1. INTRODUCTIONThe paranasal sinuses include the ethmoid, frontal, sphenoid, and maxillary sinuses. These air-filled spaces in the maxillofacial and skull area are lined with mucosa and communicate with the nasal cavity (1). The maxillary sinuses start developing in the third month of intrauterine life, making them the first paranasal sinuses to develop in the human fetus (2). They continue to grow until puberty. The maxillary sinus typically has an average volume of 6-8 cm³, making it the largest paranasal sinus, though its size varies with age (3).Maxillary sinus aplasia (MSA) is a condition characterized by the absence of sinus development. This rare condition is often asymptomatic but can sometimes present as facial pain or headaches. Typically diagnosed incidentally during radiological procedures for other purposes, such as dental implants, MSA shows no gender or geographical predilection and can occur worldwide (4). MSA may occur in isolation or be associated with broader craniofacial syndromes like cleft palate, Crouzon syndrome, or Apert syndrome. While many individuals with MSA are asymptomatic, those with symptoms may experience nasal obstruction, sinus infections, or facial pain (5). Symptomatic management focuses on addressing related nasal or sinus issues, and surgical intervention is rarely needed, reserved only for specific complications or associated craniofacial abnormalities (6). Hypoplasia of the inferior concha and the absence of the infundibulum and uncinate process are rare anatomical variations that can significantly impact clinical outcomes, particularly in cases of MSA or other sinus anomalies (7). Often discovered incidentally during imaging, these conditions can be asymptomatic but may sometimes present with sinonasal symptoms like nasal obstruction or chronic sinusitis. Case reports highlight the association of these anomalies with impaired sinus function and recurrent infections, necessitating careful evaluation and tailored management strategies (8).Maxillary sinus hypoplasia (MSH) refers to the underdevelopment of the maxillary sinuses, where the sinus is present but smaller than normal. This condition can affect individuals of any age and gender and is often discovered incidentally (9). Symptomatic individuals may experience chronic or recurrent sinus infections, nasal obstruction, or facial pain, particularly in the cheek area. MSH can also be associated with other craniofacial anomalies or developmental conditions like cleft palate and craniosynostosis syndromes (10). MSH is classified into three types according to Bolger’s classification: Type I (mild hypoplasia), Type II (significant hypoplasia with an absent uncinate process), and Type III (profound hypoplasia with an absent uncinate process). CT scans are the gold standard for diagnosing MSH and MSA, with MRI also being useful (11). Symptomatic cases are treated with medical management, including antibiotics, nasal decongestants, and corticosteroids (9). For chronic or recurrent sinusitis unresponsive to medical treatment, functional endoscopic sinus surgery (FESS) may be considered to improve sinus drainage and ventilation. Asymptomatic cases do not require treatment. An incidental finding of unilateral maxillary sinus aplasia was reported during a radiographic examination (8, 9). We report an incidental finding of unilateral aplasia of the maxillary sinus during a radiographic examination.
