Mammary analogue secretory carcinoma of salivary glands: diagnostic pitfall with distinct immunohistochemical profile and molecular features

Unmasking the rarity of mammary analogue secretory carcinoma of the minor salivary gland - A case report

INTRODUCTION

Mammary analogue secretory carcinoma (MASC) of the salivary gland was first described by Skálová et al. in 2010. It is often associated with a translocation, t(12;15)(p13;q25), which results in the fusion gene ETV6-NTRK3. Major salivary glands, primarily the parotid gland, are involved in 70 % of cases of MASC, while small salivary glands are involved in less than 25 % of cases. This report aims to consolidate in unveiling, diagnosing, and managing the rarity of MASC in the minor salivary gland and its existing knowledge and encourage new research on this increasingly important salivary gland malignancy.

PRESENTATION OF THE CASE

A 27-year-old female reported with a complaint of swelling on the right cheek region of face since 10 weeks. On bimanual palpation, a soft lobulated mass was appreciated beneath the healthy mucosal layer. The radiographic image (orthopantomogram) showed no obvious calcified mass. An excisional biopsy was planned and performed under local anesthesia. Microscopic and immunohistochemistry confirmed the tumor to be a MASC of minor salivary gland.

DISCUSSION

Due to their infrequency and multiplicity of histopathology, MASC presents difficulty in diagnosis. A key to determining diagnostic criteria for MASC is to study cellular morphology, cytoplasmic filament expression, and ultrastructural features of the tumor and apply this information to defining MASC.

CONCLUSION

MASC is an important molecularly defined entity of the salivary gland with low-grade malignant potential. Correct diagnosis is essential for appropriate treatment and will help to provide better information about this potentially low-grade malignant salivary gland neoplasm.

Do not Judge a book by its Cover: A Secretory Carcinoma Arising from a Salivary Gland Heterotopia in Laterocervical lymph-node

Heterotopia, the occurrence of specific tissues in ectopic sites during embryogenesis, includes the presence of salivary gland tissue in unusual locations. Salivary gland neoplasms arising from heterotopic sites are rare. Secretory Carcinoma (SC) is a rare salivary gland carcinoma characterized by ETV6-NTRK3 fusion gene, very rarely described in salivary gland heterotopia. Here a case of SC originating from salivary gland heterotopia in a neck lymph node is reported, together with a literature review.A 66-year-old male presented with a left neck mass. Imaging and fine needle aspiration cytology indicated a preliminary diagnosis of a benign/low-grade malignancy neoplasm.Following surgery (superficial parotidectomy and mass excision), histological examination revealed SC within an intranodal salivary heterotopia, confirmed by molecular analysis.Heterotopic salivary gland tissue (HSGT) is rare, and its association with neoplasms is even rarer. Tumours arising on HSGT, share histological similarities with those affecting orthotopic salivary glands. This unique case expands the understanding of SC occurrences on HSGT.

Salivary gland secretory carcinoma: A case presentation in minor salivary gland with review

INTRODUCTION AND IMPORTANCE

Salivary gland secretory carcinoma (SGSC) represents a rare malignant tumor of the salivary glands. Despite being regarded as low-grade tumors, they may manifest with metastases and a high-grade aggressive clinical behaviour. The literature on this subject is limited, and there is currently no standardized approach to treatment.

CASE REPORT

We report a rare case of SGSC in the palate of a 14-year-old female patient. The patient underwent excision, bilateral tonsillectomy and adjuvant radiotherapy.

CLINICAL DISCUSSION

A critical review of the literature was conducted with the objective of analysing the cases of intraoral SGSC that have been previously reported. A total of 23 articles, published between 2010 and 2024, were identified as being directly pertinent to the review, resulting in a total of 58 patients being included.

CONCLUSION

SGSC on the hard palate in a 14-year-old child is an exceedingly rare occurrence. These tumors can mimic other pathologies of the salivary glands clinically and microscopically, which can result in misdiagnosis and a delay in treatment.

Mammary analogue secretory carcinoma involving submandibular gland: Diagnostic pitfall with review of literature

ABSTRACT

Mammary analogue secretory carcinoma (MASC) is a recently defined entity among salivary gland tumors. MASC bores a striking resemblance to secretory carcinoma of breast along with the characteristics of ETV6-NTRK3 translocation. Hence, the entity was designated as MASC and was formally included in the 4th edition of World Health Organization classification of head and neck tumors in 2017. To the best of our knowledge, around 12 cases of MASC have been described in the Indian literature. MASC commonly involves parotid gland (70%). Involvement of submandibular gland is still rarer (7%). Prognosis of MASC is comparable to other low grade salivary gland malignancies; however, aggressive behavior has also been reported in few cases. This case is one of the very few reported cases describing MASC with detailed clinical, cytology, and microscopy findings along with special stains and immunohistochemistry.

Non Indigenous Mammary Secretory Carcinoma of Parotid Gland - An Unusual Presentation

Mammary analog secretory carcinoma (MASC) is a relatively rare, low-grade tumor affecting the salivary glands. We report a 62-year-old female who was diagnosed with MASC of the left parotid gland and underwent left Total conservative parotidectomy with condylectomy and reconstruction with right anterolateral free flap and left facial nerve (frontal branch) reconstruction with a cable graft. As there is no standard treatment protocol developed for the management of MASC, this report focuses on the various management options that have been followed to date.

Salivary Gland Secretory Carcinoma; Review of 13 Years World-Wide Experience and Meta-Analysis

OBJECTIVES

Secretory Carcinoma is a malignant salivary gland tumor, initially described in 2010. This rare tumor is associated with the translocation t(12;15) (p13;q25), resulting in the fusion gene ETV6-NTRK3. Since this tumor is quite rare, most publications describe only small cohorts of patients. We aimed to investigate the clinical, pathological, and prognostic features of this newly defined malignant entity.

DATA SOURCES

Pubmed, Google Scholar, and Web of Science databases.

REVIEW METHODS

All published articles between 2010 and 2023 were reviewed. Search terms included the terms "Mammary Analogue Secretory Carcinoma" and "Secretory Carcinoma". All articles published in English reporting on Secretory Carcinoma of salivary glands were retrieved.

RESULTS

One-hundred and 12 retrospective articles reporting a total of 674 patients were included, with 52% males and a mean age of 44.9 ± 18.9. The event rate for patients with advanced-stage disease (Stage 3/4) at presentation was 24.1% (95% CI 17.6%-31.9%, I2  = 9.2%), 14.6% for regional metastases (95% CI 10.5%-20%, I2  = 12%), and the event rate of distant metastasis was 8.4% (95% CI 5.5%-12.7%, I2  = 4.2%). Adjuvant radiotherapy was administered for 30.3% of patients (95% CI 24.1%-37.2%, I2  = 21.5%). The recurrence rate was 19% (95% CI 15.1%-23.8%, I2  = 5%). Survival outcomes showed a 17.2% death of disease rate for Secretory Carcinoma patients (95% CI 13.5%-21.8%, I2  = 7.3%).

CONCLUSIONS

Secretory Carcinoma is a rare and relatively newly defined entity arising in the parotid gland most commonly. Characterized as a low-grade tumor, the majority of patients are diagnosed at an early stage, without regional or distant disease, and the prognosis is relatively good.

LEVEL OF EVIDENCE

NA Laryngoscope, 134:1716-1724, 2024.

Salivary gland secretory carcinoma presenting as a cervical soft tissue mass: a case report

BACKGROUND

Secretory carcinoma (SC) has been described as a distinct salivary gland tumor in the fourth edition of the World Health Organization (WHO) classification of head and neck tumors. SC is generally considered as a slow-growing low-grade malignant tumor, while several cases have been reported with high-grade features, and even metastases in the literature up until now. In this article, a soft tissue SC case is discussed with high-grade microscopic features and neural invasion. A review of the salivary gland SC cases with aggressive behavior is also debated.

CASE PRESENTATION

A 65-year-old Caucasian man presented with a left neck mass for the past six months. The imaging studies demonstrated a very large cystic cervical mass (46 × 23 mm) with papillary projections in the anterolateral aspect of the left neck zone Vb. He underwent left radical neck dissection (level I-V) and was followed up for 12 months with the diagnosis of Secretory carcinoma.

CONCLUSION

Although SC generally has a good outcome, multiple recurrences and unusual metastases may occur, which should be considered by either the pathologists or clinicians.

Recent developments in the pathology of primary pulmonary salivary gland-type tumours

Primary pulmonary salivary gland-type tumours are rare neoplasms that are thought to arise from seromucinous glands that are located in the submucosa of large airways. These neoplasms have clinical and pathologic features that are distinct from other pulmonary neoplasms. The majority of primary pulmonary salivary gland-type tumours are malignant, with the most common entities being mucoepidermoid carcinoma, adenoid cystic carcinoma, and epithelial-myoepithelial carcinoma. Less commonly seen are myoepithelial carcinoma, hyalinizing clear cell carcinoma, acinic cell carcinoma, secretory carcinoma, salivary duct carcinoma, intraductal carcinoma, and polymorphous adenocarcinoma. Benign salivary gland-type tumours of the lung include pleomorphic adenoma and sialadenoma papilliferum. Morphologic, immunophenotypic, and molecular features of these neoplasms are largely similar to salivary gland tumours elsewhere, and therefore the exclusion of metastatic disease requires clinical and radiologic correlation. However, the differential diagnostic considerations are different in the lung. The distinction of salivary gland-type tumours from their histologic mimics is important for both prognostication and treatment decisions. Overall, salivary gland type-tumours tend to have a more favourable outcome than other pulmonary carcinomas, although high-grade variants exist for many of these tumour types. Recent advances in our understanding of the spectrum of salivary gland-type tumours reported in the lung and their diversity of molecular and immunohistochemical features have helped to refine the classification of these tumours and have highlighted a few differences between salivary gland-type tumours of the lung and those primary to other sites.

Utility of MUC4 in the diagnosis of secretory carcinoma of salivary glands

Salivary gland tumors are diverse in morphology and both benign and malignant tumors may pose diagnostic challenges especially in small biopsies. Secretory carcinoma (SC) is histologically characterized by microcysts, follicles, solid growth pattern and occasional papillary structures, and absence of zymogen granules. SC is molecularly defined by the presence of novel gene fusion ETV6::NTRK3. Among the positive stains (S100 and mammaglobin), MUC4 is now another promising marker for the diagnosis of SC, that would enable the pathologists to exclude other morphologically close simulators. Aim of this study was to report clinicopathological features and assess utility of MUC4 in the diagnosis of SC. MUC4 was performed on 22 cases of SC. Glass slides were reviewed to record morphological patterns and staining of S100, mammaglobin, DOG1 and MUC4. Age ranged from 9 to 63 years with mean age of 34.41 ± 16.28 years. The male: female ratio was 72.7 %:27.3 %. The majority occurred in major salivary glands. A combination of patterns was seen; microfollicles were the most prevalent (90 %) followed by papillary-cystic and macrofollicles. MUC4 was positive in 19/21 (90 %) cases with almost equal number of 2+ and 3+ staining. MUC4 was negative in all cases of acinic cell carcinoma, polymorphous adenocarcinoma, adenoid cystic carcinoma, salivary duct carcinoma, myopepithelioma and myoeithelial carcinoma, cystadenoma and cribriform adenocarcinoma and all except 3 cases of mucoepidermoid carcinoma tested. Overall sensitivity of MUC4 was 95.4 %, specificity 90 %, p-value being <0.01, positive predictive value 87.5 % and negative predictive value 96.4 %. A characteristic cytoplasmic granular pattern was observed in 76.1 % tumors. S100 and mammaglobin were positive in all the performed cases. DOG1 was positive in 6/11 (28.5 %) tumors. In conclusion, MUC4 is a useful addition to a diagnostic immunohistochemical panel for SC, and to distinguish it from close potential mimickers such as acinic cell carcinoma, especially in practice settings where molecular testing is unavailable.

MASC Gets UNMASKED: Visiting a Rare Tumor with Emphasis on Cytomorphological Features

Background

Secretory carcinoma (SC) is a newly described entity which has been often misdiagnosed earlier as acinic cell carcinoma on cytology. Diagnosing SC was initially based upon identifying the ETV6:NTRK3 fusion gene with the help of fluorescence in situ hybridization (FISH). Lately, with more knowledge of the reliable histomorphology, cytology, and immunohistochemistry features, definitive diagnosis can be confidently made without the help of FISH in almost every case.

Materials and Methods

Six histologically confirmed cases of SC were studied. The cytology slides of all the six cases were retrieved and reviewed to identify the characteristic features which could have helped in raising the possibility of SC on fine needle aspiration cytology itself. Cell blocks were also studied, wherever available.

Results

Patients were all male with average age of 35.2 years. The six cases in the current study demonstrated at least focal cytoplasmic vacuolization of varying sizes, papillae formations, and bland nuclear features on fine needle aspirate smears. It was also seen that S-100 and mammaglobin immunohistochemistry (IHC) are very helpful in confirming the diagnosis.

Conclusions

The results of the current study highlight the cytomorphological features which may help in clinching the diagnosis SC on cytology itself. They also highlight certain cytological features which help to rule out the other differential diagnoses.

Salivary Gland Neoplasms With a Unique Trabecular Histology and MAML2 Translocation : A Trabecular Variant of a Mucoepidermoid Carcinoma

Mucoepidermoid carcinomas (MECs) are the most common salivary gland malignancy and have a diverse histology. Many histologic variants of MEC have now been confirmed with characteristic molecular alterations involving CRTC1::MAML2 or CRTC1::MAML3 translocations. We here report a series of 7 trabecular variants of MEC which showed a predominant trabecular or nested pattern with either focal glandular differentiation or clear cell change and keloid-like fibrosis in the background. In addition, these tumors were either negative or showed only focal positivity for p63. Such features are not characteristic of known disease entities and resulted in an initial misdiagnosis of adenocarcinoma, not otherwise specified, or low-grade to intermediate-grade MEC with uncertainty. The patients' ages in our cohort ranged from 26 to 55 years with a female predominance (5/7). The tumors were located in the parotid gland (n=3), base of tongue (n=2), hard palate (n=1), and parapharyngeal space (n=1), with a median size of 1.5 cm. All 7 cases showed an MAML2 split pattern on fluorescence in situ hybridization analysis, and both RNA and whole-genome sequencing presented CRTC1::MAML2 translocation. All 7 cases showed a solid-predominant histology, and 3 cases displayed extracapsular extension. There were no other signs of high-grade histology and no recurrences or deaths occurred over a follow-up period of up to 79 months. We thus propose a unique trabecular variant of MEC that has atypical histologic and immunohistochemical features.

Secretory carcinoma of major and minor salivary glands with ETV6-NTRK3 gene fusion: overcoming misdiagnosis in the era of tumour-agnostic therapy with TRK inhibitors

Introduction

Secretory carcinoma (SC) of the salivary gland is an extraordinarily rare tumour. Accurate diagnosis of SC is crucial for understanding the clinical course, prognosis, and selection of optimal therapy. The aim of this research was to analyse retrospectively the clinical and pathological characteristics of patients diagnosed with SC of the salivary gland from 2017 onwards, which aligns with its addition to the World Health Organization classification.

Material and methods

We conducted a retrospective, single-centre, clinicopathological analysis of patients diagnosed with SC of the salivary gland between 2017 and 2022. The analysis included the evaluation of NTRK3 gene rearrangements and immunohistochemical (IHC) profiling.

Results

The study included 6 patients, comprising 4 women and 2 men. The average age of the patients was 50 years (standard deviation 26). Three cases presented with tumours in the parotid gland, while one case each involved the submandibular gland, sinonasal tract, and buccal mucosa. Interestingly, despite the characteristic IHC profile, each case was initially diagnosed as a different type of salivary gland cancer. Next-generation sequencing analysis was performed in 3 cases, revealing the presence of the ETV6-NTRK3 fusion gene. This cohort notably features an intriguing case: the youngest patient documented in literature, distinguished by extended follow-up and delayed recurrence.

Conclusions

In summary, emphasizing the risk of misdiagnosis is pivotal in the context of SC of the salivary gland, which can manifest across diverse glandular sites. Accurate diagnosis, underscored by the assessment of NTRK3 gene rearrangements, assumes a critical role in guiding effective management and treatment decisions.

Prognostic factors in mammary analogue secretory carcinomas of the parotid gland: Systematic review and meta-analysis

Mammary analogue secretory carcinomas (MASCs) of the parotid gland are considered as low-grade malignancies with good clinical outcome but lacking data regarding prognostic factors. We performed meta-analysis assessing prognostic factors for disease-free survival (DFS) and overall survival (OS) in 256 patients with MASCs of the parotid gland. A total of 73 studies have met the inclusion criteria and 76.3% of patients were seen with T1 and T2 tumors and negative neck nodes. Lymph node metastasis (57.4%) and distant recurrences (46.2%) were particularly found in T4 tumors (p < 0.001). DFS at 5 and 10 years was 77.9% and 47.2% compared to 88.1% and 77.2% for OS at the same time points. Male sex, T3-T4 tumors, and recurrent disease represented independent worse prognosticators for survival outcome. Altogether, parotid gland MASCs show good long-term outcome, but T4 tumors behave significantly more aggressive and require extended treatment strategies along with close follow-ups.

Diagnosis and treatment of secretory carcinoma arising from the oral minor salivary gland: Two case reports

INTRODUCTION

Secretory carcinoma (SC) is a malignancy of the salivary glands, which is similar to SC of the breast regarding its association with neurotrophic tyrosine receptor kinase fusion-positive gene. SC is a recently described salivary gland tumor, and there are a few reports describing oral minor salivary gland-derived SC. We reported two cases of SC in the oral cavity and reviewed the literature.

PATIENT CONCERNS

The patients included a 65-year-old Japanese woman who presented with a mass of the upper lip and an 84-year-old Japanese man who presented with a mass on the buccal mucosa.

DIAGNOSIS

Diagnosis was based on histomorphological and immunohistochemical findings and identification of a specific translocation of the ETS variant 6-neurotrophic receptor tyrosine kinase 3 gene fusion. Case 1 was finally diagnosed using reverse transcription-polymerase chain reaction with formalin-fixed paraffin-embedded tissue samples, while case 2 was diagnosed using fluorescence in situ hybridization analysis.

INTERVENTIONS AND OUTCOMES

In case 1, excisional biopsy was done and there was no recurrence observed in five-year follow-up. In case 2, tumor resection was done and there was no recurrence observed in two-year follow-up.

CONCLUSION

It is highly likely for many cases of SC to be initially diagnosed as acinic cell carcinoma (AciCC) owing to their similar histological findings. The treatment strategy for minor salivary gland-originated SC is similar to that of AciCC; however, SC is often highly malignant and involves a high risk of cervical lymph node metastasis. Thus, establishing an accurate diagnosis together with pathologists and confirming the presence of the ETS variant 6-neurotrophic receptor tyrosine kinase 3 fusion gene using genetic analysis is important.

MR Imaging of Salivary Gland Tumors

Neoplasms of the salivary glands are characterized by their marked histologic diversity giving them nonspecific imaging findings. MR imaging is the best imaging modality to evaluate salivary gland tumors. Multiparametric MR imaging combines conventional imaging features, diffusion-weighted imaging, and perfusion imaging to help distinguish benign and low-grade neoplasms from malignant tumors; however, a biopsy is often needed to establish a definitive histopathologic diagnosis. An awareness of potential imaging pitfalls is important to prevent mistakes in salivary neoplasm imaging.

Clinicopathological characteristics and outcomes of 23 patients with secretory carcinoma of major salivary glands

This retrospective study investigated the clinicopathological characteristics of secretory carcinoma of salivary glands (SCSG) in 23 patients with histopathologically confirmed SCSG between January 2010 and December 2020. In total, 13 males and 10 females (ratio, 1.3:1) aged 10 − 69 years (median, 45 years) were enrolled in this study; the average disease duration was 2.44 years (0.25–20 years). Twenty-one patients (91.3%) had SCSG in the parotid gland, and two (8.7%) in the submandibular gland. All patients had single nodules of diameters 0.8–4.8 cm (average 2.6 cm); five with lymph node metastases, and two with distant metastases. Immunohistochemically, tumors stained positive for S-100, mammaglobin, CK7, GATA3 and pan-Trk, and negative for DOG1, P63, and calponin, with Ki-67 positivity from 1 to 50%. ETV6 gene rearrangement was confirmed in 15 patients. All patients underwent oncological resection, four had radioactive particles implanted postoperatively, one received chemotherapy, and seven underwent chemoradiotherapy. Six patients had regional recurrences, two distant metastases, and one died before the last follow-up. SCSGs are typically indolent, with a low locoregional recurrence rate and excellent survival. Prognosis is correlated to clinical stage, pathological grade, and surgical procedures.

A systematic review of secretory carcinoma of the salivary gland: where are we?

OBJECTIVE

The aim of this systematic review was to describe the epidemiology, diagnostic criteria, differential diagnosis, treatment, prognostic factors, and treatment outcomes of secretory carcinoma.

STUDY DESIGN

A comprehensive search of Lilacs, PubMed, Science Direct, and Web of Science databases was conducted to identify all case reports, letter to the editor, and histopathologic reclassifications regarding salivary gland secretory carcinoma published in English, Spanish, French, and Portuguese.

RESULTS

The final analysis included 119 studies, which totaled 642 secretory carcinoma diagnoses, with 239 case reports and 403 diagnostic reclassifications, mostly in the United States. The age range was 5 to 87 years, and cases were predominantly in males (58.7%) and mostly affecting the parotid glands (73.7%). The disease usually presents as a slow-growing, painless mass. The main differential diagnosis is acinic cell carcinoma, and the tumor is usually treated with surgery. The prognosis is considered favorable, although there have been reports of local recurrences, distant metastases, and deaths.

CONCLUSIONS

It is important that clinicians become aware of this salivary gland neoplasm and report clinical data, clinical course, management and long-term follow-up. There is an urgent need to conduct more clinical trials, especially on tropomyosin receptor kinase (TRK) inhibitors and other potential target therapy modalities.

Secretory Carcinoma of the Oral Cavity: A Retrospective Case Series with Review of Literature

Secretory carcinoma (SC) is an uncommon salivary gland neoplasm of the oral cavity that microscopically may mimic acinic cell carcinoma (ACC) and mucoepidermoid carcinoma (MEC). This study describes a series of SC in minor glands with a literature review. We performed a retrospective search for oral SC, within the archives of the University of Florida, Oral Pathology and Surgical Pathology Biopsy services from 2010 to 2018. A total of 10 SCs were identified in the oral and maxillofacial region, four of which were in the minor salivary glands. The demographic, clinical, histological, and molecular findings were aggregated for all 4 cases. Patient age varied from 30 to 60 years, with an average of 45 years. Two cases each were in female and male patients. Two cases presented on the labial mucosa, and one each on the hard and soft palate. Immunohistochemical (IHC) staining showed mammaglobin positivity in all cases, GATA3 positivity in two cases, S100 positivity in three cases, and SOX10 positivity in only one case. Fluorescence in situ hybridization demonstrated positivity for ETV6-NTRK3 fusion in 4 cases. Although oral SC is rare, pathologists should be aware of the histologic overlap between the SC and other salivary gland neoplasms such as ACC and MEC. A judicious application of IHC staining would aid in diagnosis. SC should be considered in the differential diagnosis for intraoral salivary gland tumors.

MUC4 is a valuable marker for distinguishing secretory carcinoma of the salivary glands from its mimics

AIMS

Secretory carcinoma (SC) (synonym: mammary analogue secretory carcinoma) is a low-grade salivary gland tumour that occurs in both major and minor salivary glands. SC is known for its wide morphological, architectural and immunohistochemical spectrum, which overlaps with those of several salivary gland neoplasms, including acinic cell carcinoma (AciCC) and intercalated duct-type intraductal carcinoma (IDC) in major salivary glands, and polymorphous adenocarcinoma (PAC) in minor salivary glands. These tumours share with SC some morphological features and SOX10 immunoreactivity; also, with the exception of AciCC, they all coexpress S100 and mammaglobin.

METHODS AND RESULTS

We compared MUC4 and mammaglobin expression in 125 salivary gland carcinomas (54 genetically confirmed SCs, 20 AciCCs, 21 PACs, and 30 IDCs) to evaluate the potential of these two markers to differentiate these entities. Moderate to strong diffuse MUC4 positivity was detected in 49 SCs (90.7%), as compared with none of the IDCs and PACs. In contrast, mammaglobin was frequently expressed in SCs (30 of 36 cases; 83.3%), IDCs (24/28; 85.7%), and PACs (7/19; 36.8%). Two of three high-grade SCs lost MUC4 expression in the high-grade tumour component. No significant correlation was found between MUC4 expression and the fusion variant in SC (ETV6-NTRK versus non-ETV6-NTRK).

CONCLUSION

The results of our study identify MUC4 as a sensitive (90.7%) and specific (100%) marker for SC, with high positive (100%) and negative (93.4%) predictive values. Thus, MUC4 may be used as a surrogate for SC in limited biopsy material and in cases with equivocal morphology.

Acinic cell carcinoma of the parotid gland: from pathogenesis to management: a literature review

PURPOSE

Acinic cell carcinoma (ACCs) is uncommon malignant epithelial neoplasm of the salivary glands; the most common presentation is a well-defined painless solid mass. Diagnosis of ACCs is frequently complicated, due to its similarity with benign tumors.

METHODS

A review of the literature available on ACCs was carried out. Studies were sourced from PubMed with searching of relevant headings and sub-headings and cross-referencing.

RESULTS

There are no clear characteristics of ACCs found on CT, MRI and ultrasound imaging. The management of the ACC, a rare malignancy of the parotid gland, is often difficult and controversial. Radical surgery is the best treatment option. The role of radiotherapy remains controversial: the precise indications and oncologic effects of adjuvant radiotherapy in ACC of the parotid gland are not well known. There is insufficient literature regarding the chemotherapy for metastatic ACC.

CONCLUSION

Knowledge about ACC, a rare malignancy of parotid gland, has changed over the past few decades. More clinical randomized works would be needed, both to assess the real effectiveness of radio and chemotherapy and to have an unanimous consensus about their indications.

Characterization of novel genetic alterations in salivary gland secretory carcinoma

Secretory carcinoma is a salivary gland tumor with a characteristic chromosomal translocation that results in an ETV6-NTRK3 fusion gene. Secretory carcinoma shows relatively frequent rates of lymph-node metastasis and tumor recurrence and has a characteristic histology. Except for the ETV6 translocation, genomic alterations in secretory carcinoma have not been reported. In the present study, we characterized the novel recurrent genetic mutations of secretory carcinoma. On the basis of histology, immunohistochemistry, and ETV6 gene break-apart fluorescence in situ hybridization assays, 22 tumors were classified as secretory carcinomas (19 ETV6 translocation-positive and 3 ETV6 translocation-negative secretory carcinomas) and their clinicopathologic characteristics were reviewed. Targeted deep sequencing analyses were performed on 20 secretory carcinomas (17 ETV6 translocation-positive and 3 ETV6 translocation-negative secretory carcinomas) to investigate their genetic alterations. The A16V (C→T) mutation in PRSS1, which encodes a cationic trypsinogen and has a mutation associated with hereditary pancreatitis and pancreatic adenocarcinoma, was observed in 40% (8/20) (7/17 of ETV6 translocation-positive and 1/3 of ETV6 translocation-negative secretory carcinomas). Pathogenic variants of MLH1, MUTYH, and STK11 were also identified. Variants of uncertain significance included mutations in KMT5A. These novel characteristic genetic alterations may advance current understandings of secretory carcinoma tumorigenesis and progression, leading to improved diagnoses and treatment strategies.

[Secretory carcinoma of the salivary gland (mammary analogue secretory carcinoma) in children]

Secretory carcinoma of the salivary gland is a tumor that was first described less than 10 years ago and that mainly occurs in the parotid salivary gland in the elderly. Analyzing the literature over 8 years since the first description of the tumor identifies the main clinical, morphological, and genetic signs of the diagnosis of secretory carcinoma with a focus on the pediatric population. Four new cases of secretory carcinoma of the salivary glands, which have been diagnosed in children of the youngest age encountered in the literature, are also described.

Outcomes of treatment of mammary analogue secretory carcinoma of the parotid gland

Mammary analogue secretory carcinoma (MASC) of the salivary gland is a newly-described, rare, malignant tumour. Few patients present with MASC of the parotid gland, so the exact characteristics, outcomes of treatment, and prognosis are unknown. The aim of this study was to analyse the clinical features and outcomes of treatment of MASC of the parotid gland in patients being treated at a single hospital. Five patients with histopathologically-confirmed MASC of the parotid gland between January 2015 and August 2018 were retrospectively enrolled. In all cases preoperative fine-needle aspiration cytology had failed to provide an accurate diagnosis. All patients underwent a macroscopically complete oncological resection. Two patients had postoperative radiotherapy (RT). On immunohistochemical examination all tumours stained for S-100 and mammaglobin but not for DOG1. There were no regional recurrences or distant metastases in any of the patients at their last follow-up. We obtained good results for patients with MASC of the parotid gland with surgical treatment and postoperative RT.

Mammary analogue secretory carcinoma of the minor salivary gland: report of two cases

Mammary analogue secretory carcinoma (MASC) is a recently described salivary gland tumour notable for a balanced chromosomal translocation t(12;15)(p13;q25) that contributes to ETV6 gene rearrangements. It was first reported in 2010 by Skalova et al. with histological features resembling secretory carcinoma of the breast and was acknowledged and referred to as "secretory carcinoma" in the updated 2017 WHO classification. It is reported that MASC accounts for <0.3% of all salivary gland tumours, with a finite number of published reports on it. MASC has a range of histological features and clinical behaviours. The histopathological diagnosis of MASC can be difficult with current immunohistochemical methods. One case was located in the left palate, and 1 case was located in the soft palate. The maximum diameter of the tumour was 1.4~3.7 cm. CT demonstrated a mass that had not invaded into the palate bone, and the patients underwent palate neoplasm expanded ectomy without neck dissection or postoperative radiation therapy. Histopathological examination revealed that the tumour cells consisted of a mixed arrangement of microcystic, papillary-cystic, follicular, and solid lobular growth patterns. Eosinophilic cytoplasm and intraluminal or intracytoplasmic colloid-like secretions were observed. The final pathology confirmed the diagnosis of MASC with immunohistochemically neoplastic cells staining positive for S-100 and mammaglobin. The patients were asymptomatic at their 12-month follow up. More studies are needed to identify the typical behaviour of this tumour and establish the standard treatment regimen. This study aims to reinforce the awareness of this tumour by analysing its clinicopathologic features, immunophenotype, and diagnosis.

Secretory Carcinoma of Minor Salivary Gland in Buccal Mucosa: A Case Report and Review of the Literature

Secretory carcinoma (SC) of the salivary gland was recently added to the fourth edition of the World Health Organization classification of head and neck tumors. Some salivary tumors, including acinic cell carcinoma, have been reclassified as SC. Most of these tumors are located on the parotid gland with very few cases reported in the minor salivary glands of the buccal mucosa. Herein, we present a case of SC of buccal mucosa, which appeared clinically as a benign lesion in a 54-year-old Japanese female patient. Histopathologically, the tumor cells presented with an eosinophilic cytoplasm with microcytic structure along with eosinophilic secretory material and hemosiderin deposit. Immunohistochemical staining revealed strongly positive staining for S100, vimentin, and mammaglobin and negative staining for DOG-1. The tumor was finally diagnosed as secretory carcinoma of the buccal mucosa. We present a review of the medical literature of SC arising from minor salivary glands. We found only 15 cases of SC of buccal mucosa out of 63 cases of SC in the minor salivary glands. They showed good prognoses and only one case of SC in the buccal mucosa exhibited local recurrence and lymph node metastases.