Sialadenoma Papilliferum: Analysis of Seven New Cases and Review of the Literature

Sialadenoma papilliferum-like intraductal papillary tumor with unveiling BRAF V600E and PIK3CA H1047R mutations: Case report with molecular analysis and literature review

INTRODUCTION

Sialadenoma papilliferum (SP), a rare minor salivary gland tumor, shares morphological and genetic similarities with syringocystadenoma papilliferum. Recent studies have identified BRAF V600E or HRAS mutations in SP, suggesting its neoplastic nature. Despite being uncommon, SP poses diagnostic challenges due to its resemblance to other lesions like squamous papilloma. The emergence of sialadenoma papilliferum-like intraductal papillary tumor (SP-IPT) further complicates its classification, emphasizing the need for thorough investigation.

CASE PRESENTATION

A 50-year-old male presented with a left palatal lesion histologically diagnosed as SP-IPT. Surgical resection revealed characteristic features, including papillary projections into cystically dilated ductal spaces. Immunohistochemistry confirmed positivity for pan-keratin AE1/AE3, cytokeratin 7, SOX10, and BRAF V600E. Whole-exome sequencing identified BRAF V600E and PIK3CA H1047R mutations. No recurrence was observed three months post-excision.

DISCUSSION

SP-IPT's diagnostic complexity stems from its resemblance to SP without an exophytic papillary component. However, shared BRAF mutations suggest a close relationship between the two entities. Similarities with skin adnexal tumors underscore the importance of molecular markers in tumor classification. The identification of PIK3CA mutation in SP-IPT adds to its molecular diversity, warranting further investigation into its clinical significance.

CONCLUSION

This study presents a case of SP-IPT with unique histological and molecular features, highlighting its diagnostic and therapeutic challenges. The co-occurrence of BRAF V600E and PIK3CA H1047R mutations suggests a distinct molecular profile in SP-IPT, necessitating further research to elucidate its biological behavior and clinical implications.

Sialadenoma papilliferum-like intraductal papillary tumour: an emerging entity with intercalated duct differentiation showing MAPK pathway activation in both ductal and myoepithelial cells

Sialadenoma papilliferum-like intraductal papillary tumour (SP-IPT) is a recently described salivary gland tumour that shows identical morphology to sialadenoma papilliferum (SP) except for the lack of an exophytic papillary component. However, the immunohistochemical phenotypes and molecular profiles of SP-IPT remain unclear. This study aims to report new cases of SP-IPT and to determine its cellular differentiation and molecular basis. After histopathological review, four cases of SP-IPT were retrieved. Immunohistochemical staining was performed to analyse the expression patterns of cytokeratin 7 (CK7), p63, smooth muscle actin (SMA), vimentin, S100, mammaglobin, androgen receptor, SOX10, BRAF V600E-mutated protein, and phosphorylated ERK. Sanger sequencing was performed to determine the mutation status of the BRAF, KRAS, NRAS, and HRAS genes. All four cases affected the posterior mandible with a mean age of 62 years and a male-to-female ratio of 3:1. Histologically, all cases consisted of multiple tubular and cystic structures with varying sizes and shapes. The tubulocystic components were lined by a double or few-layered epithelium frequently showing a micropapillary pattern. The outer layer consisted of a rim of myoepithelial cells, which were CK7+/p63+/SMA+/vimentin+/S100+/SOX10+. The inner ductal cells were CK7+/S100+/SOX10+, consistent with intercalated duct differentiation. All cases harboured BRAF V600E mutations, but no other mutations were detected. The BRAF V600E-mutated protein and phosphorylated ERK were expressed in both ductal and myoepithelial cells. These findings demonstrate the immunohistochemical and molecular similarities between SP-IPT and SP and the role and extent of MAPK pathway activation in the pathogenesis of SP-IPT.

Clinicopathologic Study of Sialadenoma Papilliferum of the Minor Salivary Glands: A Series of 8 New Cases With BRAF V600E Mutation-specific Immunohistochemical Analysis

Introduction. Sialadenoma papilliferum (SP) is a rare benign neoplasm that usually arises in the minor salivary glands. Recently, it was demonstrated that SP shares similar molecular genetic alterations (BRAF V600E or HRAS mutations) with its morphologic analog, syringocystadenoma papilliferum. Methods. We sought to perform clinicopathologic and immunophenotypic (BRAF V600E and SOX10) analyses on 8 new cases of SP. Results. The cases were from 4 males and 4 females, with ages ranging from 28 to 81 years (average: 64 years). The common locations were the hard palate (n = 3) and buccal mucosa (n = 3). Histopathologically, 7 cases were classic and 1 case was oncocytic. BRAF V600E immunohistochemistry (IHC) was positive in all classic SP, involving both the exophytic and endophytic components, but negative in the oncocytic SP. SOX10 was positive in the endophytic ductal cells of the evaluated classic SP but was negative in the oncocytic SP. Conclusions. We report 8 new cases of this rare salivary gland neoplasm, using BRAF V600E and SOX10 IHC to further support the following points: (1) the functional role of BRAF V600E mutation, RAS/mitogen-activated protein kinase signaling pathway in the pathogenesis of classic SP of salivary glands by IHC; (2) the analogous relationship between SP, syringocystadenoma papilliferum, and papillary seromucinous adenocarcinoma with sinonasal papilloma-like surface component (PSASP-like surface); (3) endophytic ductal component in classic SP arises from the intercalated ducts and not the excretory ducts; and (4) oncocytic SP is distinct from classic SP.

Uncommon case of cytopathological features of sialadenoma papilliferum

Sialadenoma papilliferum, a benign and rare salivary gland neoplasm, accounts for 0.4%-1.2% of all salivary gland tumors and occurs primarily in minor salivary glands of the oral cavity. Here, we report a case of sialadenoma papilliferum and its associated cytological findings. A papillary tumor was incidentally detected on the palate of an 86-year-old Japanese man. Conventional oral exfoliative cytology was performed; the cytology smear exhibited epithelial clusters composed of atypical epithelial cells with a high nuclear/cytoplasm ratio and arranged in sheet or small papillary-like projections. Cytoplasmic vacuoles were also observed in the papillae. It was difficult to make a definitive diagnosis due to the presence of uncommon cytological features. The excisional biopsy specimen revealed histological features characteristic of sialadenoma papilliferum. Mutational analysis detected BRAFV600E mutation, which confirmed the diagnosis of sialadenoma papilliferum. To the best of our knowledge, no prior cytomorphological evaluations of sialadenoma papilliferum have been reported in detail. Oral exfoliative cytology specimens from salivary gland tumors can demonstrate uncommon cytomorphological features. A differential diagnosis of sialadenoma papilliferum can be based on the observation of mildly atypical epithelial cells that form small papillary-like structures.

Spectrum of salivary gland diseases: A 24-year single-institution retrospective study

Introduction

Salivary glands are exocrine glands and are classified as major and minor salivary glands. Salivary gland pathologies are classified as neoplastic and non-neoplastic. The neoplasms of salivary glands can be benign or malignant.

Aim

The aim of the study was to describe the frequency of various salivary gland diseases reported in our institution from 1997 to 2021.

Methodology

This was a 24-year retrospective study of salivary gland lesions processed and reported by the Department of Oral Pathology and Microbiology. Data regarding age, gender, site, and diagnosis were obtained and studied.

Results

Amongst the total 5928 biopsied cases reported, 6% were salivary gland pathologies. Two hundred sixty-six were non-neoplastic lesions and 81 were neoplastic. The most common non-neoplastic lesion was mucous extravasation cyst. The most common neoplastic lesion was pleomorphic adenoma.

Conclusion

The frequency of occurrence of salivary gland lesions in the last 24 years of this institution is almost similar to that stated in other published studies.

Surgery for Cystadenoma of the Retromolar Pad Area With Reconstruction Using a Buccal Fat Pad Flap: A Case Report

Salivary gland tumors can also occur rarely in the retromolar area, though common near the junction of hard and soft palate, labial mucosa, and buccal mucosa. Most salivary gland tumors in the retromolar pad area are malignant and should be excised. The cystadenoma is a rare, benign, salivary gland tumor. Importantly, incomplete resection of this tumor can lead to recurrence or cervical lymph node metastasis. We reported herein a case of cystadenoma arising in the right retromolar pad area in a 63-year-old male patient who underwent reconstruction using a buccal fat pad flap (BFPF) after the surgical removal of the tumor with a 10-mm margin left a defect with bone exposure. No evidence of recurrence or complication was found at the postoperative, three-year follow-up.

Case Report: Papillary Lesions at the Mouth Floor May Mimic Sialadenoma Papilliferum

Salivary gland tumor Sialadenoma papilliferum (SialP) clinically resembles papillary epithelial lesions, such as squamous papilloma (SqP) or verrucous leukoplakia. Pathological sampling including an adequate depth of both the mucosa and submucosa layer is required for discrimination between the diseases. Though ductal proliferation in the submucosa is characteristic in SialP, papillary lesions arising at the mouth floor, specifically near the ductal orifice, are more problematic. Salivary gland ductal ectasia, along with the overlying papillary hyperplasia, may mimic the biphasic tumorous growth pattern of SialP, making discrimination extremely difficult. Further cellular dysplasia in the papillary mucosal lesion raises the possibility of malignant transformation in a known benign lesion, SialP. Herein, we present a case of SqP at the mouth floor which mimicked both clinical and pathological features of SialP and compared it with a definite case of SialP. Moreover, we discuss major differential points that clinicians and pathologists should consider during diagnosis of oral papillary lesions arising near the salivary glands.

Oncocytic variant of sialadenoma papilliferum - a rare salivary gland tumor: A case report

Background

Sialadenoma papilliferum (SP) is a rare minor salivary gland neoplasm that accounts for less than 1% of all salivary gland tumors. The tumor typically affects older people, presenting most commonly as a slow-growing tumor of the hard palate, although other anatomical subsites, comprising the oral cavity and parotid glands, have also been reported.

Case Report

We report a SP occurring in a 90-year-old female. The patient described feeling a nodule on her palate for several years. The lesion was painless and clinically resembled a round craterlike ulceration of diameter 3 mm. The excisional biopsy was diagnosed histologically as SP. Here, we report the clinicopathological and radiological findings of palatal SP.

Conclusions

SP is a rare, benign salivary gland neoplasm, and there are only a few cases described in the literature. Although mostly benign, malignant transformation can occur and should prompt the clinician to ensure complete removal of the tumor tissue.

Key words:Sialadenoma papilliferum, minor salivary gland tumor, histopathology, oral pathology, case report.

Sialadenoma papilliferum of a minor salivary gland with transformation to mucoepidermoid carcinoma

Sialadenoma papilliferum (SP) is a rare benign tumor usually occurring in the minor salivary glands. Only two cases of malignant transformation of SP and an occasional case of dysplasia in SP have been reported in the literature till now. We report a case of SP of a minor salivary gland in a middle-aged male where the exophytic component retained the histomorphological features of SP while the endophytic component displayed characteristics of a mucoepidermoid carcinoma. Malignant change in sialadenoma papilliferum is an extremely rare phenomenon that requires further research and documentation. Careful evaluation of morphologic features and reporting of more such cases is required to delineate the clinical behavior of this unusual tumor.

Activating HRAS mutation in a case of inverted ductal papilloma of the salivary gland

Inverted ductal papilloma (IDP) is one of the least common benign papillary/cystic neoplasms of the salivary duct system, being characterized histologically by florid hyperplasia of duct-type epithelial cells into a cystic lumen near the orifice with occasional endophytic growth of the surface squamous epithelium along the terminus of the affected excretory duct. Given its rarity, the exact etiology of IDP remains to be defined. We herein present the first evidence of oncogenic HRAS mutation in a case of oral IDP. This finding, together with the frequent and specific BRAF mutations in sialadenoma papilliferum reported in the recent literature, supports an active role of the MAP-kinase cascade in the pathogenesis of benign papillary neoplasms of terminal duct origin.

Diagnostic utility of p63/p40 in the histologic differentiation of salivary gland tumors: A systematic review

OBJECTIVE

Salivary gland tumors are a heterogeneous group of neoplasms with complex clinicopathologic behavior. These tumors often show an extremely diverse morphology and significant histologic patterns, making diagnosis a difficult task. Owing to the considerable differences in prognosis, treatment, and follow-up, accurately distinguishing these histologic mimickers is imperative. The aim of the present systematic review was to establish the diagnostic utility of p63/p40 immunostaining in histologic differentiation of salivary gland tumors.

STUDY DESIGN

An electronic search was carried out using MEDLINE by PubMed, Scopus, Google Scholar, Trip, Cochrane Library, and EMBASE databases. Articles in which both p63 and p40 immunohistochemical expressions were assessed were included for systematic review and their sensitivity and specificity were calculated. Risk of bias was analyzed for each study using the Quality Assessment of Diagnostic Accuracy Studies tool.

RESULTS

Ten eligible articles were included in the quantitative synthesis, which revealed a concordant positivity of p63 and p40 by nearly all cases of adenoid cystic carcinoma, pleomorphic adenoma, and mucoepidermoid carcinoma and most polymorphous adenocarcinomas showed discordant immunohistochemical expression (p63+/p40-).

CONCLUSIONS

The current evidence supports that integrated immunostaining of p63/p40 is a valuable adjunct for discerning enigmatic salivary gland tumors with true myoepithelial and/or squamous differentiation.

Sialadenoma Papilliferum of the Bronchus: An Unrecognized Bronchial Counterpart of the Salivary Gland Tumor With Frequent BRAF V600E Mutations

Sialadenoma papilliferum (SP) is a rare benign tumor of the salivary glands, and only 3 unequivocal cases of SP arising in the bronchus have been reported. We herein describe the histomorphologic and molecular features of 4 bronchial SP cases and discuss the differential diagnosis of this entity and the relationship with its clinicopathologic mimics, in particular, glandular papilloma and mixed squamous cell and glandular papilloma (GP/MP). We encountered 2 male and 2 female patients with bronchial SP (mean: 66.8 y old). All 4 tumors arose in the central bronchus and were characterized by a combination of surface exophytic endobronchial papillary proliferation and a submucosal multicystic component with complex architecture. The neoplastic epithelium consisted predominantly of nonciliated stratified columnar cells with ciliated, squamous, and mucinous cells present focally. While 2 tumors (50%) harbored a BRAF V600E mutation by molecular and immunohistochemical analysis, similar to GP/MP, no KRAS, HRAS, AKT1, or PIK3CA mutations were detected in any of the cases. Two patients were treated with limited resection, while 2 patients underwent lobectomy based on the diagnosis of adenocarcinoma or possible squamous cell carcinoma in situ in the preoperative biopsy. All survived without recurrence or metastasis for 23 to 122 months after treatment. SP can develop in the central bronchus as the bronchial counterpart of the salivary gland tumor and should be considered in the differential diagnosis of endobronchial tumors. In addition, some histologic resemblance and frequent BRAF V600E mutation raise the possibility of SP and GP/MP being on the same disease spectrum.

Sialadenoma papilliferum: clinicopathologic, Immunohistochemical, molecular analyses of new five cases and review of the literature

Background

Sialadenoma papilliferum (SP) is an extremely rare benign neoplasm of salivary glands. To explore and define the clinicopathological features of SP, we retrospectively analyzed 89 cases previously reported and five new cases.

Methods

The clinical features, histopathology, immunohistochemistry and molecular analysis of our cases were further performed and the related literatures were reviewed and analyzed.

Results

Combining 89 cases from the literature with our cases, the hard palate was the most common locations for SP. However, two of our cases were rarely located in the esophageal mucosa. Among all cases, the male gender was more affected, with the average age and median age of 61.8 and 62 years, respectively. Conventional histomorphologically, SP was characterized by complex papillary structures with a biphasic growth pattern of exophytic squamous component and endophytic glandular component. The glandular structures were lined by a double layer of epithelium composed of flattened or cuboidal basal cells and a cuboidal or columnar luminal cells formed papillary infoldings into the ductal lumina. Immunohistochemically, the luminal epithelial configurations showed strong expression of CK7 along the luminal cell membrane, while the basal myoepithelia displayed strong nuclear p63 expression. In both the glandular and squamous tumour components showed BRAF V600E-positive immunostaining and BRAF V600E mutation.

Conclusion

For the first time, we have comprehensively aggregated and analyzed 90 cases sialadenoma papilliferum from almost all previous publications, and further explored the clinicopathological features of SP; concordantly, this study demonstrated that SP shows a papillomatous growth pattern with exophytic and endophytic proliferation of ductal epithelium composed of double-layered cells harboring BRAF V600E mutation. Additionly, adequate treatment for SP is surgical excision, with a favorable prognosis in patients.

Sialadenoma Papilliferum

Sialadenoma papilliferum (SP) is a rare, benign salivary gland neoplasm sharing similar histopathologic features and harboring the same genetic alterations, BRAF V600E or HRAS mutations, with syringocystadenoma papilliferum. SP most commonly occurs in the hard palate and in older adults. Clinically, SP is most likely to be diagnosed as a squamous papilloma. Microscopically, SP shows an exophytic papillary epithelial proliferation and a contiguously endophytic ductal proliferation. Two distinct subtypes are identified: classic SP and oncocytic SP. Conservative surgical treatment seems to be adequate with a low recurrence. SOX10 immunohistochemistry and BRAF analysis may be useful in differential diagnosis.

A Rare Case of Intraductal Papilloma Arising from Minor Salivary Gland in the Floor of the Mouth

A 77-year-old woman with a rare oral intraductal papilloma arising from the minor salivary gland located on the floor of the mouth and causing the mucus retention is reported. Microscopically, the lesion was characterized by unicystic cavity exhibiting the lumen partially filled by papillary projections of the ductal epithelium with varying degree of oncocytic metaplasia. Based on the histopathological analysis, the differential diagnosis of oral intraductal papillomas and other ductal neoplasms of salivary origin are discussed.

Sialadenoma papilliferum: Bibliometric analysis

Background

Sialadenoma papilliferum is a benign rare condition of salivary glands showing a characteristic papillary growth of the ductal epithelium that ends up being confused with more frequent lesions of the oral cavity. Objectives: To perform a bibliometric analysis of all articles about Sialadenoma papilliferum in the oral cavity and to add a singular case report of Sialadenoma in the lower lip.

Material and Methods

A total of 36 publications referring to Sialadenoma papilliferum in the oral cavity from the PubMed platform was reviewed. The specific data were collected, and a bibliometric analysis was performed using Microsoft Excel. The results obtained were then compared with this new case report.

Results

The people most affected with sialadenoma were white males at the average age of 56. The lesion was asymptomatic, usually white or red, with an average size of 1.4 cm, and the palate was by far the most affected site. The majority of the lesions were excised, and only two cases indicated recurrence.

Conclusions

With surgical removal, Sialadenoma papilliferum has a favorable prognosis and no further treatment is required. Due to few recorded cases of recurrence, a long follow-up period is recommended to ensure that the lesion does not redevelop.

Key words:Sialadenoma papilliferum, salivary gland, oral cavity, bibliometric analysis.

Salivary Sialadenoma Papilliferum Consists of Two Morphologically, Immunophenotypically, and Genetically Distinct Subtypes

Papillary salivary gland neoplasms are rare tumors usually arising in the minor salivary glands of the oral cavity. Their classification has been historically confusing due to overlapping histologic features, but molecular analysis may clarify these entities. Sialadenoma papilliferum (SP) is a peculiar member of this group that demonstrates both an endophytic ductal and an exophytic squamous component. SP closely resembles syringocystadenoma papilliferum of the skin, a tumor which has recently been shown to harbor BRAF V600E or HRAS mutations. We sought to perform histologic and immunophenotypic analysis of a group of SP, along with BRAF and HRAS mutational analysis. We collected 13 SP cases from 7 females and 6 males ranging from 2 to 91 years (mean 62.8). Five exophytic ductal papillomas were also analyzed as controls. Histological analysis was performed along with immunohistochemistry for CK7, p63, and SOX10. BRAF VE1 immunohistochemistry was done in all tumors, and BRAF V600E and HRAS Sanger sequencing was successfully performed in all but two cases. Histologic analysis revealed that SP consisted not only of classic SP (9 of 13 cases) but also an oncocytic variant (4 of 13 cases) characterized by a glandular component that uniformly exhibited abundant granular cytoplasm and prominent nucleoli. By immunohistochemistry, all SP demonstrated luminal CK7 and basal p63 expression, but SOX10 was expressed only in conventional SP (9 of 9 cases). BRAF VE1 immunohistochemistry was positive in 9 of 9 conventional SP but 0 of 4 oncocytic SP; staining was present in both the exophytic and endophytic components. BRAF V600E mutational status was confirmed by Sanger sequencing in 11 cases (7 conventional and 4 oncocytic). The exophytic ductal papillomas were negative for BRAF mutations, and all tumors tested were negative for HRAS mutations. In summary, we demonstrated that SP consists of two variants: (1) conventional SP which is SOX10-positive and harbors BRAF V600E mutations similar to syringocystadenoma papilliferum of the skin; and (2) an oncocytic variant which is SOX10-negative and negative for BRAF mutations. We also demonstrated that both the endophytic glandular component and exophytic squamous components of conventional SP harbor BRAF V600E mutations and are therefore neoplastic.

Analysis of the Clinical Relevance of Histological Classification of Benign Epithelial Salivary Gland Tumours

INTRODUCTION

A vast increase in knowledge of numerous aspects of malignant salivary gland tumours has emerged during the last decade and, for several reasons, this has not been the case in benign epithelial salivary gland tumours. We have performed a literature review to investigate whether an accurate histological diagnosis of the 11 different types of benign epithelial salivary gland tumours is correlated to any differences in their clinical behaviour.

METHODS

A search was performed for histological classifications, recurrence rates and risks for malignant transformation, treatment modalities, and prognosis of these tumours. The search was performed primarily through PubMed, Google Scholar, and all versions of WHO classifications since 1972, as well as numerous textbooks on salivary gland tumours/head and neck/pathology/oncology. A large number of archival salivary tumours were also reviewed histologically.

RESULTS

Pleomorphic adenomas carry a considerable risk (5-15%) for malignant transformation but, albeit to a much lesser degree, so do basal cell adenomas and Warthin tumours, while the other eight types virtually never develop into malignancy. Pleomorphic adenoma has a rather high risk for recurrence while recurrence occurs only occasionally in sialadenoma papilliferum, oncocytoma, canalicular adenoma, myoepithelioma and the membranous type of basal cell adenoma. Papillomas, lymphadenoma, sebaceous adenoma, cystadenoma, basal cell adenoma (solid, trabecular and tubular subtypes) very rarely, if ever, recur.

CONCLUSIONS

A correct histopathological diagnosis of these tumours is necessary due to (1) preventing confusion with malignant salivary gland tumours; (2) only one (pleomorphic adenoma) has a considerable risk for malignant transformation, but all four histological types of basal cell adenoma can occasionally develop into malignancy, as does Warthin tumour; (3) sialadenoma papilliferum, oncocytoma, canalicular adenoma, myoepithelioma and Warthin tumour only occasionally recur; while (4) intraductal and inverted papilloma, lymphadenoma, sebaceous adenoma, cystadenoma, basal cell adenoma (apart from the membranous type) virtually never recur. No biomarker was found to be relevant for predicting recurrence or potential malignant development. Guidelines for appropriate treatment strategies are given.