[Frontal sinusitis, mucocele and subperiosteal superolateral orbit abscess].

INTRODUCTION: Periorbital infection following pansinusitis is a rare complication which can lead to irreversible orbital and intracranial consequences. Chandler classified them in 1970. OBSERVATION: An eight-year-old child presented with a subperiosteal superolateral abscess. The initial flu-like syndrome developed into pansinusitis resisting to usual treatment. Palpebral edema and major exophthalmia then appeared requiring CT scan and MRI, which confirmed a subperiosteal abscess. DISCUSSION: A subperiosteal abscess is a serious condition requiring an early diagnosis and a medical or surgical treatment adapted to the severity. Chandler's classification gives the opportunity to adapt management to the infection's gravity. Ethmoiditis may be complicated by periorbital abscesses found usually in the superointernal quadrant. Medical imaging and surgical treatment confirmed a superolateral periorbital abscess and a frontal mucocele. This case illustrates the possibility of communication between frontal sinus and orbital cavity. During frontal sinus infection, pre-existing mucocele may become super-infected and induce a periorbital abscess.