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

Abstract

Seromucinous hamartoma is a benign lesion of the sinonasal tract. Since its description in 1974, only a small number of additional cases have been reported. It is composed of a proliferation of seromucinous glands and ducts within a variable fibrous stroma. The serous component typically stains positively for S100 (at least focally) and lacks p63 positive abluminal cells. The lack of myoepithelial/basal cells is an important diagnostic feature of seromucinous hamartoma; their absence could lead to an incorrect diagnosis of low-grade sinonasal adenocarcinoma. We report the case of a polypoid mass resected from the posterior nasal cavity and nasopharynx of a 54-year-old woman. The lesion contained a population of small and large glands lined by cuboidal to flattened cells within a hypocellular stroma varying from dense and sclerotic to myxoid. Additionally, there was a superficial focus of ciliated invaginated surface epithelium and glands. Throughout the lesion there were no cytologic or architectural features of malignancy. The histologic features were diagnostic of seromucinous hamartoma. Immunohistochemistry showed focal S100 positivity of the serous glands. However, in contrast to previously reported cases, the glands focally showed an outer basal layer that was calponin, p63 and actin positive. Our case demonstrates two important points. First, complete absence of p63 staining should not necessarily be a required feature in the diagnosis of seromucinous hamartoma. Second, the ciliated larger glands-in keeping with respiratory epithelial adenomatoid hamartoma (REAH)-support the suggestion that seromucinous hamartoma and REAH are a spectrum of lesions, often seen together.

A Subset of Sinonasal Non-Intestinal Type Adenocarcinomas are Truly Seromucinous Adenocarcinomas: A Morphologic and Immunophenotypic Assessment and Description of a Novel Pitfall

“…Regarding SSH, while the ductoacinar cells are uniformly negative we did identify one case with a focal delimiting myoepithelial cell layer. Thus in keeping with a recent report that not all SSH are devoid of myoepithelial cells [32].…”

Low-Grade Epithelial Proliferations of the Sinonasal Tract

“…9a, b). Immunohistochemistry shows CK7, CK19 and S100 positivity with a total (or near total) absence of basal cells, confirmed by the absence of periglandular p63 staining [19] (Fig. 9c, d).…”

“…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.…”

“…In addition, calponin and muscle specific actin are negative in both the surface respiratory epithelium and the seromucinous glands. Fleming et al [8] reported a case of SH showing p63, calponin and actin staining indicating that not all SHs lack p63 reactivity. S100 protein staining is limited to the seromucinous glands.…”