Respiratory Epithelial Adenomatoid Hamartoma (REAH) in the Olfactory Cleft: Often Masked by Bilateral Nasal Polyps

Respiratory epithelial adenomatoid hamartoma (REAH) is a distinct non-neoplastic entity originating from anterior olfactory cleft in the nasal cavity, often going unnoticed. Clinically, REAH presents as unilateral or bilateral nasal polyps. Our aim is to expand the understanding of bilateral REAH associated with nasal polyposis with respect to clinical, radiological and histopathological features for better clinical outcomes. Our analysis includes patients presenting as bilateral nasal polyps, whose CT-PNS showed opacity in olfactory clefts. During endoscopic sinus surgery, the lesions in the olfactory cleft (medial-to-middle turbinate) were identified and the specimens from olfactory cleft and ethmoid sinus cavity were subjected separately to histopathological analysis. Six patients (average age 50 years, 83% male) of bilateral REAH with nasal obstruction of > 3 years were analysed. On nasal endoscopy, the polypoid masses in the olfactory cleft and in the ethmoids did not show any gross differences. However, polypoidal masses from the olfactory cleft bled more during biopsy and excision. Histopathological study of these masses revealed the closely arranged round to oval glands (with few dilated glands) lined by ciliated columnar epithelium in mildly edematous stroma, confirming the presence of REAH. REAH is an often overlooked lesion in the nasal cavity, arising from olfactory cleft. The presence of nasal polyposis obscures this lesion, resulting in under diagnosis. The prompt identification with high index of suspicion by the otorhinolaryngologists helps in accurate histopathological diagnosis thereby improving clinical outcomes.