A rare complication of frontal sinusitis includes Pott's puffy tumor. It manifests as a swelling of the forehead due to the presence of a subperiosteal abscess secondary to osteomyelitis of the frontal bone. A timely diagnosis allows for an early, intensive medical and surgical treatment, which is critical to prevent serious intracranial complications. Here we describe the case of a 12-year-old boy with Pott's puffy tumor as a complication of pansinusitis. This case was a diagnostic challenge; however, a timely treatment allowed for a favorable clinical course.