Foci : The medical term applied to a small group of cells occurring in an organ and distinguishable, either in appearance or histochemically, from the surrounding tissue
Heriot-Watt University, School of Life Sciences, Some Terms Used In Toxicology and Chemical Safety, Edinburgh, UK 1992. http://www.who.int/ipcs/publications/methods/harmo nization/en/compilation_nov2001.pdf, (Tox and Chem Sfty - Amer) {85}