Epithelioid macrophage is an activated macrophage that resembles an epithelial cell with finely granular, pale eosinophilic cytoplasm and central, ovoid nucleus (oval or elongate). This cell type is able to merge into one another to form aggregates. The presence of such aggregates may characterize some pathologic conditions, mainly granulomatous inflammation. [ http://www.ncbi.nlm.nih.gov/pubmed/12673090 MESH:D015622 ]