Electron microscopic detection of papilloma virus particles in selected koilocytotic cells in a routine cervical smear.

A routine cervical smear from a 56-year-old postmenopausal woman showed appearances indicative of papilloma virus infection with atypia. In an attempt to prove the diagnosis, the smear was reprocessed for electron microscopic examination. The reprocessing technique is described. Ultrastructural preservation was poor, and significant shrinkage was observed. In spite of these technical difficulties it was possible to prove that the selected cells in the smear contained papilloma virus particles. The virus particles seen were intranuclear in location and spherical in shape with a diameter of 40 to 50 nm. As was demonstrated in this case, the technique described will prove useful in evaluating the reliability of various diagnostic criteria for identifying viral infections in routine smears. This will apply particularly in cases where cultural confirmation of a reported viral infection is not possible.