An über rare–50 cases in the world literature–cardiac lesion* consisting of an aggregate of mesothelial and monocytic cells and other inflammatory cells, adipocytes, and fibrin. MICE develops in a background of cardiac manipulation–e.g., valve replacement, cardiac catheterisation, inflammation, mechanic or tumour stimulation. It is histologically similar to nodular histiocytic/mesothelial hyperplasia–NHMH, a well-described reactive response that occurs in the pericardium, pleura, peritoneum, and pelvis.
*MICE is an acronym for mesothelial/monocytic incidental cardiac excrescences
Reference J Clin Pathol 2010;63:853-855 doi:10.1136/jcp.2010.080259