Many times in the news due to the time, space and the lack information, reporters use a single sentence (sometimes followed by one or two more) as the entire story. This is known as a short report. The New York Times, for example, has "North Korean Leader had surgery after stroke, South Koreans say" as one of many short reports, also known as a bulletin. There's is a sense of urgency, "North Korean Leader had surgery after stroke", but no additional information is given except for heresy that South Korean have reported it.
Summary Ledes, similar to short reports, are the opening of a news story and quickly summarize the story. However, unlike short reports, a summary lead has a time element and is in the past tense. Take a look at this one in The Baltimore Sun: "Law enforcement officials today arrested nine people after 18 federal raids that netted heroin, automatic weapons and bags of cash. It was the second major takedown in two days. On Wednesday, officers raided a West Baltimore home and seized seven kilos of heroin, $200,000 in cash and automatic weapons.". It has a time element, "today"(September 11, 2008) and is written in the past tense as you can see by "arrested", "raided", "seized", etc.