Mammary analogue secretory carcinoma of salivary gland origin: an update and expanded morphologic and immunohistochemical spectrum of recently described entity

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 of the Parotid at Younger Age: An Unusual Entity

Introduction

Malignancy of parotid glands is uncommon in the pediatric age group. Among the various subtypes, mammary analogue secretory carcinoma (MASC) of parotid is an unusual variant that mimics pathologically those of mammary secretory carcinoma of the breast. It usually presents as a slow-growing, painless parotid mass.

Case Summary

We had a 17-year-old female patient who presented with recurrent swelling in her right parotid region, which was adherent to the skin focally. Contrast-enhanced MR showed a solid multi-cystic lesion in her right parotid region. Pre-operative cytopathology was inconclusive. She underwent total parotidectomy with level II nodal clearance, and the histopathology was suggestive of mammary analogue secretory carcinoma.

Discussion

MASC is considered to be a low-grade, slow-growing malignancy when presented at an earlier stage. Our patient was kept under close follow-up, and she is disease-free at nearly thirty months post-operatively.

Secretory Carcinoma of the Parotid Gland Presenting as a Persistent Cystic Parotid Mass: A Case Report

Secretory carcinoma (SC) of the salivary glands, previously termed mammary analog secretory carcinoma (MASC), is a rare, low-grade malignant tumor of the salivary glands that closely resembles SC of the breast. This case report discusses parotid SC in a 40-year-old female patient who presented with recurrent parotid swelling. The report aims to demonstrate the importance of recognizing this rare tumor, raising awareness, and adding this case to world literature.

Secretory carcinoma of the minor salivary gland: An in-depth case report

A 56-year-old female was referred to our service for management of a malignant salivary gland neoplasm with compromised margins that had been biopsied previously at another service. The patient reported a twenty-year history of a lesion in the oral cavity with progressive and exuberant growth over the past two years, associated with local pain and dyspnea. Physical examination revealed an erythematous, ulcerated, and hemorrhagic lesion measuring approximately 3 cm on the left soft palate and tonsillar pillar. Computed tomography revealed an expansile lesion in the topography of the left soft palate, growing predominantly toward the lumen of the nasopharynx and partially invading the left wall of this region. The patient underwent surgery and histopathologic examination revealed an infiltrative and aggressive epithelial neoplasia with large vacuolated and eosinophilic cytoplasm, vesicular nuclei, and prominent nucleoli. The neoplastic cells were arranged in a solid, microcystic, tubular, and follicular pattern with eosinophilic luminal secretion. Mitotic figures were frequent and all margins were affected by the neoplasia. Morphologic and immunohistochemical features supported the diagnosis of secretory carcinoma, and the patient is currently being followed for further therapeutic intervention.

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.

The genetic and immune features of salivary gland secretory carcinoma with high-grade transformation

OBJECTIVES

To compare the clinicopathological, molecular, and immune features of conventional and high-grade transformation (HGT) secretory carcinoma (SC) in salivary glands.

MATERIALS AND METHODS

The clinicopathological data of 88 cases including 74 conventional SCs and 14 SCs with HGT were reviewed. Targeted next-generation sequencing was performed in 11 SCs with HGT and 7 conventional SCs. The level of PD-L1 and CD8+ TILs was determined by immunohistochemistry.

RESULTS

Compared with the conventional group, the rates of nodal metastasis, local recurrence, distant metastasis and mortality were significantly higher in the HGT cohort. Mutations of ARID1A/B, KMT2A, HOXD13, NRG1 and ETV6 genes were identified in HGT SCs. A recurrent E307G mutation in GATA6 gene was also observed in two cases. Two deceased HGT patients with distant metastasis harboured NOTCH3 mutations. ETV6-RET translocation was prone to occur in the HGT SCs. Additionally, PD-L1 expression was low, and CD8+ TILs were sparse in most HGT cases.

CONCLUSION

Our findings reveal novel gene alterations involved in the progression of HGT in SCs. Most HGT SCs patients cannot benefit from PD-L1 blocking and may be approached with a distinct treatment strategy including the lymph node dissection and application of molecular target drugs in precision oncology.

Secretory Carcinoma of the Philtrum of the Upper Lip: A Case Study

The parotid, submandibular, and sublingual salivary glands are the major salivary glands in the mouth. Cancers that arise in these glands are relatively uncommon, usually benign, and rarely metastasize. We present a unique case of a 17-year-old male diagnosed with high-grade secretory carcinoma of the salivary gland that was generally asymptomatic except for a persistent rash. The patient reported no significant past medical, family, or social history. A multidisciplinary team efficiently diagnosed and treated the cancer with histopathology, MRI, tumor excision, lymphadenectomy, and adjuvant treatment. Despite the rarity of the cancer, which was found in a high-grade regionally advanced disease, in an uncharacteristically young patient, the patient was effectively treated with adjuvant chemoradiotherapy without treatment-related complications.

Oncocytoid Salivary Tumors: Differential Diagnosis and Utility of Newly Described Immunohistochemistry

BACKGROUND

Oncocytoid salivary tumors include several entities such as oncocytoma, Warthin tumor, secretory carcinoma (SC), salivary duct carcinoma (SDC), acinic cell carcinoma (AciCC), oncocytic mucoepidermoid carcinoma (OMEC), intraductal carcinoma, and epithelial myoepithelial carcinoma (EMC). This review investigates the differential diagnosis of oncocytoid salivary tumors and explore the role of newly described immunostains as valuable tools for their diagnosing and potentially guiding treatment options.

METHODS

We assess the utility of incorporating new immunohistochemical markers in routine practice to aid in diagnosing oncocytoid salivary tumors and potentially provide treatment options.

RESULTS

In SDC, AR and Her2 immunostains are utilized as diagnostic tools and biomarkers for selecting patients who might benefit from Androgen-deprivation therapy (ADT) and HER2-targeted therapy. Furthermore, nuclear Pan-Trk immunostaining can aid in diagnosing SC. Additionally, NR4A3 immunostaining has been shown high sensitivity and specificity in identifying AciCC in both surgical and cytologic specimens. Similarly, RAS Q61R mutant-specific immunostaining, detected in EMC, may offer a cost-effective diagnostic marker for this tumor. Although further studies are required to evaluate the role of BSND, this marker has been reported to be positive in Warthin tumor and oncocytoma, aiding in differentiating them from other oncocytoid tumors, particularly OMEC. In addition, BRAFV600E mutant-specific immunostaining can serve as a diagnostic and potentially therapeutic marker for oncocytic intraductal carcinoma in mutation positive cases.

CONCLUSION

Oncocytoid salivary tumors may have overlapping morphologies, posing diagnostic challenges for pathologists. Recently described immunohistochemical markers may offer valuable tools for diagnosing and potentially guiding treatment options for these tumors.

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.

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.

Acinic Cell Carcinoma in the 21st Century: A Population-Based Study from the SEER Database and Review of Recent Molecular Genetic Advances

BACKGROUND

Acinic cell carcinoma (AciCC) comprises 6-7% of all salivary gland neoplasms and is the second most common salivary gland malignancy in children. Like many salivary gland carcinomas, it is considered low grade but occasionally it behaves aggressively. Understanding the risk factors associated with recurrence, metastasis, and death is important to determine the counseling and management of individual patients. Older population-based studies are presumed to have been confounded by the misclassification of other neoplasms as AciCC, in particular secretory carcinoma and cystadenocarcinoma. Since diagnostic tools to reliably separate these entities have been available for over a decade, reevaluation of epidemiologic data limited to the 21st century should allow a better characterization of the clinicopathological characteristics of AciCC.

METHODS

Our study extracted data from the Surveillance, Epidemiology, and End Results (SEER) database for the period 2000 to 2018. Cox regression model analysis was performed to identify risk factors independently affecting survival.

RESULTS

Data for 2226 patients with AciCC were extracted from the database. Most patients were females: 59%, and white: 80.5%, with a mean age at diagnosis of 51.2 (SD ± 18.7) years. Most cases (81%) were localized at presentation. Tumor size was less than 2 cm in 42%, 2-4 cm in 47%, and >4 cm in 11%. Low-grade tumors had 5-year survival > 90%, whereas high-grade tumors had survival < 50%. Of the patients with known lymph node status only 7.3% had nodal metastases. Distant metastases were documented in 1.1%, involving lungs 44%, bone 40%, liver 12%, and brain 4%. The most common treatment modality was surgery alone: 63.6% followed by surgery and adjuvant radiation: 33%. A few received chemotherapy (1.8%) or multimodality therapy (1.2%). The 5-year overall survival rate was 90.6% (95%CI 89.1-91.9), and disease-specific survival was 94.6% (95%CI 93.3-95.6). Multivariable cox regression analysis showed that undifferentiated (HR = 8.3) and poorly differentiated tumor grade (HR = 6.4), and metastasis (HR = 5.3) were the worst independent prognostic factors. Other poor risk factors included age > 50 (HR = 3.5) and tumor size > 4 cm (HR = 2.5).

CONCLUSIONS

In the US, AciCC is more common in middle age white females, and most tumors are less than 4 cm and localized at diagnosis. The most relevant negative prognostic factor was high tumor grade which was associated with higher hazard ratios for death than all other variables, including regional or distant metastases at presentation.

Secretory carcinoma in the parotid gland of a pediatric patient. A challenging diagnosis

Secretory carcinoma is a rare, recently identified and recognized neoplasm in major salivary glands. Few cases have been described with only 16 pediatric cases in the literature. We present a case preoperatively identified as a benign parotid lesion whose management was delayed due to the COVID-19 pandemic. Post enucleation of the lesion, histology identified a secretory carcinoma. This led to further and more extensive surgery to ensure complete removal. Clinicians and histopathologists should be aware of secretory carcinoma in their differential, as a high index of suspicion is required to ensure appropriate investigations are performed to obtain the diagnosis. Early identification is important to allow timely appropriate surgery to be performed.

Top Ten Oncocytic Head and Neck Lesions to Contemplate

BACKGROUND

Oncocytes are a component of many metaplastic and neoplastic lesions throughout the head and neck area, primarily originating in salivary/seromucinous glands and the thyroid gland. In addition, other lesions can contain cells that mimic oncocytes (pseudo-oncocytes); these can be of epithelial or non-epithelial origin.

METHODS

Review article.

RESULTS

Oncocytic metaplasia is common in seromucinous glands throughout the upper aerodigestive tract, most notable in the oral cavity, nasopharynx and larynx. The main oncocytic salivary gland neoplasms are Warthin tumor and oncocytoma. Infarction of Warthin tumor may lead to recognition difficulties. Oncocytic subtypes of mucoepidermoid carcinoma and intraductal carcinoma have morphologic and immunohistochemical features that allow distinction from major oncocytic entities. Oncocytic thyroid tumors include adenoma, carcinoma (follicular, papillary and medullary), along with poorly differentiated tumors. Oncocytic papillary sinonasal and middle ear tumors must be distinguished from low grade adenocarcinomas. Pseudo-oncocytic entities include paraganglioma, Langerhans cell histiocytosis, giant cell tumor, rhabdomyoma, and metastatic tumors.

CONCLUSIONS

Correct diagnosis of oncocytic head and neck lesions requires a knowledge of the spectrum of possible entities, their characteristic sites of occurrence, architecture, histomorphology, and immunohistochemistry. Oncocytic subtypes of several newly described entities are now recognized. Both epithelial and non-epithelial mimics of oncocytes exist. The molecular features of oncocytic tumors can be helpful in their diagnosis and understanding their pathogenesis.

Nodal Metastases in Pediatric and Adult Acinic Cell Carcinoma of the Major Salivary Glands

OBJECTIVE

Acinic cell carcinoma (AciCC) is a rare, usually low-grade salivary malignancy. Evidence on rates of lymph node metastases (LNMs) is limited in pediatric patients and varies significantly (4%-45%) in adults. We set out to determine and compare rates of LNMs in pediatric and adult AciCC and to analyze their impact on survival, using the National Cancer Database.

STUDY DESIGN

Historical cohort study.

SETTING

National Cancer Database.

METHODS

All AciCCs of the major salivary glands with complete clinical and pathologic nodal staging were selected between 2010 and 2016. Patient demographics, tumor characteristics, treatment, and survival were analyzed. Univariable and multivariable regression were performed to determine factors associated with LNMs and survival.

RESULTS

We identified 57 (4.6%) pediatric patients (<18 years) and 1192 (95.4%) adults with AciCC. Clinical LNMs were rare in pediatric patients (n < 10) and adults (n = 88, 7.4%). Occult LNMs were uncommon in pediatric patients (n < 5) and adults (n = 41, 4.6%). Three-year overall survival for pediatric patients was 97.8%. Adults with LNM had worse 3-year overall survival than those without (66.0% vs 96.3%, P < .001). In multivariable regression, high-grade disease (hazard ratio, 10.15 [95% CI, 5.60-18.80]; P < .001) and T3-T4 tumors (hazard ratio, 2.80 [95% CI, 1.56-4.97]; P < .001) were associated with LNM in adult patients.

CONCLUSION

LNMs in AciCC of the major salivary glands are rare in children and adults. However, high-grade and T3-T4 tumors are associated with an increased risk of LNM. LNM is associated with worse survival.

Secretory carcinoma of the sinonasal cavity and pharynx: A retrospective analysis of four cases and literature review

Secretory carcinoma (SC) is a recently recognized type of salivary gland tumor characterized by t(12;15) (p13;q25) translocation resulting in an ETV6-NTRK3 gene fusion. Most SCs are located in a main salivary gland, and primary sinonasal secretary carcinoma is rare. We describe three cases of primary SC in the sinonasal cavity with high-grade transformation (HGT) in one case, and the first case in the pharynx. All tumors comprised slightly atypical cells with solid, tubular, microcystic growth patterns. The case with HGT included two components with distinct sharp boundaries and comedo necrosis, high mitotic figures and obvious cellular atypia. Tumor cells were positive for vimentin, S100, and Gata-3 and negative for p63 and DOG-1. Three cases showed nuclear staining of pan-TRK and one showed cytoplasmic staining. All cases harbored ETV6 gene rearrangement, and ETV6-NTRK3 gene fusion was detected in three cases. Most patients were treated with radical resection and adjuvant therapy. After excision, all remained tumor-free for 65-164 months (medium 98.5 months). SC in the sinonasal cavity and pharynx is a low-grade malignant tumor with histologic features overlapping those of other salivary gland tumors. Immunohistochemical analysis and fluorescence in situ hybridization are useful techniques for its differential diagnosis.

Mammary analogue secretory carcinoma presenting with cervical lymphadenopathy: A rare case report with review of the literature

Introduction

Mammary analogue secretory carcinoma is a rare malignant tumor of the salivary glands that typically involves the major glands. The aim of the current study is to report a rare case of mammary analogue secretory carcinoma that presented with left cervical lymphadenopathy.

Case report

A 59-year-old lady presented with left cervical lymphadenopathy. Tissue biopsy and immunohistochemistry revealed metastatic carcinoma, favoring ovarian origin. Staging workup was performed and, ultimately, the patient was treated as having a carcinoma of unknown primary. After showing partial response to therapy, left side neck dissection was performed. Based on better assessment of the histologic picture and a broader panel of immunohistochemistry performed on the excision specimen, the final diagnosis was that of mammary analogue secretory carcinoma.

Discussion

Mammary analogue secretory carcinoma is usually an indolent salivary gland carcinoma, with the majority of patients presenting with a slow-growing, painless mass measuring approximately 2 cm in size, and a reported duration ranging from 2 months to several years. In certain cases, pain and facial paralysis have been reported. It could also be found incidentally during radiologic assessment for thyroid illness or routine dental screening.

Conclusion

Diagnosing mammary analogue secretory carcinoma is challenging, and this should be in the differential diagnosis list of metastatic carcinomas to cervical lymph nodes.

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Mammary analogue secretory carcinoma (MASC) is a rare malignant salivary gland neoplasm.

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MASC has similar histologic and molecular characteristics to breast secretory carcinoma.

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MASC was first reported in 2010 by Skalova et al.

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In this report, a brief review regarding this condition is discussed.

Identification of LMO2 as a new marker for acinic cell carcinoma of salivary gland

Background

The distinction between acinic cell carcinoma (ACC) and secretory carcinoma (SC) of the salivary gland is hampered by the lack of specific diagnostic markers. It is known the cytoplasm of glandular cells in the salivary gland immunohistochemically expresses LIM Domain Only 2 (LMO2). Herein, we aim to evaluate the expression status of LMO2 in a large cohort of tumors of the salivary gland, with an emphasis on its significance in the distinction of ACC and SC.

Methods

Immunohistochemical stains were performed to evaluate the expression of LMO2 in normal tissues and tumors of salivary gland.

Results

LMO2 was expressed in normal serous acinar cells of the salivary gland. We also found the cytoplasmic immunostaining of LMO2 was specific and sensitive for the recognition of ACCs including those with morphological overlaps with SCs, whereas the cytoplasmic expression of LMO2 was not detected in SCs.

Conclusions

LMO2 is useful for the recognition of ACC and is of potential value in distinguishing ACC from SC.

Clinicopathological investigation of secretory carcinoma cases including a successful treatment outcome using entrectinib for high-grade transformation: a case report

Background

Secretory carcinoma (SC) of the salivary gland is a recently described malignant tumor harboring characteristic ETV6-NTRK3 gene fusion. SC generally has a favorable clinical course, and is currently regarded as a low-grade carcinoma. However, a small subset of SCs demonstrates aggressive clinical features with histologically high-grade transformed morphology, the molecular pathogenesis of which has not yet been elucidated. In this study, we performed a clinicopathological and molecular genetic study of patients with SC of the head and neck displaying various clinical characteristics to investigate the differences of pathological and molecular genetics between low-grade and high-grade components of SC.

Case presentation

Three cases with SC of the head and neck, including a conventional low-grade SC and two high-grade transformed SCs are described. High-grade transformed SCs with histological features such as nuclear polymorphism, distinctive nucleoli and increased mitotic activity developed locoregional recurrence and distant metastasis. Immunohistochemical analysis revealed that low- and high-grade components showed different expression patterns for S-100 protein and mammaglobin, whereas all examined components were positive for p-STAT5. p53-positive cell population was markedly higher in one case with high-grade transformed SC. The proliferative activity of high-grade components was markedly increased, with the Ki-67 labeling index ranging up to 30–32%. A fluorescence in situ hybridization study with an ETV6 (12p13) break apart probe revealed split signals in the nuclei in all 3 cases. A targeted next-generation sequencing-based fusion assay demonstrated that all 6 clinical samples from the 3 patients showed the presence of the ETV6-NTRK3 fusion transcripts. One patient with high-grade transformed SC showed a dramatic clinical response to the pan-TRK inhibitor, entrectinib, for the treatment of locoregional recurrence and pulmonary metastasis.

Conclusions

High-grade transformed SC showed aggressive clinical and pathological features with increased Ki-67 labeling index. Molecular genetic study of gene rearrangement appears to be beneficial treatment as the presence of ETV6-NTRK3 translocation may represent a therapeutic target in SC, particularly the high-grade transformed type.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-022-01155-6.

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.

Fusion-Positive Salivary Gland Carcinomas

Salivary gland tumors are a rare, heterogeneous group of neoplasms that pose significant diagnostic challenges for the histopathologist. Histopathological diagnosis relies primarily on morphological assessment, with ancillary special stains and immunohistochemistry. In recent years, new defining genomic alterations have been characterized in these tumors. In particular, they include gene fusions which have shown to be tightly tumor-type specific, and thus valuable for use in diagnostically challenging cases. These discoveries also help in refining tumor classification. Furthermore, such genetic alterations may have prognostic as well as potentially therapeutic implications in the era of personalized medicine. This review aims at providing a summary of the most recent updates in this field.

Mammary analogue secretory carcinoma of a salivary gland of the hard palate with contralateral cervical lymph node metastases: A case report

Mammary analogue secretory carcinoma (MASC) is a rare malignant tumour of the salivary glands, with only few cases reported in the literature to date. Initial preoperative staging is crucial for all patients with an oral malignancy to visualize the tumour, detect lymph node or distant metastases and plan therapeutic interventions. In the case presented herein, radiological imaging revealed a tumour of the right hard palate with suspected positive contralateral lymph nodes. Therefore, local tumour resection comprising hemimaxillectomy and bilateral neck dissection was performed. The diagnosis of MASC was finally based on characteristic histopathological and immunohistochemical findings, such as S100 protein and mammaglobin positivity. The diagnosis of MASC may be challenging, as such findings lack specificity. To confirm the diagnosis, molecular genetic examinations may be performed to detect a highly specific ETV6-NTRK3 fusion gene. Depending on the results of these examinations, surgery, alone or combined with adjuvant radiation or chemoradiation, is the recommended approach. In summary, MASC should be treated similarly to other low-grade salivary gland tumours, such as acinic cell carcinoma, as they exhibit biological and histopathological similarities.

Intraductal carcinoma of the salivary gland with NCOA4-RET: expanding the morphologic spectrum and an algorithmic diagnostic approach

After the publication of the 2017 World Health Organization Classification of Head and Neck Tumours, there has been increasing interest in the classification of newly categorized intraductal carcinomas. Intraductal carcinoma (IC) is an indolent tumor, typically arising in the parotid gland, with an intact myoepithelial layer and a cystic, papillary, often cribriform architecture. Early studies of IC identified a heterogeneous group of molecular alterations driving neoplasia, and recent studies have defined three primary morphological/immunohistochemical variants, subsequently linking these morphologic variants with defined molecular signatures. Although studies to date have pointed toward distinct molecular alterations after histological classification, this study used a novel approach, focusing primarily on six cases of IC with NCOA4-RET gene rearrangement as determined by next-generation sequencing and describing the spectrum of clinicopathologic findings within that molecularly-defined group, among them a unique association between the NCOA4-RET fusion and hybrid variant IC and the first case of IC arising in association with a pleomorphic adenoma. RET-rearranged IC show histological and immunohistochemical overlap with the more widely recognized secretory carcinoma, including low-grade morphology, a lumen-forming or microcystic growth pattern, and co-expression of S100, SOX10, and mammaglobin, findings undoubtedly leading to misdiagnosis. Typically regarded to have ETV6-NTRK3 fusions, secretory carcinomas may alternatively arise with RET fusions as well. Adding our cohort of six NCOA4-RET fusion-positive IC compared with four cases of secretory carcinoma with ETV6-RET fusions and a single case of fusion-negative IC with salivary duct carcinoma-like genetics, we propose a diagnostic algorithm that integrates histological elements, including atypia and invasiveness, and the likelihood of specific molecular alterations to increase diagnostic accuracy in what can be a very subtle diagnosis with important clinical implications.

Oncocytic intraductal carcinoma of salivary glands: a distinct variant with TRIM33-RET fusions and BRAF V600E mutations

AIMS

Salivary gland intraductal carcinoma (IDC) is a complex ductal neoplasm surrounded by a layer of myoepithelial cells. Recent insights have shown that there are three different types: intercalated duct-like, with frequent NCOA4-RET fusions; apocrine, with salivary duct carcinoma-like mutations; and mixed intercalated duct-like/apocrine, with RET fusions, including TRIM27-RET. In addition, an oncocytic IDC has been described, but it remains unclear whether it represents a fourth variant or simply oncocytic metaplasia of another IDC type. Our aim was to more completely characterize oncocytic IDC.

METHODS AND RESULTS

Six IDCs with oncocytic changes were retrieved from the authors' archives, from three men and three women ranging in age from 45 to 75 years (mean, 63 years). Five arose in the parotid gland, with one in an accessory parotid gland. Four patients with follow-up were free of disease after 1-23 months. Several immunostains (S100, mammaglobin, androgen receptor, and p63/p40) and molecular tools (RNA sequencing, RET fluorescence in-situ hybridisation, BRAF V600E VE1 immunohistochemistry, and Sanger sequencing) were applied. Histologically, the tumours were variably cystic with solid intracystic nodules often difficult to recognise as intraductal. In all, tumour ducts were positive for S100 and mammaglobin, negative for androgen receptor, and completely surrounded by myoepithelial cells positive for p63/p40. Molecular analysis revealed TRIM33-RET in two of six cases, NCOA4-RET in one of six cases, and BRAF V600E in two of six cases. One case had no identifiable alterations.

CONCLUSIONS

Oncocytic IDC shares similarities with intercalated duct-like IDC. Although additional verification is needed, the oncocytic variant appears to be sufficiently unique to be now regarded as the fourth distinct subtype of IDC. Because of its indolent nature, oncocytic IDC should be distinguished from histological mimics.

A case report of surgical resection of secretory carcinoma in the maxillary and ethmoid sinus

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Mammary Analogue Secretory Carcinoma (MASC) is a head and neck tumour that was first defined in 2010.

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Only two cases of Secretory Carcinoma have reported in the sinuses.

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We present a case of a Secretory Carcinoma presenting in the maxillary and ethmoid sinuses.

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The tumour treated with surgical resection and re-resection and was disease free at 1 year follow up.

Introduction

Secretory Carcinoma is a recently discovered head and neck tumour. Surgical resection is generally the first line of treatment with neck dissection, radiation, and chemotherapy decided based on clinical, radiological, and histological parameters. We present a case of a Secretory Carcinoma presenting in the maxillary and ethmoid sinuses.

Case

A 39-year-old male presented with left nasal obstruction and chronic rhinosinusitis beginning after surgical repair of the mandible and maxilla due to facial trauma. A CT scan of the head showed soft tissue density in the left maxillary sinus extending through the ethmoid sinus and posterior nasal cavity. Functional endoscopic sinus surgery (FESS) was performed to remove the obstructing lesion. Biopsy was analysed and the main differential diagnosis was between a non-intestinal type adenocarcinoma of nasal origin and a salivary carcinoma.

Discussion

To our knowledge, there have only been two cases of Secretory Carcinoma reported in the sinuses: one case in the ethmoid sinus and the other in the maxillary sinus. This is the first to report follow up at 1 year.

Conclusion

Both MRI and exam showed no evidence of recurrent disease at one year follow up. This report aims to further the understanding of Secretory Carcinoma tumours in the sinuses. Our report could be used to further understand diagnostic criteria for Secretory Carcinoma in the sinuses as well as treatment outcomes for surgical resection without adjuvant treatment.

Expanding the Molecular Spectrum of Secretory Carcinoma of Salivary Glands With a Novel VIM-RET Fusion

BACKGROUND

Secretory carcinoma (SC), originally described as mammary analogue SC, is a predominantly low-grade salivary gland neoplasm characterized by a recurrent t(12;15)(p13;q25) translocation, resulting in ETV6-NTRK3 gene fusion. Recently, alternative ETV6-RET, ETV6-MAML3, and ETV6-MET fusions have been found in a subset of SCs lacking the classic ETV6-NTRK3 fusion transcript, but still harboring ETV6 gene rearrangements.

DESIGN

Forty-nine cases of SC revealing typical histomorphology and immunoprofile were analyzed by next-generation sequencing using the FusionPlex Solid Tumor kit (ArcherDX). All 49 cases of SC were also tested for ETV6, RET, and NTRK3 break by fluorescence in situ hybridization and for the common ETV6-NTRK3 fusions using reverse transcription polymerase chain reaction.

RESULTS

Of the 49 cases studied, 37 (76%) occurred in the parotid gland, 7 (14%) in the submandibular gland, 2 (4%) in the minor salivary glands, and 1 (2%) each in the nasal mucosa, facial skin, and thyroid gland. SCs were diagnosed more frequently in males (27/49 cases; 55%). Patients' age at diagnosis varied from 15 to 80 years, with a mean age of 49.9 years. By molecular analysis, 40 cases (82%) presented the classic ETV6-NTRK3 fusion, whereas 9 cases (18%) revealed an alternate fusion. Of the 9 cases negative for the ETV6-NTRK3 fusion, 8 cases presented with ETV6-RET fusion. In the 1 remaining case in the parotid gland, next-generation sequencing analysis identified a novel VIM-RET fusion transcript. In addition, the analysis indicated that 1 recurrent high-grade case in the submandibular gland was positive for both ETV6-NTRK3 and MYB-SMR3B fusion transcripts.

CONCLUSIONS

A novel finding in our study was the discovery of a VIM-RET fusion in 1 patient with SC of the parotid gland who could possibly benefit from RET-targeted therapy. In addition, 1 recurrent high-grade case was shown to harbor 2 different fusions, namely, ETV6-NTRK3 and MYB-SMR3B. The expanded molecular spectrum provides a novel insight into SC oncogenesis and carries important implications for molecular diagnostics, as this is the first SC-associated translocation with a non-ETV6 5' fusion partner. This finding further expands the definition of SC while carrying implications for selecting the appropriate targeted therapy.

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.

A case of secretory carcinoma of the submandibular gland with unusual immunohistochemical staining

Mammaglobin negative secretory carcinoma may be overlooked. It is important to assess the possibility of diagnosis when histology is suggestive and immunohistochemical staining for S-100 is positive even when staining for mammaglobin is negative.

Secretory carcinoma of salivary type in a lymph node presenting as a neck cyst diagnosed by cytology: A case report

Secretory carcinoma (SC) is a relatively recently described salivary gland adenocarcinoma characterized by ETV6-NTRK3 gene fusion and, in most cases, indolent clinical behavior. Morphologically, the tumor shows a glandular architecture and the presence of monophasic tumor cells with vacuolated cytoplasm, low-grade nuclear atypia, and mucin production, with possibly a tubular, papillary, or cystic arrangement. In this article, we describe a case of a 52-year old man with SC involving a neck lymph node clinically manifesting as a slowly growing cystic neck mass without recent proof of the primary tumor, but with a history of a parotid gland "cystadenopapilloma," which had been removed 35 years prior. A fine-needle aspiration biopsy revealed a diagnosis of SC. Subsequent histopathological examination after lymph node dissection confirmed the diagnosis. The tumor showed typical features of SC, including immunohistochemical positivity for NTRK and NTRK3 gene rearrangement, detected using in situ hybridization. We discuss that the tumor may be a late metastasis occurring 35 years after resection of undiagnosed salivary SC or a primary SC arising from heterotopic salivary tissue within a lymph node. Differential diagnostic considerations and review of relevant literature are included.

Head and Neck Cancers, Version 2.2020, NCCN Clinical Practice Guidelines in Oncology

Treatment is complex for patients with head and neck (H&N) cancers with specific site of disease, stage, and pathologic findings guiding treatment decision-making. Treatment planning for H&N cancers involves a multidisciplinary team of experts. This article describes supportive care recommendations in the NCCN Guidelines for Head and Neck Cancers, as well as the rationale supporting a new section on imaging recommendations for patients with H&N cancers. This article also describes updates to treatment recommendations for patients with very advanced H&N cancers and salivary gland tumors, specifically systemic therapy recommendations.

Expression of upstream and downstream targets of mTOR pathway in seven cases of secretory carcinoma of salivary gland origin

PURPOSE

To investigate the expression of upstream and downstream targets of mTOR signalling pathway in the secretory carcinoma of salivary gland origin (SCsg).

METHODS

Seven cases of secretory carcinoma diagnosed by a combination of immunohistochemistry and/or molecular testing were retrieved from our pathology files. For comparison purposes, 27 other salivary carcinomas were selected. Immunohistochemical staining was performed against phospho-Akt, PTEN, phospho-mTOR, phospho-4E-BP, eIF4E and phospho-S6 ribosomal protein.

RESULTS

With the exception of Akt, all the other proteins were present at some level in the SCsg and in other salivary carcinomas. PTEN was diffusely expressed in 57.1% of SCsg, but only in 14.8% of other salivary carcinomas. mTOR is expressed in more than half of the cases both for SCsg and other salivary tumour types. Most cases of SCsg showed negative expression for S6 ribosomal protein (71.4%) and 4E-BP1 (57.1%). For both groups evaluated, eIF4E was the most expressed protein.

CONCLUSION

SCsg shows different expression patterns for the mTOR signalling molecules, but only eIF4E was highly expressed. This may suggest alternative signalling pathways other than Akt and mTOR in this group of tumours.

Retrospective Study of Buccal Mucosal Salivary Neoplasms

Salivary gland neoplasms of the buccal mucosa are relatively rare and often present with an unusual histopathologic profile when compared with other intraoral locations. We present a series of minor salivary gland neoplasms of the buccal mucosa and discuss demographics, clinical presentation, and histologic findings. An IRB approved retrospective search of University of Florida Oral Pathology Biopsy Service archive from 1994 to 2018 for all salivary gland neoplasms of the buccal mucosa was undertaken. Data related to age, gender, clinical presentation, diagnosis, and category of neoplasm recorded. Review for consensus of diagnosis and immunohistochemical (IHC) testing on current diagnostic standards was performed and diagnoses updated based on results. Of 66 cases identified majority were females (72.7%) and age mean was 63 years. Benign tumors were 56.06% and 43.94% malignant, with Mucoepidermoid carcinoma (MEC) being commonest (26/66, 39.4%), followed by canalicular adenoma (CLA) (14/66, 21.2%), ductal papilloma (DP) (10/66, 15.2%), cystadenoma (CA) (8/66, 12.1%), basal cell adenoma (BCA) (4/66, 6.1%), and 1(1.5%) each for pleomorphic adenoma (PA), secretory carcinoma (SC), adenoid cystic carcinoma (ACC) and adenocarcinoma not otherwise specified (ACNOS). This study with respect to demographics and percentage of benign and malignant buccal mucosal salivary gland neoplasms is in conformity with the literature. It underscores the fact that both benign and malignant salivary gland neoplasms should be included in the differential diagnosis of submucosal buccal masses. Future larger multicenter studies with detailed treatment and outcomes data may aid and assist in further understanding the behavior, diverse histomorphology and prognosis of these neoplasms.

Usefulness of immunohistochemistry to distinguish between secretory carcinoma and acinic cell carcinoma in the salivary gland

Secretory carcinoma (SC) of the salivary gland is a relatively newly described disease, separate from acinic cell carcinoma (ACC), which frequently displays ETV6-NTRK3 gene fusion. However, the differences between SC and ACC remain unclear. Here, histological reevaluation of 12 formerly diagnosed ACC cases was performed, which yielded a new diagnosis of SC in four cases due to a lack of obvious acinar-like cells. Immunohistochemically, phosphorylated signal transducer and activator of transcription 5 (p-STAT5) was expressed in SC but not in ACC, whereas discovered on GIST-1 (DOG1) was expressed in ACC but not in SC. Molecular analysis was possible in three SC cases, of which two showed the ETV6-NTRK3 fusion transcript on reverse-transcription polymerase chain reaction, as well as breaks in the ETV6 gene on fluorescence in situ hybridization. However, the remaining SC cases did not show this fusion transcript. Recently, several reports have suggested that SC might not be adequately diagnosed if the focus is placed solely on the ETV6-NTRK3 fusion gene due to genetic diversity. In this regard, immunohistochemistry of p-STAT5 and DOG1 is expected to be a useful alternative diagnostic tool to discriminate SC from ACC.

Major and minor salivary gland tumours

Salivary glands carcinomas are very rare epithelial malignant tumors. In 2013 in Europe, 7800 new diagnoses were estimated, 8.5 % of all head and neck cancer. The last WHO classification (2017) counts more than 20 malignant histotypes, this variety as well as the rarity of some of them needs a skilled pathologist for diagnosis. Surgery remains the mainstay of management followed by radiation in high-grade and high-risk pathological features cases. The intensity modulated radiotherapy (IMRT) should be preferred over conformational radiotherapy techniques as adjuvant and exclusive treatment in advanced cases. Particle radiotherapy (i.e. protons, carbon ions) can have a role in advanced/unresectable disease since it was proved to have better results over photons in loco-regional control both in adenoid cystic carcinoma and in other histotypes. Although chemotherapy is still the most frequent treatment for metastatic patients, several new compounds (i.e. anti-angiogenic agents, tailored agents, checkpoint inhibitors) are under investigation.

Primary Mammary-Analogue Secretory Carcinoma of the Lung: A Rare Entity With an Unusual Location

This is a case of a 55-year-old female with past medical history of tobacco smoking, hypertension, and lupus who presented with a left lung nodule, found on computed tomographic scan of the chest during workup for a recently diagnosed squamous cell carcinoma in a cervical lymph node. Resection of the lung nodule showed a 2.3-cm well-defined pale-tan mass, and histologic examination showed a well-circumscribed lesion with papillary, solid, and gland-like architectural patterns, with eosinophilic secretions, areas of comedonecrosis, and increased mitotic activity. Immunohistochemical stains showed the lesion to be positive for cytokeratin 7, S100 protein, and focally positive for mammaglobin. Fluorescence in situ hybridization studies confirmed rearrangement of the ETV6 gene at 12p13.2. To date, our case is the second reported case of a primary mammary-analogue secretory carcinoma arising in the lung, and the first to show evidence of tumor necrosis: an unusual feature in an unusual location.

Secretory Carcinoma of Salivary Gland with High-Grade Histology Arising in Hard Palate: A Case Report

Secretory carcinoma (SC) is a recently described salivary gland tumor reported in the fourth edition of World Health Organization classification of head and neck tumors. SC is characterized by strong S-100 protein, mammaglobin, and vimentin immunoexpression, and harbors a t(12;15)(p13;q25) translocation which leads to ETV6-NTRK3 fusion product. Histologically, SC displays a lobulated growth pattern and is often composed of microcystic, tubular, and solid structures with abundant eosinophilic homogenous or bubbly secretion. SC is generally recognized as low-grade malignancy with low-grade histopathologic features, and metastasis is relatively uncommon. In this case, we described a SC of hard palate that underwent high grade transformation and metastasis to the cervical lymph node in a 54-year-old patient. In addition, this case showed different histological findings between primary lesion and metastasis lesion. Therefore, the diagnosis was confirmed by the presence of ETV6 translocation. Here, we report a case that occurred SC with high-grade transformation in the palate, and a review of the relevant literature is also presented.

A Challenging Case of Mammary Analogue Secretory Carcinoma: Case Study with Ultrastructural and Cytogenetic Correlation

Mammary analogue secretory carcinoma (MASC) is a rare salivary gland tumor analogous to secretory carcinoma of the breast. The diagnosis of MASC can be challenging due to substantial morphologic and immunohistochemical similarities with other salivary gland tumors. The differential diagnosis of MASC is broad and includes intraductal carcinoma, acinic cell carcinoma, and adenocarcinoma, not otherwise specified. Although molecular testing for ETV6 gene rearrangement is characteristic of MASC and has not been shown in any other salivary gland tumor, a particular challenge arises when such testing is unavailable, or when molecular testing for ETV6 gene rearrangement is negative in a suspected case of MASC. Our study presents the diagnostic workup of a challenging case of MASC with immunohistochemistry, electron microscopy, and cytogenetic studies performed to resolve the diagnosis.

Pan-Trk immunohistochemistry is a sensitive and specific ancillary tool for diagnosing secretory carcinoma of the salivary gland and detecting ETV6-NTRK3 fusion

AIMS

Secretory carcinoma (SC) of the salivary gland typically harbours ETV6-NTRK3 fusion, which can be utilised clinically to assist with diagnosis. Pan-Trk inhibitor therapy has demonstrated drastic responses in patients with NTRK-translocated tumours, including SC. Pan-Trk immunohistochemistry (IHC) is emerging as a sensitive and specific tool for detecting NTRK1, NTRK2 and NTRK3 fusions in various cancers. We aimed to establish the specificity and sensitivity of pan-Trk IHC in diagnosing SC and detecting ETV6-NTRK3 fusion. A literature review on the utility of pan-Trk IHC was conducted.

METHODS AND RESULTS

Pan-Trk IHC was performed on 83 salivary gland neoplasms (29 SCs and 54 non-SCs). ETV6-NTRK3 fusion status was established in 25 cases. With any staining (nuclear or cytoplasmic) as a positive threshold, the sensitivity and specificity of pan-Trk IHC were 90% and 70% in diagnosing SC, and 100% and 0% in detecting NTRK3 fusion. When only pan-Trk nuclear staining was considered as positive, the sensitivity and specificity were 69% and 100% in diagnosing SC, and 92% and 100% in detecting NTRK3 fusion.

CONCLUSIONS

Nuclear pan-Trk IHC is highly specific for SC diagnosis, with a specificity approaching 100%, making it a useful and precise diagnostic tool for differentiating SC from its histological mimics. On the other hand, any pan-Trk staining (nuclear or cytoplasmic) is highly sensitive for SC, and can serve as an attractive, cheap, fast and accessible screening tool for selecting patients to undergo confirmative molecular testing for clinical trials using TRK inhibitors.

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.

Primary Mammary Analog Secretory Carcinoma (MASC) of the Vulva With ETV6-NTRK3 Fusion: A Case Report

Mammary analog secretory carcinoma is a primary salivary gland neoplasm with histologic, immunophenotypic, and molecular features identical to those of secretory carcinoma of the breast. Similar neoplasms have now been reported to occur in various nonmammary sites including the parotid gland, submandibular gland, sinuses, lip, skin, thyroid gland, and lung. We report, to our knowledge, the first example of a primary vulvar neoplasm with pathologic features identical to secretory carcinoma of the breast and an ETV6-NTRK3 fusion.

Mammary Analog Secretory Carcinoma of the Nasal Cavity: Characterization of 2 Cases and Their Distinction From Other Low-grade Sinonasal Adenocarcinomas

Secretory carcinoma, originally described as mammary analog secretory carcinoma (MASC), is a low-grade salivary gland tumor characterized by a t(12;15)(p13;q25) translocation, resulting in an ETV6-NTRK3 gene fusion. Most MASCs are localized to the parotid gland and intraoral minor salivary glands. Moreover, ETV6-rearranged carcinomas with secretory features have been reported recently in the thyroid (with and without a history of radiation exposure), skin, and in very rare instances in the sinonasal tract. Here, we describe 2 cases of primary MASC in the sinonasal tract and provide a detailed clinical and histopathologic characterization of their morphology, immunohistochemical profile, and genetic background and highlight features allowing for its separation from its recently described molecular mimicker, ETV6-rearranged low-grade sinonasal adenocarcinoma.

Mammary Analogue Secretory Carcinoma of the Palate: Case Report and Review of the Literature

Mammary analogue secretory carcinoma (MASC) is a recently described salivary gland tumor, with a limited number of published reports. Less than three hundred cases have been reported in the literature and only 18 of these cases have been reported in minor palatal salivary glands, though publication bias is likely a factor. We present a case of a 57-year-old male who was diagnosed with MASC tumor presenting in a minor salivary gland and briefly review the current literature. MASC has a variety of histological features and different range of clinical behaviors. The histopathological diagnosis of MASC can be difficult, and the immunohistochemical profile of MASC is still being updated. The gold standard for MASC diagnosis is cytogenetics, with the majority having a translocation t(12;15)(p133;q25). Presently, there is no conclusive evidence that MASC should be treated differently than any other low-grade malignant salivary gland tumors, though high-grade transformation has been described.

Novel gene fusions in secretory carcinoma of the salivary glands: enlarging the ETV6 family

Secretory carcinoma (SC) of the salivary gland is a low-grade malignancy associated with a well-defined clinical, histologic, immunohistochemical, and cytogenetic signature. Although the t(12;15) (p13;q25) translocation resulting in an ETV6-NTRK3 gene fusion is well documented, advances in molecular profiling in salivary gland tumors have led to the discovery of RET as another ETV6 gene fusion partner in SC. Here, we applied an RNA-based next-generation sequencing (NGS) approach for fusion detection on 14 presumed SC. The cases included 7 SC with classic ETV6-NTRK3 gene fusion and 3 SC harboring ETV6-RET gene fusion. In addition, 2 cases revealed a NCOA4-RET gene fusion and were subsequently reclassified as intraductal carcinomas. One case with an unusual dual-pattern morphology revealed a novel translocation involving ETV6, NTRK3, and MAML3 gene rearrangements. Interestingly, no ETV6-NTRK3 or ETV6-RET SC was ever documented to have this unique dual-pattern morphology or harbor a MAML3 mutation. The remaining case had no detected chromosomal abnormalities. Advances in molecular profiling of SC have led to the discovery of novel fusion partners such as RET and now MAML3. Further molecular characterization of salivary gland neoplasms is needed as these mutations may present alternative therapeutic targets in patients with these tumors.