Visible-free cholesterol crystal emboli adjacent to microinfarcts in myocardial capillaries and arterioles on H&E-stained frozen sections of an autopsied patient.

The number of released free cholesterol crystal emboli (fCCE) and their role during percutaneous coronary intervention (PCI) in acute coronary syndrome (ACS) have not been documented yet. Furthermore, fCCE manifesting in the coronary lumen following plaque rupture has been historically overlooked owing to the standard tissue preparation for light microscopy which uses ethanol as a dehydrating agent that can dissolve fCCE, leaving behind empty tissue. In this case report, we evaluated fCCE released during PCI for ACS and their relationship with myocardial injury and coronary artery obstruction on the H&E-stained sections by using polarised light microscopy. To our knowledge, there has been no mention of the visibility of fCCE on H&E-stained frozen polarised sections before.