A man was fatally stabbed in the neck early Thursday in the Fifth City neighborhood on the West Side, police said. The 27-year-old was embroiled in a “domestic-related” fight with a 41-year-old man at 12:55 a.m. inside a residential building in the 3500 block of West Fifth Avenue, according to Chicago police. The younger man was stabbed in the neck and taken to Mount Sinai Hospital, police said. He was pronounced dead later that morning. The Cook County medical examiner’s office hasn’t confirmed the death. One person of interest is being questioned, police said.