Concert pianists are a particular breed, fussy about their pianos, especially when they are on tour. Master pianist Eugene Istomin, concerned that some of the smaller cities on his current national tour might not have Steinways, is taking two of the massive concert grands with him.

Obviously, Istomin decided, if rock musicians can take truckloads of complex sound equipment on tour, why couldn't he take the pianos? He chatted with friends at General Motors, who have outfitted a special air-conditioned truck for him, his driver, his pianos and, of course, his own piano tuner. Out and About

A group of New Yorker artists, in town for a 60-year retrospective of the magazine's art that opens at the Corcoran Gallery this week, stopped by the White House yesterday for a visit with President Reagan. The cartoonists, Charles Addams, George Booth, Lee Lorenz and Gretchen Dow Simpson, were autographing the New Yorker cartoon album collection for the president -- Addams drawing Uncle Fester and Booth one of his strange chickens -- when Reagan asked whether they would like to see his private collection of cartoons. He took them to a room off his office where he has on display more than 30 cartoons relating to the 1981 attempt on his life. Seeing that no New Yorker artists were included, Addams promised he would send the president his rendition of the event. Last night, the cartoonists were deluged by fans at a Corcoran reception. Addams even found himself autographing napkins that bore some of his creations. "Everyone from tiny tots to old geezers seems to like my work," he said ...

When the Union Station renewal project opens in September, there will be two major new restaurants there: One, out of Denver, is known as the Rattlesnake Club; the other is a St. Louis steakhouse called Dierdorf & Hart's, owned by former St. Louis Cardinal Dan Dierdorf and former Redskin Jim Hart ...

Frank Sinatra, Sammy Davis Jr. and Dean Martin are getting together in Las Vegas this month to make plans for their upcoming concert tour, which will bring them to Capital Centre March 31. The tour opens next month in Oakland and ends in April at New York's Radio City Music Hall. The aging rat packers will take the summer off and resume the tour in the fall. Tickets for the Washington concert will be available on Feb. 21 ...

More on why controversial rocker Frank Zappa won't be performing next month at the Patriot Center at George Mason University: A Patriot Center official said yesterday that another rock group (INXS) is already scheduled to perform there the same week, and university officials think another concert would be disruptive to the student body. Cellar Door Productions, which represents Zappa, had said it was told that among the reasons for the concert's rejection was the possibility that it would be objectionable to PMRC (Parents Music Resource Center), the group founded by Tipper Gore to alert parents to distasteful rock lyrics. Larry Czarda, George Mason vice president for business affairs, said the university does do its homework on any performer who wants to rent the center and added that while PMRC wasn't the reason for the Zappa rejection, the group may have been mentioned in conversation with Cellar Door. Meanwhile, PMRC, which is in no way affiliated with George Mason and was never involved in the Zappa controversy, was deluged with calls yesterday. A spokesman emphasized that PMRC is a clearinghouse for information about the content of rock concerts and albums, but has never been involved with banning or censoring either ...