A two-alarm fire burned for two hours in a large house in Potomac yesterday, injuring 38 Montgomery County firefighters and causing damage estimated at hundreds of thousands of dollars before it was controlled, county fire officials said.

Officials said no one was in the house at 10601 Bit & Spur La., the residence of Dr. Dominic E. Sabatini, chief of radiology at the Washington Hospital Center, when the fire was reported about 5 p.m. About 50 firefighters from four county fire districts responded to the blaze.

Fire officials said 23 of the injured firefighters were treated at the scene for minor burns and heat exhaustion. Ten firefighters suffering from similar injuries or smoke exhaustion were taken to Suburban Hospital, and five others were taken to Shady Grove Adventist Hospital, officials said.

Fire officials said an exact damage estimate was unavailable, and the cause of the fire was under investigation.

A neighbor described the house as "like a mansion" and said the fire apparently spread from the garage area and consumed most of the structure.

The neighbor said the Sabatinis said they had left the house to run an errand shortly before the fire broke out. They returned a half hour later and found that "the flames were coming out of the roof like a volcano," the neighbor said.