Studies in animal models have suggested that functional endoscopic sinus surgery may affect facial skeletal growth in children, although reviews of large clinical series do not support this observation. This is a case report of a 12 year old male referred to the senior author (SBL) several months after undergoing bilateral functional endoscopic sinus surgery. The preoperative computed tomograms of the paranasal sinuses were normal with symmetrical well-developed paranasal sinuses. Postoperative computed tomography revealed nearly total involution of the osseous skeleton of the left maxillary sinus. This is the first clinical report of alterations in the facial skeleton of a child secondary to iatrogenic trauma directed at the osteomeatal complex. The case and related literature are reviewed in detail.