Antrochoanal polyp (ACP) is a benign unilateral polyp, originating from the maxillary sinus and expanding through the accessory or natural ostia into the nasal cavity and choanae. It has a 2: 1 male predominance and is more common in children and young adults. The exact pathophysiology is unclear, and it is thought to have less of the inflammatory reactions as opposed to typical bilateral nasal polyps which are commonly seen in diffused chronic rhinosinusitis. The presenting symptoms of ACP are unilateral nasal obstruction and rhinitis. Epistaxis, pain, and foul-smelling secretions are not typically seen and point towards a different etiology. Diagnosis is mainly clinical via endoscopic examination and supported by Computed tomography (CT) imaging. In CT images the three components of the polyp can be identified; an intramaxillary portion, intranasal and choanal components. Treatment is surgical, where Endoscopic sinus surgery (ESS) is the main technique used with other assisting approaches to reach the more challenging anterior and inferior areas of the maxillary sinus. Successful resection depends on complete removal of the intramaxillary component of the polyp to avoid polyp regrowth. The typical histologic characteristics are cyst formation, fibrosis and squamous metaplasia that are significantly more common in ACP than diffused nasal polyps.
Part of the book: Pathology