Cytopathology examines isolated cells which are not in a tissue arrangement.
Such cells can be obtained from:
- excretions
- by scraping them from the surface of an organ
- by suction (aspiration) of fluid from a body cavity
- by suction of the cell material from a solid organ (Fine Needle Aspiration Cytology= FNAC)
Cervical Cytopathology
Cervical cytology, known as the “Pap Smear” is the best known type of cytopathology. George Nicolas Papanicolaou is generally regarded as the father of the cervical (gynaecological) smears. The collected cell material scraped from the uterine cervix can be smeared directly onto the glass slide but can also be rinsed in special preservative liquid and prepared according to the special Liquid Based Cytology method. This latter method has advantages over the conventional method since there are, for example, less erythrocytes, mucus, debris, etc. on the background of the slide, making screening less tedious.
In addition, more samples can be made for additional staining or other techniques, such as detection of Human Papilloma Virus (HPV), which is associated with (pre)neoplastic lesions of the uterine cervix, by PCR or hybridization techniques, or immunocytochemistry for e.g. p16 (dysplasia marker). A disadvantage of the Liquid Based Cytology is that it is more costly than the conventional cervical smear.
The aim of cervical smears made within the framework of population based screening is to diagnose cervical cancer in an early stage or preferable in a preneoplastic stage, when the disease is still completely curable. Cervical smears are also made during follow-up of the patient after her treatment for (pre)cancer to detect new lesions if any.
Non-Cervical Cytopathology
Cytopathology is also applied in the diagnostics of body cavity fluid from the pleura, peritoneum, pericardium, urinary bladder and cerebrospinal fluid.
Fine Needle Aspiration Cytopathology
What it is
Fine Needle Aspiration Cytology (FNAC) has become a widely recognized technique since the last few decades. Cells can be aspirated actively from tumors in nearly all sites of the body, for example lymph nodes, breasts, salivary glands, skin, thyroid, lung, liver, etc. The aspirate can also be used for special stainings to determine hemosiderin pigment, melanin pigment, mucus, glycogen, etc., but also for immunocytochemistry and electron microscopy. Redundant cell material can be processed to histological slides.
Why it is used
Cytopathology makes it possible to predict the probable histological diagnosis with high probability. For malignancies it is often possible to indicate the type of the tumor such as Non-Hodgkin Lymphoma, Hodgkin Lymphoma, adenocarcinoma or a squamous cell carcinoma, etc. In case of infections, the causal agent such as fungi, pneumocystic carinii, etc, can often be determined by morphological, cytochemical, immunocytochcmical or molecular techniques.
Conclusive
The FNAC is in experienced hands (which means that both the aspiration taker and the aspirate interpreter have skills in cellular diagnosis) a minimally invasive, cost-effective, simple, fast and safe technique for the benefit of patient’s care and management.