The body of Carmine De Santis was found on Monday morning at the roadside close to his hometown of Rovito, Corriere della Sera reported.
His 43-year-old mother, Daniela Falcone, was lying beside the boy with stab wounds inflicted with the same pair of scissors she allegedly used to kill her son, the newspaper said.
The pair had been missing since Saturday after Falcone went to pick the boy up from school, Il Messaggero reported.
Falcone and her husband had reportedly fought the previous night over his alleged affair, during which he admitted to getting another woman pregnant, the newspaper said.
After Falcone failed to return home from school, her husband immediately raised the alarm and police began a full search with a helicopter scouting the nearby mountains.
The child and his mother were not found until an anonymous phone call led them to the pair on Monday.
Police are now waiting for Falcone’s condition to improve before they can question her, Il Messaggero reported.