<pathology> A cell of large size, often with many nuclei. They are multinucleated masses produced by the fusion of many cells.

They are often associated with viral infections. In AIDS, they are induced when the envelope glycoprotein of HIV binds to the CD4 antigen of uninfected neighboring T4 cells. The resulting syncytium leads to cell death and thus may account for the cytopathic effect of the virus.

(18 Jul 2002)