Sinonasal Hamartomas: From Nasal Chondromesenchymal Hamartoma to Respiratory Epithelial Adenomatoid Hamartoma. Report of six Cases and Review of the Literature

Abstract

Sinonasal hamartomas are uncommon lesions of nasal and sinus cavities. Based on indigenous cellular components and characteristic histologic features, they are further classified into four entities: respiratory epithelial adenomatoid hamartoma (REAH), seromucinous hamartoma (SH), chondro-osseous and respiratory epithelial hamartoma (CORE), and nasal chondromesenchymal hamartoma (NCH). REAH, SH, and CORE are seen in adult patients, while NCH predominantly occurs in newborns and infants. Morphologically REAH and SH are composed of respiratory epithelium and seromucinous glands, CORE is related to REAH but with additional feature of chondroid and/or osseous tissue, and NCH is composed of chondroid and stromal elements but devoid of epithelial component. All four lesions can present as sinonasal mass lesions and with associated obstructive symptoms. Given the rarity of these lesions, diagnosis can be challenging, especially in unusual clinical scenario. In this study, we report six cases of sinonasal hamartoma, including one case of NCH, one case of CORE, two cases of SH, and two cases of REAH. All cases were from adult patients including four men and two women. We also review the literature of the clinical and pathologic features of these rare lesions.

International Consensus Statement on Allergy and Rhinology: Sinonasal Tumors

“…Hamartomas are benign malformations consisting of multiple tissue types. In the sinonasal cavity, hamartomas can be further classified into four histopathologic entities: respiratory epithelial adenomatoid hamartoma (REAH), chondro‐osseous respiratory epithelial adenomatoid hamartoma (COREAH), nasal chondromesenchymal hamartoma (NCH), and seromucinous hamartoma 571 …”

“…Grossly, REAH typically appears as a polypoid mass, usually darker and more indurated than an inflammatory polyp 571 . Histologically, REAH classically demonstrates glandular proliferation and a thickened hyalinized basement membrane, often within a background of inflamed stroma 585 .…”

“…On histology, NCH demonstrates predominantly cartilaginous nodules, ranging in differentiation from immature chondromyxoid matrix to mature cartilage. An osseous component may also be present, ranging in differentiation from immature woven bone to mature ossicles 571 . Generally, no significant mitotic activity or necrosis is expected.…”

Are Focal Complex Proliferations in Respiratory Epithelial Adenomatoid/Seromucinous Hamartomas Clues of Precursor Neoplastic Lesions to Sinonasal Low-Grade Tubulopapillary Adenocarcinoma?

“…The assumptions that respiratory epithelial adenomatoid hamartoma and seromucinous hamartoma are a spectrum of the same entity and that they are potential precursor lesions to sinonasal nonsalivary nonintestinal-type low-grade tubulopapillary adenocarcinoma have been raised by Li et al and others. 1–6 We describe three nasal septum sinonasal hamartomas with overlapping features between respiratory epithelial adenomatoid hamartoma and seromucinous hamartoma emphasizing their continuity. We postulate whether the presence of focal complex architectural glandular proliferations in these hybrid lesions might link them as precursor neoplastic lesions to low-grade tubulopapillary adenocarcinoma.…”

“…al. 1 which has been recently published in the “ International Journal of Surgical Pathology ”. The assumptions that respiratory epithelial adenomatoid hamartoma and seromucinous hamartoma are a spectrum of the same entity and that they are potential precursor lesions to sinonasal nonsalivary nonintestinal-type low-grade tubulopapillary adenocarcinoma have been raised by Li et al and others.…”