occurrence of numerous, relatively small or tiny, fairly well-circumscribed, usually spheroidal portions of tissue that manifest coagulative, caseous, or gummatous necrosis and are characteristically associated with agents that are hematogenously disseminated; frequently observed only in histologic sections, but the foci may be as large as 1-3 mm and macroscopically visible; arbitrarily, foci larger than that are usually not termed focal necrosis.