It is the Castilianization and pronunciation of the Greek surname Papanicolaou. Surname of a Greek Physician named Georgios N. Papanikolaou, precursor in Cytopathology. In Medicine and Gynecology it is a type of test that allows to determine problems in the cervix. It serves to early discover cancer in the cervix. It is also called vaginal cytology.
Although used, it is a papanicolaou error. ( As there is a gynecological examination popularized with that name, surely for convenience of pronunciation it will be castanized as well. But I would respect the transliterated version of Greek. )
It's a medical procedure to detect cancer for women