PhiliPPine Journal of otolaryngology-head and neck Surgery Vol. 33 no. 2 July – december 2018 PhiliPPine Journal of otolaryngology-head and neck Surgery 6362 PhiliPPine Journal of otolaryngology-head and neck Surgery PhiliPPine Journal of otolaryngology-head and neck Surgery 6362 PhiliPPine Journal of otolaryngology-head and neck Surgery UNDER THE MICROSCOPE Philipp J Otolaryngol Head Neck Surg 2018; 33 (2): 62-63 c Philippine Society of Otolaryngology – Head and Neck Surgery, Inc. Respiratory Epithelial Adenomatoid HamartomaJose M. Carnate Jr., MDAgustina D. Abelardo, MD Department of Pathology College of Medicine University of the Philippines Manila Correspondence: Dr. Jose M. Carnate, Jr. Department of Pathology College of Medicine, University of the Philippines Manila 547 Pedro Gil St. Ermita, Manila 1000 Philippines Phone (632) 526-4450 Telefax (632) 400-3638 Email: jmcjpath@gmail.com The authors declared that this represents original material that is not being considered for publication or has not been published or accepted for publication elsewhere, in full or in part, in print or electronic media; that the manuscript has been read and approved by the authors, that the requirements for authorship have been met by the authors, and that the authors believe that the manuscript represents honest work. Disclosures: The authors signed a disclosure that there are no financial or other (including personal) relationships, intellectual passion, political or religious beliefs, and institutional affiliations that might lead to a conflict of interest. A 65-year-old man consulted with a history of chronic snorting with a sensation of obstruction on the left side of the nasopharynx particularly when in supine position. A few days prior to consult, the patient had blood-tinged nasal discharge, thus this admission. No other symptoms were reported. Nasal endoscopy showed a sessile exophytic lesion with a vaguely nodular surface seen as a polypoid nasopharyngeal mass on Computed Tomography scan. (Figure 1) Excision of the mass was performed. Received in the surgical pathology laboratory was a 1.8 x 1.5 x 0.6 cm red to brown, rubbery to firm, vaguely ovoid mass with a nodular external surface. Cut section showed a light gray solid surface. Microscopic examination shows a broad-based exophytic mass with invaginations of the surface epithelium and proliferated glands within the stroma. (Figure 2) The glands are tubular or variably dilated - many are lined by a respiratory-type epithelium with goblet cells and a thickened basement membrane while the tubular glands are lined by a monolayered cuboidal epithelium. (Figure 3) Based on these features, we signed the case out as a respiratory epithelial adenomatoid hamartoma (REAH). REAH is a benign proliferation of sinonasal tract glands derived from the surface epithelium.1 It occurs primarily in male adults with a median age in the sixth decade of life. Most cases arise in the posterior nasal septum while less common sites of involvement include other parts of the nasal cavity, the nasopharynx, and paranasal sinuses.2 Common symptoms include nasal obstruction, stuffiness and epistaxis.1,3,4 REAH presents as a polypoid lesion and may measure up to 6 cm in widest diameter.1 Microscopically, there is a proliferation of small to medium-sized glands dispersed in abundant stroma. Invagination of the glands from the surface epithelium may be seen.3 The glands are Creative Commons (CC BY-NC-ND 4.0) Attribution - NonCommercial - NoDerivatives 4.0 International Figure 1. Vaguely nodular sessile nasopharyngeal mass on paranasal endoscopy (dotted area). Inset shows the mass on CT scan (arrow). PhiliPPine Journal of otolaryngology-head and neck Surgery 6362 PhiliPPine Journal of otolaryngology-head and neck Surgery PhiliPPine Journal of otolaryngology-head and neck Surgery Vol. 33 no. 2 July – december 2018 PhiliPPine Journal of otolaryngology-head and neck Surgery 6362 PhiliPPine Journal of otolaryngology-head and neck Surgery UNDER THE MICROSCOPE Figure 2. Sessile exophytic mass with invaginations of the surface epithelium and proliferated glands within the stroma. (Hematoxylin-Eosin, 40X magnification). Figure 3. Proliferated glands and stroma. (Hematoxylin-Eosin, 100X Magnification). High power (400X magnification) shows glands lined by respiratory-type epithelium with goblet cells (Inset A, arrow), monolayered cuboidal epithelium (Inset B, double arrow), and thickened basement membrane (Inset B, asterisk). REFERENCES 1. Weng BM, Franchise A, Ro JY. Respiratory epithelial adenomatoid hamartoma. In: El-Naggar AK, Chan JKC, Grandis JR, Takata T, Slootweg PJ. WHO Classification of Head and Neck Tumors. IARC: Lyon 2017. p.31. 2. Zulkepli SZ, Husain S, Gendeh BS. Respiratory epithelial adenomatoid hamartoma of the nasal septum. Philipp J Otolaryngol Head Neck Surg. 2012 Jan-Jun;27(1):28-30. 3. Ramadhin AK. Respiratory epithelial adenomatoid hamartoma: a rare cause of nasal obstruction – case report. Glob J Oto. 2017 May; 7(5):1-3. DOI:10.19080/GJO.2017.07.555723. 4. Saniasiaya J, Shukri NM, Ramli RR, Abdul Wahab WNNW, Zawawi N. Sinonasal respiratory epithelial adenomatoid hamartoma: an overlooked entity. Egyptian Journal of Ear, Nose, Throat and Allied Sciences. 2017 Jul;18(2):191-193. https://doi.org/10.1016/j.ejenta.2016.12.014. round to oval, lined by respiratory-type epithelium with admixed goblet cells. Thickened basement membranes surround some of the glands, and smaller seromucinous glands lined by cuboidal epithelium may also be admixed among the latter. Other alterations may include squamous, chondroid and osseous metaplasia.1,4 Rarely, REAH may occur synchronously with inverting sinonasal papillomas or inflammatory polyps.1 It may be mistaken for these two entities along with sinonasal low-grade adenocarcinomas. Careful attention to the typical morphology including absence of an infiltrative growth pattern and atypia allow distinction from these entities particularly the malignant mimics.3 A related entity is a seromucinous hamartoma with which REAH is believed to form a morphological spectrum.1 REAH is benign and complete excision confers cure.1 Malignant transformation has not been reported.1,3,4 (Hematoxylin – Eosin , 40X) (Hematoxylin – Eosin , 100X) (Hematoxylin – Eosin , 400X)