Viral infections can be focal and therefore difficult to find by electron microscopy. In addition to sampling limitations, sometimes the only specimen available for examination is tissue that has already been prepared for light microscopy (LM). We have diagnosed a papovavirus infection in skin by embedding hematoxylin and eosin (H&E)-stained sections for ultrathin sectioning and transmission electron microscopy (TEM).
Immunosuppressed patients can have unusual infections or infections in unusual locations. These agents may be difficult to identify due to their not being suspected and incorrect tests being ordered.