Low Grade Glandular Lesions of the Sinonasal Tract: A Focused Review

Abstract

The sinonasal tract is a complex anatomic site with an exhaustive list of possible diagnoses. While most biopsies or resections encountered routinely consist of common diagnoses such as inflammatory polyps and papillomas, occasional cases are more difficult, and separating reactive or benign from malignancy can be challenging. One of the most poorly understood and daunting categories is low grade glandular or tubular proliferations, particularly on small biopsies. Possible diagnoses such as reactive lesions, respiratory epithelial adenomatoid hamartoma (REAH), seromucinous (glandular) hamartoma (SH) and low grade sinonasal adenocarcinomas (LGSNAC) must be entertained. REAH is composed of respiratory epithelial lined submucosal glands with variable connection to the surface and periglandular hyalinization. SH is a tubular proliferation reminiscent of normal serous glands which may be associated with REAH.LGSNAC is a diverse group of bland tubular and/or papillary tumors, which have a recurrence potential but an as yet uncertain potential for metastasis or mortality. The management for these lesions can be vastly different and conservative management is preferable, making this distinction more than academic. However, complicating this category are controversies surrounding their nature as reactive lesions versus neoplasms, the histologic and immunohistochemical overlap, and possible precursor relationships between some of them.

Sinonasal Seromucinous Hamartoma: A Review of the Literature and a Case Report with Focal Myoepithelial Cells

“…Weinreb [19], in a recent review of low grade glandular lesions of the sinonasal tract, comments that the typical features of both REAH and seromucinous hamartoma can focally be seen within inflammatory lesions as well as within normal sinonasal mucosa. He also observed that these foci can have inconsistent myoepithelial staining.…”

Seromucinous Hamartoma of the Nasal Cavity: A Report of Two Cases and Review of the Literature

“…The epithelium is bland and mature, although uncommonly one can see attenuated epithelium that appears collapsed (atrophic). Focal hyperplasia of the adjacent seromucinous glands [19], a typical finding of SH, may also be present. This is a common overlapping feature between REAH and SH, in addition to their common origins in the posterior nasal cavity and septum.…”

“…Many cases of SH show localized REAH like changes with glands and cysts lined by invaginated respiratory epithelium, although this is usually only focal [15]. Similarly, many cases of REAH show seromucinous glands [19]. As such, they may simply represent a continuum of changes that have been somewhat arbitrarily divided.…”

“…As such, they may simply represent a continuum of changes that have been somewhat arbitrarily divided. The term chondro-osseous REAH has been used to describe examples of REAH distinguished by the presence of either cartilage or bone [19,20]. These may represent a hybrid lesion comprised of both REAH and chondromesenchymal hamartoma together.…”

“…Inflammatory nasal polyposis often precedes or coexists with REAH. However, these inflammatory polyps are thought to be reactive rather than associated lesions [19]. Immunohistochemistry is not usually necessary to make the diagnosis but the respiratory epithelium of REAH is positive for cytokeratin 7 and negative for cytokeratin 20, CDX2, S100 and p63, while the basal layer of the gland-like structures is positive for 34betaE12 [20].…”