Respiratory Epithelial Adenomatoid Hamartoma Characteristics of Extra-Olfactory Cleft Disease

Respiratory epithelial adenomatoid hamartoma (REAH) is an under-recognized, nonneoplastic entity of uncertain etiology that occurs in isolation or in chronic rhinosinusitis (CRS). Our goal is to evaluate a single institutional experience with REAH over 15 years and characterize and compare olfactory cleft (OC) REAH and extra-OC REAH.

Retrospective review of pathology-confirmed REAH at a single institution from2009 to 2024. Charts and imaging were reviewed to characterize presentation and outcomes.

REAH was present in 88 patients who were 58.6 ± 15.6 years of age, 58% (n = 51) male, and 75% (n = 66) white. OC-REAH was diagnosed in 49 (55.7%) patients, and extra-OC REAH in 39 (44.3%) patients. Patients with OC-REAH were older (63.2 ± 12.4 years vs. 52.8 ± 17.4 years, p = 0.002) and had higher rates of comorbid allergic rhinitis (67.3% vs. 33.3%, p = 0.002), asthma (55.1% vs. 25.6%, p = 0.005), and prior endoscopic sinus surgery (65.3% vs. 43.6%, p = 0.04) when compared to extra-OC REAH. Fourteen patients with extra-OC REAH presented as a sinonasal mass that was located within the nasal cavity (n = 7, 50%), the maxillary sinus (n = 3, 21.4%), the middle meatus/ethmoid sinus (n = 3, 21.4%), and the sphenoid sinus (n = 1, 7.1%). Three patients with extra-OC REAH had REAH diagnosed in the setting of inverted papilloma. No patients had recurrence on surveillance endoscopy or imaging.

REAH is a benign, incompletely understood entity with variable presentation. Patients with OC involvement are older, with higher rates of allergic rhinitis and asthma compared to those with no OC involvement. REAH can rarely present as a discrete mass sparing the OC, mimicking other sinonasal pathology.