Nasal seromucinous hamartoma (microglandular adenosis of the nose): a morphological and molecular study of five cases

Nasal and sinonasal tumors formed by atypical adenomatous lesions arising in respiratory epithelial adenomatoid hamartoma/seromucinous hamartoma

Two benign adenomatous lesions are commonly recognized within the sinonasal tract, namely respiratory epithelial adenomatoid hamartoma (REAH) and seromucinous hamartoma (SH). We present 10 hitherto unrecognized benign polypoid nasal and sinonasal tumoriform lesions having in average 3.6 cm in largest dimension, which are histogenetically related to SH and REAH. In addition to typical structures of REAH and SH, these lesions contained an additional characteristic and slightly atypical adenomatous component, which we termed atypical sinonasal glands arising in SH (ASGSH). ASGSH often produced deep red colored secretion with peripheral clearing similar to that seen in thyroid follicles. In contrast to SH, ASGSH was endowed by both secretory and myoepithelial layers and had mostly angulated shapes with snout-like protrusions into the lumens. Both layers were formed by an irregular, disorganized, and often incomplete cell lining, which had slightly atypical cytological features without mitoses. In 3 cases, ASGSHs revealed sebaceous differentiation, and in 3 cases the stroma produced a well-differentiated cartilage. Neoplastic nature of ASGSH was supported by finding of various mutations as revealed by next generation sequencing in five cases. In two cases each, we found identical mutations in BRAF gene (Val600Glu), and RET gene (Arg912Trp), respectively and in one case FAT1 gene alteration (Pro1665Leu).

Sinonasal seromucinous hamartoma: a single institution case series combined with a narrative review of the literature

PURPOSE

This study aimed to investigate the clinical and histopathological characteristics of sinonasal seromucinous hamartomas (SHs).

METHODS

Eight patients with sinonasal SH and treated at a tertiary hospital between November 2005 and September 2023 were included. Additionally, a systematic review of published articles was conducted, analyzing 48 cases of SH described in the literature.

RESULTS

Among the eight patients treated at our institution, tumors originated from the posterior nasal cavity in four patients and middle turbinate and middle meatus were the primary origin in two patients each. Coexistence of inflammatory nasal polyps (NPs) was observed in four cases. Histopathologically, four patients exhibited focal respiratory epithelial adenomatoid hamartoma (REAH) features, and low-grade dysplasia was found in one patient. A combined analysis with previous literature revealed that 46.3% of all cases originated in the anterior nasal cavity. The proportions of cases accompanied by NPs and those with focal REAH features were 20.5% and 39.1%, respectively. Additionally, the frequencies of cases exhibiting dysplastic features (5.4%) and recurrence (2.1%) were low. Remarkably, tumors originating from the anterior region tended to have a higher frequency of dysplasia than those originating from the posterior region, although this difference was not statistically significant (p = 0.0996).

CONCLUSION

Patients with sinonasal SH showed favorable treatment outcomes following surgical resection. Focal REAH features and accompanying NPs were frequently observed. A substantial proportion of cases originate in the anterior nasal cavity, and these tumors may exhibit a high tendency for dysplasia.

Challenging differential diagnoses in small biopsies from the sinonasal tract

Sinonasal biopsy specimens are a challenging area in anatomic pathology. The small, often fragmented or crushed nature of these biopsies can hinder morphologic assessment. Additionally, many of the tumors in this area are rare and share morphologic, and sometime immunophenotypic similarities. In many cases, immunohistochemistry is helpful if not necessary to reach a specific diagnosis. In other cases, a specific diagnosis is not possible and a differential diagnosis must be given on a biopsy specimen despite access to a well-equipped immunohistochemistry laboratory. This review article groups some of the more challenging entities in the sinonasal region based on morphologic patterns. These include low grade squamoid lesions such as sinonasal (Schneiderian) papilloma and DEK::AFF2 rearranged carcinoma, glandular neoplasms such as intestinal and non-intestinal type sinonasal adenocarcinoma, high-grade carcinomas such as HPV-related multiphenotypic sinonasal carcinoma, NUT carcinoma and SWI/SNF deficient carcinomas, small round blue cell tumors such as teratocarcinosarcoma, neuroendocrine carcinoma and olfactory neuroblastoma, and finally, low grade spindle cell neoplasms such as glomangiopericytoma, biphenotypic sinonasal sarcoma and solitary fibrous tumor.

Seromucinous Hamartoma of the Sinonasal Cavity

Benign tumors or malignant neoplasms must be evaluated in patients with unilateral nasal cavity mass lesions. The 3 most prevalent unilateral benign mass lesions in such individuals are nasal polyps (NPs) and inverted papillomas (IPs). Although rare, it should be kept in mind that sinonasal hamartomas can be occasionally diagnosed as well. Among sinonasal hamartomas, respiratory epithelial adenomatoid hamartoma is more prevalent, with seromucinous hamartoma (SMH) being the second most common. Unlike NPs, sinonasal hamartomas are benign tumors with growth potential, which means it should not be undertreated and warrants surgical removal for treatment. However, sinonasal hamartomas do not have local invasion or malignant transformation potential like IPs; hence, it is vital not to overtreat them. Therefore, understanding the histopathology of SMH and thereby establishing proper surgical planning prior to the surgery remains crucial in such cases. Here, we present a successfully treated case of SMH with a distinctive radiographic, gross, and pathological clinical image of SMH.

Seromucinous Hamartoma of the Lateral Nasal Wall with Infiltration of the Orbit: A Rare Case Report and Review of the Literature

Seromucinous hamartoma is a rare benign glandular proliferation arising from the respiratory epithelium of the sinonasal tract and nasopharynx. It was described for the first time in 1974 by Baillie and Batsakis. Since then, few cases have been reported in the literature with most of them occurring in the posterior nasal septum. We report the case of a 52-year-old woman that presented to our department with left periorbital edema, pain, and dacryorrhea due to seromucinous hamartoma arising from the left inferior turbinate and extending through the lateral nasal wall into the maxilla, the nasolacrimal duct, and the orbit. Endoscopic medial maxillectomy and endoscopic transnasal orbital tumor resection were performed. The patient remains symptom-free for 16 months, till her most recent follow-up. Seromucinous hamartoma of the nasal cavity is an exceedingly rare diagnosis, especially in the lateral nasal wall. It should be included in the differential diagnosis of nasal tumors. According to the literature review, this is the first case report of seromucinous hamartoma with orbit infiltration. Endonasal endoscopic resection is the treatment of choice.

A Rarely Seen Mass of Nasal Cavity: Seromucinous Hamartoma

Seromucinous hamartoma (SH) is a rarely seen benign polypoid mass of the sinonasal tract. Although the most common presentation symptom is nasal obstruction, most of the patients are asymptomatic. In this paper, the authors present an additional case of SH and discuss its differential diagnosis. A 34-year-old male patient presented with progressive nasal obstruction and serous nasal discharge for several months. A well-defined polypoid mass was detected in the left nasal cavity during the endoscopic assessment. Preoperative biopsy was reported as benign polypoid lesion. The mass was resected via transnasal endoscopic approach and final pathological examination was notified as SH.The SH is an uncommon tumor, originates from nasal septum in the most cases and presents as a well-circumscribed polypoid mass. Radiological imaging modalities and biopsy should be performed to distinguish from the sinonasal malignancies. Complete surgical excision is recommended treatment and recurrence is almost never.

Immunohistochemical and genetic analysis of respiratory epithelial adenomatoid hamartomas and seromucinous hamartomas: are they precursor lesions to sinonasal low-grade tubulopapillary adenocarcinomas?

Respiratory epithelial adenomatoid hamartoma (REAH) and seromucinous hamartoma (SH) are rare tumor-like lesions of the nasal cavity, paranasal sinuses, and nasopharynx. The pathogenesis of REAH/SH is still unclear. Neoplastic proliferation, chronic mechanical irritation, inflammation, or possible embryological tissue misplacement are speculated as possible mechanisms of their development. Low-grade tubulopapillary adenocarcinoma (LGTA) is a rare variant of nonsalivary, nonintestinal type sinonasal adenocarcinoma. The aim of this study was to evaluate the immunohistochemical and genetic profiles of 10 cases of REAH/SH, with serous, mucinous, and respiratory components evaluated separately and to compare these findings with the features of 9 cases of LGTA. All cases of REAH/SH and LGTA were analyzed immunohistochemically with a cocktail of mucin antigens (MUC1, MUC2, MUC4, MUC5AC, MUC6) and with epithelial (CK7, CK20, CDX2, SATB2) and myoepithelial markers (S100 protein, p63, SOX10). The next-generation sequencing assay was performed using FusionPlex Solid Tumor Kit (ArcherDx) in 10 cases of REAH/SH, and the EGFR-ZNF267 gene fusion was detected in 1 of them. Two female REAH/SH cases were assessed for the presence of clonality. Using the human androgen receptor assay, 1 case was proved to be clonal. The serous component of REAH/SH was positive for CK7/MUC1 and SOX10 similarly to LGTA. Although REAH/SH and LGTA are histopathologically and clinically separate entities, the overlap in their morphological and immunohistochemical profiles suggests that REAH/SH might be a precursor lesion of LGTA.

Seromucinous hamartoma of inferior turbinate: A case report

RATIONALE

Seromucinous hamartoma is a rare benign glandular proliferation of the sinonasal tract and nasopharynx, and the majority of lesions occur on the posterior nasal septum.

PATIENT CONCERNS

The patient had complaints of rhinorrhea, sneezing, and itching for a number of years, and recurrent right nasal bleeding for which the patient underwent endoscopic removal of a right inferior turbinate tumor. The biopsy result was low-grade, non-intestinal type adenocarcinoma, and the patient was referred to our hospital.

DIAGNOSIS AND INTERVENTIONS

An endoscopic medial maxillectomy of the right nasal cavity was performed. The histopathological analysis of the nasal mass revealed a seromucinous (glandular) hamartoma.

OUTCOMES

The postoperative course was unremarkable. The patient has been followed up regularly for 1 year with no additional treatment and no recurrence.

LESSONS

Seromucinous hamartoma of the nasal cavity is extremely rare, especially in anterior portion of nasal cavity. It is important to distinguish seromucinous hamartoma from adenocarcinoma and to maintain regular long-term follow-up.

Seromucinous Hamartoma of the Nasal Cavity

Seromucinous hamartoma (SMH) is a rare benign epithelial proliferation occurring in the sinonasal tract. The clinical, radiographic, and histologic appearance of SMH may mimic several benign and malignant entities. Presented is a novel case, with a review of the literature focused on potential histologic diagnostic pitfalls.

Sinonasal seromucinous hamartoma

INTRODUCTION

Seromucinous hamartoma (SH) is a rare benign glandular proliferation of the sinonasal tract and nasopharynx. Only few cases have been reported in recent years.

MATERIALS AND METHODS

We performed a retrospective medical record review of seven patients diagnosed with sinonasal SH who underwent endoscopic endonasal surgery.

RESULTS

There were 5 males and 2 females, ranged in age from 40 to 98 years (mean 60 years, SD ± 18.9). Two lesions arise from middle turbinate, two from uncinate process, and 3 (but 4 specimens) from nasal septum. Pathological features revealed a polypoid lesion with submucosal proliferation of seromucinous glands arranged in lobular and haphazard patterns. In immunohistochemical study, the seromucinous glands of SH were reactive for cytokeratin, including CK7, CK19, HMWK, but negative for CK20.

CONCLUSION

Sinonasal SH is a rare diagnosis characterized by a polypoid lesion with a haphazard proliferation of seromucinous glands. The rhinologists should consider it in the differential diagnosis of a polypoid lesion in the nasal cavity.

Olfactory Epithelial Hamartoma: A New Subtype of Sinonasal Hamartoma

Sinonasal epithelial hamartomas occurring in adults are classified as seromucinous hamartoma (SMH) or respiratory epithelial adenomatoid hamartoma (REAH). We describe herein a novel subtype of adult sinonasal hamartoma that contains olfactory epithelium, a histologic feature not previously reported in the literature. Our pathology department database was retrospectively searched for sinonasal hamartomas containing areas of olfactory epithelium. Six relevant cases (3 male and 3 female patients; age, 30 to 77 y) were retrieved, and available pathology slides and clinical and imaging data from patient charts were reviewed. Five of the lesions were unilateral solitary, polypoid, pedunculated masses, 38 to 80 mm in length, lodged in the nasal olfactory cleft. The sixth lesion was associated with bilateral nasal polyposis, and its precise localization was not known. All patients were treated by transnasal endoscopic surgery. None of the 3 patients who had received adequate follow-up evaluation exhibited recurrence. Histologically, all lesions resembled SMH or REAH, with areas of olfactory epithelium comprising olfactory receptors and sustentacular and basal cells. Olfactory epithelium was observed at the lesion surface or in invaginated gland-like structures, and it contained focal aggregates of filamentous cell processes. Some olfactory receptor cells or cell processes were also present in the seromucinous gland component of lesions. Olfactory receptor cells expressed CD56 (neural cell adhesion molecule), and the filamentous aggregates contained CD56, neurofilaments, and synaptophysin. Aside from SMH and REAH, we have described a third subtype of adult sinonasal hamartoma-olfactory epithelial hamartoma-which shares the benign character of the other 2.

Update from the 4th Edition of the World Health Organization Classification of Head and Neck Tumours: Tumors of the Nasal Cavity, Paranasal Sinuses and Skull Base

The sinonasal tract remains an epicenter of a diverse array of neoplasia. This paper discusses changes to the WHO classification system of tumors involving this area. In particular, seromucinous hamartoma, NUT carcinoma, biphenotypic sinonasal sarcoma, HPV-related carcinoma with adenoid cystic features, SMARCB1-deficient carcinoma, and renal cell-like adenocarcinoma are discussed.

Low-Grade Epithelial Proliferations of the Sinonasal Tract

Low-grade epithelial proliferations of the sinonasal tract include Schneiderian papillomas, respiratory epithelial adenomatoid hamartoma, seromucinous hamartoma and low-grade non-intestinal adenocarcinoma. There is considerable overlap in their clinical presentation, endoscopic appearance, and imaging features. Although well-described diagnostic criteria exist, a definitive diagnosis may be difficult to reach on a small biopsy. Schneiderian papillomas are divided into fungiform, inverted, and oncocytic types, each with characteristic clinical and morphological features. The latter two may progress to malignancy. The majority are still considered to be HPV-related. Two lesions are designated as hamartomas, but their pathogenesis remains uncertain, with inflammatory and neoplastic origins proposed. Respiratory epithelial adenomatoid hamartoma is increasingly being recognized for its association with chronic rhinosinusitis and olfactory cleft site of origin. Seromucinous hamartoma has gained attention in recent years and overlaps with both respiratory epithelial adenomatoid hamartoma and low-grade non-intestinal adenocarcinoma. Controversy surrounds their distinction, particularly from low-grade adenocarcinoma. The latter generally is cured by complete excision, with a 26 % risk of recurrence but rare metastases and deaths from disease.

Respiratory epithelial adenomatoid hamartoma of the nose: an updated review

BACKGROUND

This study was designed to update clinical and imaging features as well as treatment outcomes of the nasal respiratory epithelial adenomatoid hamartoma (REAH). Data sources included case reports, original articles, and reviews published in English or French in PubMed from 1995 to date.

METHODS

Only published articles that met Wenig's histological criteria for the diagnosis of REAH were included.

RESULTS

REAH is not rare and is probably underdiagnosed. It is usually observed in the fifth decade of life with a 3:2 male/female predilection. REAH can be represented in two forms: as an isolated lesion (less frequent) or in association with an inflammatory process (especially nasal polyposis). It was observed in 35-48% of patients undergoing endoscopic endonasal surgery for nasal polyposis. Its origin is found, in most cases, in the olfactory cleft, which is exhibited on computed tomography (CT) scans by widened opacified olfactory clefts without bone erosion. Resection of REAH from the olfactory clefts does not worsen, but instead, can improve the sense of smell after surgery.

CONCLUSION

Looking for REAH on CT scans and during endoscopic examination can lead to its diagnosis and help avoid aggressive surgical procedures and their complications. Endoscopic resection is the treatment of choice. The removal of REAH constitutes a specific surgery on the olfactory clefts, which can improve nasal obstruction as well as sense of smell. Whether REAH can be defined as a hamartoma, an inflammatory reactive process, or a neoplastic lesion remains to be determined.

Seromucinous hamartoma in the nasal cavity medial to the middle turbinate: report of 2 cases and review of the literature

BACKGROUND

Seromucinous hamartoma, a type of epithelial hamartoma, is a rare benign glandular proliferation of the sinonasal tract and nasopharynx. Herein, we present 2 rare cases of seromucinous hamartoma arising in the nasal cavity medial to the middle turbinate.

METHODS AND RESULTS

This is a case report of 2 patients diagnosed with seromucinous hamartoma of the nasal cavity and a review of the literature.

CONCLUSION

Seromucinous hamartoma of the nasal cavity is an exceedingly rare diagnosis but should be included in the differential diagnosis of a posterior nasal tumor. Most cases arise from the posterior nasal cavity medial to the middle turbinate rather than lateral to the middle turbinate.

Recently described sinonasal tract lesions/neoplasms: considerations for the new world health organization book

Since the publication of the World Health Organization Classification of Head and Neck Tumors (Barnes et al., World Health Organization classification of tumours. Pathology and genetics head and neck tumours, IARC Press, Lyon, pp 10-80, 2001), a number of sinonasal lesions have been more completely described. This manuscript will focus on three such "new" lesions including sero mucinous hamartoma, HPV-related carcinoma with adenoid cystic-like features and low-grade sinonasal sarcoma with neural and myogenic features.

A unique case of sclerosing polycystic adenosis of the sinonasal tract

Sclerosing polycystic adenosis is an extremely uncommon, recently described, sclerosing lesion of the salivary glands that appears histologically similar to fibrocystic changes of the breast. The key histopathologic features of sclerosing polycystic adenosis include lobular proliferation of ductal and acinar elements, cystically dilated ducts exhibiting frequent apocrine and sebaceous metaplasia, eosinophilic intracytoplasmic granules within some acinar-type cells, intraductal epithelial hyperplasia, and dense fibrosis. Most described cases have occurred in the major salivary glands, particularly the parotid gland. Although most authorities consider sclerosing polycystic adenosis to be a pseudoneoplastic process, the occurrence of dysplasia and carcinoma in situ of ductal epithelium reported recurrence rates of up to 30%, and recent evidence of clonality suggests a possible neoplastic etiology. However, there have been no cases of metastasis. Herein, we report the first case of sclerosing polycystic adenosis of the sinonasal tract in a 79-year-old woman presenting with a sinonasal mass.

Primer effect in the detection of mitochondrial DNA point heteroplasmy by automated sequencing

The correct detection of mitochondrial DNA (mtDNA) heteroplasmy by automated sequencing presents methodological constraints. The main goals of this study are to investigate the effect of sense and distance of primers in heteroplasmy detection and to test if there are differences in the accurate determination of heteroplasmy involving transitions or transversions. A gradient of the heteroplasmy levels was generated for mtDNA positions 9477 (transition G/A) and 15,452 (transversion C/A). Amplification and subsequent sequencing with forward and reverse primers, situated at 550 and 150 bp from the heteroplasmic positions, were performed. Our data provide evidence that there is a significant difference between the use of forward and reverse primers. The forward primer is the primer that seems to give a better approximation to the real proportion of the variants. No significant differences were found concerning the distance at which the sequencing primers were placed neither between the analysis of transitions and transversions. The data collected in this study are a starting point that allows to glimpse the importance of the sequencing primers in the accurate detection of point heteroplasmy, providing additional insight into the overall automated sequencing strategy.

Sinonasal seromucinous hamartoma: a review of the literature and a case report with focal myoepithelial cells

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.

Seromucinous hamartoma of the nasal cavity: a report of two cases and review of the literature

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.