Respiratory epithelial adenomatoid hamartoma: a review

Abstract

Respiratory epithelial adenomatoid hamartoma (REAH) is an uncommon lesion of the upper aerodigestive tract first described by Wenig and Heffner in 1995 as prominent glandular proliferations lined by ciliated respiratory epithelium originating from the surface epithelium. The entity is seen most often in male adults. Clinically the lesion presents as a polypoid mass, often in one or both nasal cavities, though other locations have been described. While REAH is benign, awareness and recognition of the lesion is important because it can be easily confused grossly and microscopically with more threatening tumors such as inverted papilloma and sinonasal carcinoma. The literature of REAH is reviewed with detail paid to the histologic diagnosis. The clinical presentation, radiologic findings, and differential diagnosis are also described.

Keywords: Inverted papilloma; Nasopharynx; Respiratory epithelial adenomatoid hamartoma; Sinonasal adenocarcinoma; Upper aerodigestive tract.

Fig. 1

Respiratory epithelial adenomatoid hamartomas are composed of prominent glandular structures of varying sizes

Fig. 2

The glands are lined by ciliated respiratory epithelium. The nuclei are bland. Note the mucinous gland metaplasia

Fig. 3

Inflammatory polyp with edematous inflammatory stroma and single layered glands

Fig. 4

High power of inflammatory polyp showing inflammatory stroma without hyalinization and a single layered gland without the typical features of REAH

Fig. 5

Inverted papilloma originating from overlying squamous epithelium. Note the respiratory epithelial changes that one could confuse with REAH

Fig. 6

Sinonasal adenocarcinoma, low power