Cytology is defined as the study of cells in terms of structure, function and chemistry.

Cytopathology is a branch of pathology that studies and diagnoses diseases on the cellular level. A common application of cytopathology is the Pap smear, used as a screening tool, to detect precancerous cervical lesions and prevent cervical cancer.

Exfoliative Cytology

Cells are extracted from fluid shed into the body cavities. For example in the breast, a nipple discharge may undergo cytological evaluation or in the case of the Pap smear, cells from the cervix.  

Fine Needle Aspiration Cytology 

A needle attached to a syringe is used to aspirate (pull out) cells from lesions or masses in various organs of the body by either free drainage or application of negative pressure (suction). In the setting of the breast it can be performed on lymph nodes in the armpit if required.