The year 1955 was an extremely busy one for me. For the first time, I was invited to Europe to give a series of lectures on the topic of cytology. I was also informed that I had to serve in the United States Army to follow the rules of the Doctors' Draft Law instituted by President Harry S. Truman during the Korean War. It took the army nearly 2 years to figure out that my previous military service in the Polish Army in France in 1940 was not sufficient to excuse me from the draft rules because it took place before the attack on Pearl Harbor.

I was also fascinated by cell changes occurring in cervical smears from precancerous lesions. George Papanicolaou, a 3-times-a-week visitor to the laboratory, labeled these abnormal cells “dyskaryotic cells” and failed to notice that some of them had a very unusual appearance. These squamous cells were characterized by enlarged hyperchromatic nuclei surrounded by a clear cytoplasmic zone. None of the other observers paid much attention to this change, but I found it to be of great interest. I wanted to present this information during a forthcoming meeting on cervical pathology that was to take place in May 1955 in New York City.

Working with my invaluable associate technician Grace Durfee, we collected a small number of such cases and information concerning the follow-up. At the same time, I developed an acute back discomfort and spent my time lying on the floor in my apartment with Grace becoming a common visitor who prepared my food and discussed the article.1

The only similarity to these cell changes that I could recall was koilonychias, or “hollow nails.” Because of this similarity, the cell changes observed in the cervical smears were named “koilocytosis.” This was the title under which they were presented in May 1955.

It was subsequently shown2 that koilocytosis is an infection of the squamous cells of the cervix by the papillomavirus, a discovery for which zur Hausen received the Nobel Prize in Physiology or Medicine in 2008.


The author made no disclosures.


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  • 1
    Koss LG, Durfee GR. Unusual patterns of squamous epithelium of the uterine cervix: cytologic and pathologic study of koilocytotic atypia. Ann N Y Acad Sci. 1956; 63: 1245-1261.
  • 2
    zur Hausen H. Human papillomaviruses and their possible role in squamous cell carcinomas. Curr Top Microbiol Immunol. 1977: 78; 1-30.

Leopold G. Koss MD*, * Chair Emeritus, Department of Pathology, Montefiore Medical Center, Bronx, New York