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

Abstract

The sinonasal tract is a complex anatomic site, home to a wide variety of reactive, inflammatory, benign, and malignant lesions. Inflammatory polyps and papillomas are usually easily recognized by pathologists. A poorly understood lesion that has been more clearly defined in recent years is the nasal hamartoma. The epithelial subtypes include seromucinous hamartoma, respiratory epithelial adenomatoid hamartoma, and hybrid lesions. Seromucinous hamartomas have only been recognized and substantially reported over the past few years. They are a diagnostic challenge, needing to be distinguished from low grade adenocarcinomas, and are of interest because most of the basic questions about their pathophysiology remain unanswered. Herein, we present two novel cases of seromucinous hamartoma with features that partly expand the morphologic spectrum of these lesions, discuss the differential diagnosis, and review the literature to compare our findings with previously reported cases with the aim of better understanding this interesting entity.

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

“…They are both associated with inflammation. In addition, foci of seromucinous hamartoma are frequently found in REAH, and vice versa [5,6,8,9]. Our case also demonstrates focal REAH-like features, and supports the suggestion that REAH and seromucinous hamartoma are related lesions.…”

“…The entity was initially described by Baillie and Batsakis in 1974 [1] as a single case report. Since then, 20 additional cases have been reported in the English literature [2][3][4][5][6][7][8] (Table 1). The male to female ratio is approximately 1:1.…”

Low-Grade Epithelial Proliferations of the Sinonasal Tract

“…SMH was first described in 1974 as a single case report of a nasopharyngeal ''glandular (seromucinous) hamartoma'' [18]. There were scattered case reports in the intervening years, but SMH has been resurrected in earnest over the last 6 years, primarily because of its relationship to REAH and unique immunoprofile [19][20][21][22].…”

Recently Described Sinonasal Tract Lesions/Neoplasms: Considerations for the New World Health Organization Book

“…Subsequent to that description, there have been a number of other case reports but only recently was SH the subject of larger studies, including 7 cases reported by Weinreb et al [3] and 5 cases reported by Ambrosini-Spaltro et al [4]. To date, there are less than 25 cases of SH identified in the world literature [2][3][4][5][6][7][8][9][10]. Table 2 details the comparison of various features among sinonasal hamartomas.…”

“…The surface respiratory epithelium shows p63 positive basal cells but the seromucinous glands are typically negative for p63 [2,4,5,10]. In addition, calponin and muscle specific actin are negative in both the surface respiratory epithelium and the seromucinous glands.…”