups in the PAP smear. The much more common mature columnar epithelial cells with small nuclei, blue plasma and sometimes also fimbriae show structures that are reminiscent of honeycombs or palisades, depending on the incision. The cells are mechanically very vulnerable and can be destroyed when the swab is taken and the material is processed. Your cell debris will then be visible under the microscope. The stem cells of the columnar epithelium are called reserve cells. They are difficult to assess with a light microscope. Some of the stem cells are still pluripotent . Stem cells of the columnar epithelium are the starting point for the physiological metaplasia on the outside of the cervix. They are also the starting point for cervical cancer .
The findings are classified into "groups" according to Munich nomenclature III, particularly with regard to cervical cancer diagnosis:
| Pap 0 | Insufficient cell smear |
| Pap I | Normal findings, normal |
| Pap II | Findings with limited protective value |
| Pap III | Unclear or doubtful findings |
| Pap IIID | Dysplasia findings with greater tendency to regression |
| Pap IV | Immediate preliminary stages of cervical cancer |
| Pap V | Malignancies |
As with any medical test, there are false positive and false negative test results. A study on the informative value of the Pap smear showed a sensitivity (the ability to recognize sick people as sick) of only about 51% and a specificity (the ability to recognize healthy people as healthy) of about 98%. It is therefore recommended to have the Pap test carried out once or twice a year. It is only through frequent repetition that this test is safe. With an annual decrease, for example, the sensitivity increases to around 90% after 3 years.
The cytology is a technical advancement in the preparation of cells taken in the context of Pap tests.
history
George Nicolas Papanicolaou carried out the fundamental research between 1923 and 1943; he first published it in 1928 in his essay New Cancer Diagnosis as part of the Battle Creek Med. Conference (January 2-6).
The incidence of cervical cancer was significantly reduced as a result of the introduction of the Pap test into gynecological practice, and mortality from cervical cancer decreased by two thirds.
literature
- Georgios Papanikolaou: New Cancer Diagnosis. In: Proceedings of the third Race Betterment Conference, January 2-6, 1928. Race Betterment Foundation, Battle Creek MI 1928, pp. 528-534.
- Richard Mac DeMay: The pap test. ASCP Press, Chicago IL 2005, ISBN 0-89189-420-9 .
Web links
- Frank W, Konta B, Peters-Engel C: PAP test for screening for cervical cancer . (PDF; 355 kB) DAHTA @ DIMDI , 2005
Individual evidence
- ↑ a b c Hellmut Flenker: Pocket Atlas of Gynecological Cytology. 2nd, expanded edition. IDwerk, Bremen 2004, ISBN 3-00-013458-1 , pp. 36–47.
- ^ Henrik Griesser, Katrin Marquardt, Bodo Jordan, Wolfgang Kühn, Klaus Neis, Heinrich H. Neumann, Reinhard Bollmann, Birgit Pöschel, Manfred Steiner, Ulrich Schenck: Gynecological cytodiagnostics of the cervix: Münchner Nomenclature III. ( Memento of November 29, 2014 in the Internet Archive ) (PDF). In: Gynecologist. Vol. 54, No. 11, 2013, pp. 1042-1048.
- ↑ Joël Coste, Béatrix Cochand-Priollet, Patricia de Cremoux, Catherine Le Galès, Isabelle Cartier, Vincent Molinié, Sylvain Labbé, Marie-Cécile Vacher-Lavenu, Philippe Vielh: Cross sectional study of conventional cervical smear, monolayer cytology, and human papillomavirus DNA testing for cervical cancer screening. In: The BMJ . Vol. 326, No. 7392, 2003, pp. 733-736.
- ↑ PAP test (cancer smear) accessed on January 15, 2015.
