The profile of acinic cell carcinoma after recognition of mammary analog secretory carcinoma

ETV6 Molecular Heterogeneity in Salivary Secretory Carcinoma: A Case Series Report and Literature Review

BACKGROUND

ETV6 gene rearrangement is the molecular hallmark of secretory carcinoma (SC), however; the nature, frequency, and clinical implications of atypical ETV6 signal patterns by fluorescence in situ hybridization (FISH) has not yet been systematically evaluated in salivary gland neoplasms.

METHODS

The clinical, histopathologic, immunohistochemical and molecular features of seven salivary SCs, including four cases with atypical ETV6 FISH patterns, were retrospectively analyzed along with a critical appraisal of the literature on unbalanced ETV6 break-apart in SCs.

RESULTS

The patients were four males and three females (31-70 years-old). Five presented with a painless neck mass and two patients with recurrent disease had a history of a previously diagnosed acinic cell carcinoma of the buccal mucosa. Histologically, there were varied combinations of microcystic, papillary, tubular, and solid patterns. All tumors were diffusely positive for S100 and/or SOX10, while 2 cases also showed luminal DOG1 staining. Rearrangement of the ETV6 locus was confirmed in 5/7 cases, of which 3 cases showed classic break-apart signals, 1 case further demonstrated duplication of the ETV6 5`end and the other loss of one copy of ETV6. Two cases harbored ETV6 deletion without rearrangement. Two of the 4 cases with atypical ETV6 FISH patterns represented recurrent tumors, one with widespread skeletal muscle involvement, bone and lymphovascular invasion. Surgical treatment resulted in gross-total resection in all 7 cases, with a median follow up of 9.5 months post-surgery for primary (n = 3) and recurrent disease (n = 1).

CONCLUSION

Duplication of the distal/telomeric ETV6 probe represented the most common (26/40; 65%) variant ETV6 break-apart FISH pattern in salivary SC reported in the literature and appears indicative of an aggressive clinical course.

PON3::LCN1 and HTN3::MSANTD3 Gene Fusions With NR4A3/NR4A2 Expression in Salivary Acinic Cell Carcinoma

Acinic cell carcinoma of the salivary gland (AciCC) is a low-grade carcinoma characterized by the overexpression of the transcription factor nuclear receptor subfamily 4 group A member 3 (NR4A3). AciCC has been the subject of a few molecular research projects. This study delves into AciCC's molecular landscape to identify additional alterations and explore their clinical implications. RNA sequencing and immunohistochemical staining for markers NR4A3/NR4A2, DOG-1, S100, and mammaglobin were utilized on 41 AciCCs and 11 secretory carcinoma (SC) samples. NR4A3 was evident in 35 AciCCs, while the residual 6 were NR4A3-negative and NR4A2-positive; SC samples were consistently NR4A3-negative. A novel fusion, PON3 exon 1- LCN1 exon 5, was detected in 9/41 (21.9%) AciCCs, exhibiting a classical histologic pattern with serous cell components growing in solid sheets alongside the intercalated duct-like component. Clinical follow-up of 39 patients over a median of 59 months revealed diverse prognostic outcomes: 34 patients exhibited no disease evidence, whereas the remaining 5 experienced poorer prognosis, involving local recurrence, lymph node, and distant metastasis, and disease-associated death, 4 of which harbored the PON3::LCN1 fusion. In addition, the HTN3::MSANTD3 fusion was recurrently identified in 7/41 AciCC cases. SC patients lacked both fusions. Immunohistochemistry uncovered differential expression of DOG-1, S100, and mammaglobin across samples, providing nuanced insights into their roles in AciCC. This study accentuates PON3::LCN1 and HTN3::MSANTD3 fusions as recurrent molecular events in AciCC, offering potential diagnostic and prognostic utility and propelling further research into targeted therapeutic strategies.

Acinic cell Carcinoma with high-grade Squamoglandular and Chondrosarcomatous Transformation Mimicking 'Carcinosarcoma ex-pleomorphic Adenoma': A Wrinkle in the Proposed Nomenclature Revision for Sarcomatoid Salivary Gland Neoplasms

While acinic cell carcinoma (AciCC) can undergo high-grade transformation (HGT) to high-grade adenocarcinoma or poorly differentiated carcinoma, other morphologies such as spindle cell/sarcomatoid carcinoma are rare and not well-characterized. We herein report a novel case of AciCC with squamoglandular and chondrosarcomatous HGT mimicking a so-called 'carcinosarcoma ex-pleomorphic adenoma'. The patient is an 81-year-old male with a two-month history of neck swelling and referred otalgia who presented with a left parapharyngeal space mass extending into retropharyngeal space and pterygoid muscles. On resection, the tumor showed considerable morphologic diversity with high-grade serous and mucous acinar components as well as cribriform to solid apocrine-like components with comedonecrosis and squamous differentiation, all of which were embedded in a chondromyxoid background ranging from paucicellular and bland to a high-grade chondrosarcoma/pleomorphic sarcoma-like appearance. Only a minor conventional AciCC component was noted. Immunostains were negative for AR and only focally positive for GCDFP-15 arguing against a true apocrine phenotype, while PLAG1 and HMGA2 were negative arguing against an antecedent pleomorphic adenoma. On the other hand, SOX-10, DOG-1 and PAS after diastase highlighted serous acinar differentiation, and mucicarmine, and NKX3.1 highlighted mucous acinar differentiation. NR4A3 immunohistochemical staining and NR4A3 fluorescence in situ hybridization were positive in the carcinomatous and sarcomatoid components while sequencing analysis of both components revealed identical alterations involving TP53, PIK3CB, ARID1A, and STK11. This unique case warrants caution in designating all salivary sarcomatoid carcinomas with heterologous elements as part of the 'carcinoma ex-pleomorphic adenoma' family.

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.

Diagnostic Utility of Expression Pattern of S100/Mammaglobin/SOX10/DOG 1 Immunohistochemistry in Differentiation of Secretory and Acinic Cell Carcinoma: A Systematic Review and Meta-Analysis

Secretory carcinoma (SC) is a relatively new disease entity, separate from acinic cell carcinoma (AciCC), which frequently displays ETV6-NTRK3 gene fusion. However, the differences between SC and AciCC remain ambiguous. Genetic diversity makes its diagnosis complicated. In this regard combined expression of immunohistochemistry markers S100/Mammaglobin/SOX10 and DOG1 is need of the hour as alternative methodology. The current systematic review was to investigate the diagnostic utility of combined immunohistochemical expression of S100/Mammaglobin/SOX10/DOG1 in distinction of SC from AciCC histologically. An electronic search of databases was carried out using MEDLINE by PubMed, Google scholar, Scopus and Web of science. Articles inclusive of SC and AciCC were assessed with S100/Mammaglobin/SOX10/DOG1 immunohistochemistry and their predominant expression pattern, predictive values, sensitivity and specificity were gathered. Fourteen eligible articles were analysed, which revealed predominant immunostaining pattern of S100 + /Mammaglobin + /SOX10 + /DOG1- by nearly all ETV6::NTRK3 fusion prevalent SCs alongside with other gene fusions like RET, MET and MAML3 with 98.4% sensitivity as well as 86.1% specificity. The evidence supports that S100/Mammaglobin/SOX10/DOG1 combined immunostaining can serve as a reliable diagnostic method to differentiate secretory from acinic cell carcinoma.

A Retrospective Multicenter Italian Analysis of Epidemiological, Clinical and Histopathological Features in a Sample of Patients with Acinic Cell Carcinoma of the Parotid Gland

BACKGROUND

The acinic cell carcinoma (AciCC) of the parotid gland is a rare tumor with an indolent behavior; however, a subgroup of this tumor presents an aggressive behavior with a tendency to recur. The aim of this multicenter study was to identify and stratify those patients with AciCC at high risk of tumor recurrence.

METHODS

A retrospective study was carried out involving 77 patients treated with surgery between January 2000 and September 2022, in different Italian referral centers. Data about tumor characteristics and its recurrence were collected. The histological specimens and slides were independently reviewed by a senior pathologist coordinator (L.C.) and the institution's local head and neck pathologist.

RESULTS

The patients' age average was 53.6 years, with a female prevalence in the group. The mean follow-up was 67.4 months (1-258, SD 59.39). The five-year overall survival (OS) was 83.2%. The 5-year disease-free survival (DFS) was 60% (95% CI 58.2-61.7). A high incidence of necrosis, extraglandular spread, lymphovascular invasion (LVI), atypical mitosis, and cellular pleomorphism was observed in the high-risk tumors compared to the low-risk ones.

CONCLUSION

AciCC generally had an indolent behavior, optimal OS, DFS with few cervical node metastases, and rare distant relapses. This multicenter retrospective case series provides evidence of the need for clinical-epidemiological-histological stratification for patients at risk of poor outcomes. Our results suggest that the correct definition of high-risk AciCC should include tumor size, the presence of necrosis, extraglandular spread, LVI, atypical mitosis, and cellular pleomorphism.

Case Report: A case of complete response to entrectinib in NTRK fusion gene-positive parotid gland cancer

Introduction

Expression of the NTRK gene is rare in solid tumors but is highly prevalent in salivary gland secretory carcinomas. Here, we report a case of a complete response to entrectinib in a patient with NTRK fusion gene-positive parotid carcinoma.

Case description

The patient was a 44-year-old man who underwent total left parotidectomy and left cervical lymph node dissection for a left parotid tumor at 24 years of age. The histopathological diagnosis was mammary analog secretory carcinoma. Postoperatively, the patient received only radiation therapy. Sixteen years after the surgery, the patient became aware of a mass in the left parotid region. A close examination revealed local recurrence and multiple cervical lymph node metastases. S-1 monotherapy was started as chemotherapy but was discontinued 3 years later because of disease progression. As there was no standard treatment, a comprehensive genomic profiling test using a next-generation sequencer was performed, and the ETV6-NTRK3 fusion gene was identified. Entrectinib, an NTRK inhibitor, was immediately administered at a dose of 600 mg/day. The local recurrence rapidly shrank grossly from the beginning of treatment, and a complete response was observed 6 months later. However, creatinine levels exhibited an increase at week 68 of treatment; consequently, entrectinib dosage was lowered to 400 mg/day, leading to an immediate improvement in creatinine levels. Entrectinib was associated with additional side effects, including dysgeusia, fatigue, dizziness, and weight gain, all of which were also alleviated by the reduction in entrectinib dose. Thirty months after treatment initiation, the patient maintained a complete response and continued to receive entrectinib.

Conclusion

The NTRK fusion gene should always be checked in the presence of salivary gland secretory carcinoma.

Salivary Gland Secretory Carcinoma: Clinicopathologic and Genetic Characteristics of 215 Cases and Proposal for a Grading System

Salivary gland secretory carcinoma (SC), previously mammary analog SC, is a low-grade malignancy characterized by well-defined morphology and an immunohistochemical and genetic profile identical to SC of the breast. Translocation t(12;15)(p13;q25) resulting in the ETV6 :: NTRK3 gene fusion is a characteristic feature of SC along with S100 protein and mammaglobin immunopositivity. The spectrum of genetic alterations for SC continues to evolve. The aim of this retrospective study was to collect data of salivary gland SCs and to correlate their histologic, immunohistochemical, and molecular genetic data with clinical behavior and long-term follow-up. In this large retrospective study, we aimed to establish a histologic grading scheme and scoring system. A total of 215 cases of salivary gland SCs diagnosed between 1994 and 2021 were obtained from the tumor registries of the authors. Eighty cases were originally diagnosed as something other than SC, most frequently acinic cell carcinoma. Lymph node metastases were identified in 17.1% (20/117 cases with available data), with distant metastasis in 5.1% (6/117). Disease recurrence was seen in 15% (n=17/113 cases with available data). The molecular genetic profile showed ETV6 :: NTRK3 gene fusion in 95.4%, including 1 case with a dual fusion of ETV6 :: NTRK3 and MYB :: SMR3B . Less frequent fusion transcripts included ETV6 :: RET (n=12) and VIM :: RET (n=1). A 3-tiered grading scheme using 6 pathologic parameters (prevailing architecture, pleomorphism, tumor necrosis, perineural invasion (PNI), lymphovascular invasion (LVI), and mitotic count and/or Ki-67 labeling index) was applied. Grade 1 histology was observed in 44.7% (n=96), grade 2 in 41.9% (n=90), and grade 3 in 13.5% (n=29) of cases. Compared with low-grade and intermediate-grade SC, high-grade tumors were associated with a solid architecture, more prominent hyalinization, infiltrative tumor borders, nuclear pleomorphism, presence of PNI and/or LVI, and Ki-67 proliferative index >30%. High-grade transformation, a subset of grade 2 or 3 tumors, seen in 8.8% (n=19), was defined as an abrupt transformation of conventional SC into high-grade morphology, sheet-like growth, and a tumor lacking distinctive features of SC. Both overall survival and disease-free survival (5 and 10 y) were negatively affected by tumor grade, stage, and TNM status (each P <0.0001). SC is a low-grade malignancy with predominantly solid-microcystic growth patterns, driven by a gene fusion, most commonly ETV6 :: NTRK3 . There is a low risk for local recurrence and a good overall long-term survival, with a low risk for distant metastasis but a higher risk for locoregional lymph node metastasis. The presence of tumor necrosis, hyalinization, PNI and/or LVI, and positive resection margins correlate with higher tumor grade, less favorable prognosis, and increased mortality. The statistical results allowed us to design a 3-tiered grading system for salivary SC.

Acinic cell carcinoma of the oral and maxillofacial region: an international multicenter study

The aim of this study was to describe the prevalence, clinicopathological, and prognostic features of acinic cell carcinoma (AciCC) of the oral and maxillofacial region. AciCC cases were retrospectively retrieved from 11 pathology centers of three different countries. Medical records were examined to extract demographic, clinical, pathologic, and follow-up information. A total of 75 cases were included. Females (65.33%) with a mean age of 45.51 years were mostly affected. The lesions usually presented as an asymptomatic (64.28%) nodule (95.66%) in the parotid gland (70.68%). The association of two histopathological patterns was the most common finding (48.93%) and the tumors presented mainly conventional histopathological grades (86.11%). Surgical treatment was performed in the majority of the cases (59.19%). Local recurrence was observed in 20% of the informed cases, regional metastasis in 30.43%, and distant metastasis in 12.50%. The statistical analysis showed that the cases with a solid histopathological pattern (p=0.01), high-grade transformation (p=0.008), recurrence (p=0.007), and regional metastasis (p=0.03) were associated with poor survival. In conclusion, high histopathological transformation, presence of nodal metastasis, and recurrence were prognostic factors for AciCC of the oral and maxillofacial region.

A Parotid Gland Mammary Analogue Secretory Carcinoma in a 4-Year-Old Boy: Case Report and Literature Review

Background: Mammary analogue secretory carcinoma (MASC) is characterized by similar histologic, immunohistochemical, and molecular features with breast secretory carcinoma. MASC usually occurs in adults. Case report: A 4-year-old boy presented with a right infra-auricular mass. Features of the tumor include solid, tubular, and papillary growth patterns, with homogenous eosinophilic secretions inside microcystic structures. Immunohistochemical stains showed strong, diffuse staining for CK7, S100, pan-TRK protein. P63 was positive in a peripheral pattern. Fluorescence in situ hybridization (FISH) analysis showed the characteristic ETV6-NTRK3 gene fusion. Conclusion: Typical histological, immunohistochemical, and molecular features are present in MASC occurring early in childhood.

Diagnostic accuracy of pan-TRK immunohistochemistry in differentiating secretory carcinoma from acinic cell carcinoma of salivary gland-A systematic review

BACKGROUND

Secretory carcinoma (SC) is a well-established salivary gland malignancy that has earned its popularity for its unique clinicopathological behavior. Although it is an indolent malignancy, few of them have been reported with high grade transformation making it mandatory to differentiate it from its prime histological mimicker, acinic cell carcinoma (AciCC). Recently, many studies have been directed toward validating the sensitivity and specificity of pan-TRK IHC for confirming ETV6::NTRK3 gene fusion in SCs involving salivary gland.

AIM

The aim of the present systematic review was to establish the diagnostic utility of pan-TRK immunostaining in histological differentiation of SC from AciCC.

MATERIAL AND METHODS

An electronic search was carried out using MEDLINE by PubMed, Scopus, Google scholar, Trip, Cochrane library and EMBASE databases. Articles in which SC assessed with pan-TRK immunohistochemical expressions were included for systematic review and their staining pattern (cytoplasmic, nuclear and/or combined), sensitivity, specificity, positive as well as negative predictive were gathered. Risk of bias was analyzed for each study using QUADAS-2 tool.

RESULTS

Thirteen eligible articles were included for the quantitative analysis, which revealed positive immunostaining of pan-TRK by nearly all the ETV6::NTRK3 fusion prevalent SCs alongside negative expression in almost all the cases of AciCC with 100% of sensitivity as well as specificity.

CONCLUSION

The evidence from the included studies supports that pan-TRK immunostaining could be used as a reliable preliminary screening tool for discerning SC from AciCC. PROSPERO No: CRD42022308913.

Morphologic and Ancillary Studies of Pediatric Acinic Cell Carcinoma: A Single Institute Experience

BACKGROUND

Acinic cell carcinoma (AciCC) is the second most common pediatric malignant salivary gland tumor. However, there are limited pathology publications about this tumor in the pediatric population.

METHODS

We describe four pediatric AciCC cases diagnosed between 2000 and 2021 in our institute. Reticulin histochemistry plus immunohistochemistry for NR4A3 and DOG1 were performed on all cases.

RESULTS

Histologically, all four cases featured a tumor-associated lymphoid proliferation and collagenous stroma, in which two formed central scars. The tumors were predominantly solid, with a lobular pattern and variably sized dilated spaces, including one case with focal microcysts. High-grade transformation was not observed in any of our cases. Reticulin stain and immunohistochemistry for NR4A3 showed distinct features between AciCC and non-neoplastic salivary gland parenchyma. DOG1 immunohistochemistry confirmed the acinar origin of AciCC.

CONCLUSIONS

Our study reveals that pediatric AciCCs often present with tumor-associated lymphoid proliferation (TALP) and sclerosis. Special stains such as reticulin histochemistry and NR4A3 immunohistochemistry are helpful to separate tumor from adjacent benign parenchyma. The ancillary study is helpful for the diagnosis of small specimens. Our study is limited by its low case number, but we hope that our results will promote more studies on this rare salivary gland tumor in the pediatric population.

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 salivary gland: a multi-institutional clinicopathologic study of 90 cases with emphasis on grading and prognostic factors

Secretory carcinoma (SC) is a rare form of salivary carcinoma that was first described in 2010 and is characterized by ETV6::NTRK3 fusion in most cases. In this large retrospective study, we aimed to identify adverse clinicopathologic factors and propose a prognostically relevant grading scheme for SC.

METHODS

A detailed clinicopathologic review was conducted on 90 SCs from the major and minor salivary glands.

RESULTS

The median age at presentation was 50 years (range: 7-93). Sixty-nine (77%) tumours originated from major salivary glands, whereas the remaining 21 involved minor salivary glands.Six cases (7%) had cervical nodal metastasis. Only lymphovascular invasion (LVI) was associated with a risk of nodal metastasis (P < 0.05). The 5-year disease-specific survival and disease-free survival (DFS) were 98% and 87%, respectively. On univariate survival analysis, adverse prognostic factors associated with decreased DFS included minor salivary gland origin, atypical mitosis, high mitotic index, high-grade transformation (HGT), necrosis, nuclear pleomorphism, infiltrative tumour border, fibrosis at the invasive front, LVI, positive margin, and advanced pT stage (P < 0.05). When adjusted for pT stage and margin status, mitotic index, LVI, nuclear pleomorphism, and HGT remained as independent prognostic factors.

CONCLUSION

We therefore propose a two-tiered grading system for SC. The low-grade SC is defined as those with <5 mitoses /10 high-power fields and no tumour necrosis, and high-grade SC as those with ≥5 mitoses /10 high-power fields and/or necrosis. This proposed grading system can be useful to risk stratify patients with SC for appropriate clinical management.

NTRK3 mutation in secretory carcinoma of the parotid gland: A Case report

Mammary analog secretory carcinoma (MASC) is a newly described carcinoma with a molecular hallmark of ETV6-NTRK3 fusion that promotes oncogenesis. While MASC histopathology was well-studied in the literature, clinical behavior remains unstudied. We present a 22-year-old man with painless parotid mass, which was diagnosed as salivary gland cancer, MASC subtype.

Head and Neck Acinic Cell Carcinoma: A New Grading System Proposal and Diagnostic Utility of NR4A3 Immunohistochemistry

Acinic cell carcinoma (AciCC) is traditionally considered as a low-grade salivary gland carcinoma. However, a subset demonstrates high-grade features with a higher mortality rate and distant metastasis. In this large retrospective study of 117 cases, we aimed to establish a histologic grading scheme for AciCC. Adverse independent prognostic factors identified on the multivariate analysis included older age, tumor necrosis, nuclear anaplasia, lymphovascular invasion, absence of tumor-associated lymphoid stroma, and high American Joint Committee on Cancer (AJCC) pT and pN stages. A 3-tiered grading scheme using 4 pathologic parameters (mitotic index, necrosis, tumor border, and fibrosis at the frankly invasive front) was subsequently applied. Compared with low/intermediate-grade, high-grade AciCC defined as a mitotic index ≥5/10 HPFs and/or necrosis was an independently adverse prognostic factor. The 5-year overall survival was 50% in high-grade AciCCs, and 100% in low-grade or intermediate-grade AciCCs. Compared with low-grade or intermediate-grade AciCC, high-grade tumors were associated with older age, larger tumor size, focal rather than diffuse zymogen granules, solid architecture, infiltrative tumor border, fibrosis at the frankly invasive front, lymphovascular invasion, perineural invasion, positive margin, high pT, and pN stages. NR4A3 was a highly sensitive and specific immunohistochemical stain for diagnosing AciCC with a sensitivity and specificity of 96% and 93%, respectively. In conclusion, although we proposed a 2-tiered grading system for AciCC with high-grade tumors defined by a mitotic count ≥5/10 HPFs and/or necrosis, more studies are needed to assess the prognostic value of intermediate grade. NR4A3 immunohistochemical stain is a useful diagnostic marker for AciCC.

Analysis of clinicopathologic features and expression of NR4A3 in sinonasal acinic cell carcinoma

Acinic cell carcinoma (AiCC) in the nasal cavity and paranasal sinuses has rarely been reported in literature. A recent study demonstrated that recurrent genomic rearrangement [t(4;9) (q13;q31)] is a driver event in AiCC of the salivary glands that could promote the upregulation of transcription factor nuclear receptor subfamily 4 group A member 3 (NR4A3). In the current study, we evaluated the clinicopathological characteristics and expression of NR4A3 in four new cases of sinonasal AiCC. All four patients were men (range, 27-70 years). The tumor involved only the nasal cavity in two patients, while the other two patients showed involvement of both the nasal cavity and ethmoid sinus. Histologically, the tumor displayed a predominantly solid growth pattern and was composed of hematoxyphilic serous-like cells and scattered intercalated duct-like cells. Immunohistochemically, all cases expressed DOG-1. However, staining for mammaglobin, S-100, CA9, and P63 was absent in all patients. All four cases showed positive nuclear staining for NR4A3. In contrast, none of the other 39 sinonasal tumors, including secretory carcinomas, pleomorphic adenomas, mucoepidermoid carcinomas, adenoid cystic carcinomas, renal cell-like adenocarcinomas, intestinal-type adenocarcinomas, non-intestinal-type adenocarcinomas, extraskeletal myxoid chondrosarcoma, and carcinoma ex pleomorphic adenomas, presented with any positive NR4A3 nuclear staining. Additionally, NR4A3 rearrangements were observed in three cases with sinonasal AiCC by fluorescence in situ hybridization, and the expression level of NR4A3 mRNA was significantly increased in sinonasal AiCC compared with that in normal parotid tissue. Our study demonstrated that sinonasal AiCCs are characterized by an indolent nature and histopathological similarity to parotid AiCCs. Moreover, NR4A3 is a reliable biomarker for distinguishing sinonasal AiCCs from other sinonasal carcinomas.

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.

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.

Squamoglandular Variant of Acinic Cell Carcinoma: A Case Report of a Novel Variant

While salivary gland tumors have considerable plasticity, juxtaposition of the morphologies of two named tumor types is rare. Tumors with both mucoepidermoid and serous acinar components, dubbed "mucoacinar" carcinomas were recently characterized, and based on morphologic and molecular features, considered variants of mucoepidermoid carcinoma. Here we describe a unique case of a 59-year-old male with a 0.9 cm right parotid mass with a similar blend of mucoepidermoid-like and acinar elements that instead has a molecular phenotype of acinic cell carcinoma, essentially the reverse of mucoacinar carcinoma. The tumor was fairly well circumscribed with a prominent tumor associated lymphoid response. It consisted of a predominant bland but basaloid squamoid proliferation with scattered pockets of serous acinar differentiation as well as rare mucous cells and tubules. The tumor showed diffuse cytokeratin and DOG1 reactivity as well as p40 expression in the squamoid components. Immunostaining for NR4A3 was diffusely positive, and an NR4A3 rearrangement was noted on fluorescence in situ hybridization, while testing for MAML2 and MSANTD3 rearrangements were negative. Based on these findings, this tumor is best considered a "squamoglandular variant of acinic cell carcinoma." Morphologic and clinical evidence argues against this representing a form of high-grade transformation. While overall bland, the differential diagnosis may include various basaloid tumors in the parotid gland, both primary and metastatic.

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.

Imaging identification of primary mammary analogue secretory carcinoma and acinic cell carcinoma in major salivary glands

OBJECTIVE

The present study aimed to characterize and differentiate the ultrasonography (US) and computed tomography (CT) features of mammary analogue secretory carcinoma (MASC) and acinic cell carcinoma (AciCC).

METHODS AND PATIENTS

A total of 83 patients with clinically proven MASC and AciCC were analyzed. The following characteristics were assessed on US, CT, and magnetic resonance imaging: lesion size, shape, margin, echogenicity, echotexture, cystic components, posterior echo, vascularity, density, degree of enhancement, enhancement pattern, signal intensity (SI) on T1- and T2-weighted images (WI), hemorrhages, and lymph node enlargement.

RESULTS

Similarities were observed between the imaging performance of MASC and AciCC. Differences between the two characteristics of shape on US and cystic components on CT were statistically significant. The proportion of MASC to regular shape on US (p = 0.006) and cystic components on CT (p = 0.027) was significantly higher than that of AciCC. Regular shape on US had the highest sensitivity in the identification of MASC and AciCC, while regular shape on US + cystic component on CT had the highest specificity.

CONCLUSIONS

The shape on US and cystic components on CT are key characteristics for distinguishing MASC and AciCC.

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.

Cytopathology of acinic cell carcinoma: A study of 50 cases, including 9 with high-grade transformation

BACKGROUND

Although largely readily recognizable in tissue sections, acinic cell carcinoma (ACC) remains diagnostically problematic in fine-needle aspiration (FNA) cytopathology. The authors undertook an analysis of a large series of ACC aspirates, including acinic cell carcinoma with high-grade transformation (ACC-HGT).

METHODS

The authors searched their cytopathology files for ACC cases with histopathologic confirmation. FNA biopsy was performed according to standard techniques.

RESULTS

Fifty FNA biopsy cases of ACC (including 36 of parotid origin [72%]) from 41 patients (female to male ratio, 1.4:1; age range, 23-84 years; average, 54 years) met the study inclusion requirements. Primary neoplasm aspirates were most common (72%), and they were followed by recurrent tumors (16%) and metastases (12%). A precise cytologic diagnosis was made for 64%. Three of 9 ACC-HGT cases (33%) were correctly interpreted as such; 98% of conventional ACC cases were correctly graded as low-grade. With the Milan classification system, 74% fit into the malignant category. Ancillary testing was performed for only 36%. Conventional ACC had moderately to highly cellular smears; monotonous cells in aggregates and single forms; rounded nuclei; and microvacuolated, finely granular, oncocyte-like, or nonspecific cytoplasm. ACC-HGT smears contained larger nuclei, high nuclear to cytoplasmic ratios, coarse nuclear chromatin, and a loss of cytoplasmic granules/vacuoles.

CONCLUSIONS

A correct diagnosis of ACC via FNA biopsy was made in almost two-thirds of the cases. With the Milan classification, 84% of the cases would have been classified as malignant or suspicious for malignancy. An absence of conventional serous acinar cell morphology in some cases as well as an absence of ancillary immunohistochemistry testing in almost two-thirds of the cases prevented even better diagnostic performance.

Reevaluation of Salivary Lymphadenoma: A Subgroup Identified as Warthin-like Mucoepidermoid Carcinoma Following Molecular Investigation for MAML2 Rearrangement

CONTEXT.—

Both salivary lymphadenomas (LADs) and Warthin-like mucoepidermoid carcinoma (MEC) contain components of epithelium and lymphoid stroma and their differential diagnosis can be difficult on the basis of morphology alone.

OBJECTIVE.—

To clarify whether Warthin-like MEC was diagnosed as a LAD, and to compare their clinicopathologic features.

DESIGN.—

A total of 16 LAD cases were analyzed for MAML2 rearrangement by using fluorescence in situ hybridization, and the clinical, histologic, immunohistochemical, and prognostic features were compared between MAML2 rearrangement-positive and MAML2 rearrangement-negative groups.

RESULTS.—

Among the 16 cases investigated, 9 harbored a MAML2 rearrangement and were reclassified as Warthin-like MEC. The remaining 7 cases were classified as LADs with 1 nonsebaceous and 6 sebaceous cases. The patients with Warthin-like MEC had a wider age range (10-75 years) than the patients with LADs (36-68 years). Histologically, 2 of the 9 Warthin-like MECs (22.2%) showed focal invasion, whereas all the LADs had complete capsules. Warthin-like MECs exhibited a diverse epithelial cell morphology, including basaloid, glandular, cuboidal, epidermoid, with mucinous cells, although these cytologic features were seen only focally in some cases. Nonsebaceous LAD was composed of basaloid and glandular epithelial cells predominantly. In sebaceous LAD, the epithelial cells were composed of basaloid and large foamy sebaceous cells. In all cases, the stroma was composed mainly of lymphocytes accompanied by lymphoid follicles, although plasma cell infiltration could be much heavier in Warthin-like MEC. All the patients had a good outcome after a longer follow-up (3-166 months).

CONCLUSIONS.—

Warthin-like MEC can be misdiagnosed as a LAD owing to overlap in clinicopathologic features of the 2 entities. Careful histologic evaluation and detection of MAML2 rearrangement can facilitate their differential diagnosis.

The Decline of Salivary Adenocarcinoma Not Otherwise Specified as a Tumor Entity: Reclassification Using Contemporary Immunohistochemical Profiling and Diagnostic Criteria

The classification of salivary gland carcinomas has become increasingly specific over the last decade with the definition of new tumor types, documentation of novel molecular and immunohistochemical findings, and development of more refined diagnostic criteria. In this setting, it is unclear how many salivary tumors still cannot be easily categorized-and whether such tumors represent undifferentiated malignancies or include additional definable entities. Relying largely on current classification schemes and contemporary immunohistochemical panels, we reassessed salivary tumors previously diagnosed as adenocarcinoma, not otherwise specified (ACA NOS) from 2 large academic medical centers. Fifty-seven ACA NOS (72%) could be reclassified as more specific entities including 31 salivary duct carcinomas (39%), 7 polymorphous adenocarcinomas (9%), 5 epithelial-myoepithelial carcinomas (6%), 4 myoepithelial carcinomas (5%), 4 secretory carcinomas (5%), 1 acinic cell carcinoma (1%), 1 basal cell adenocarcinoma (1%), 1 intraductal carcinoma (1%), and 1 clear cell carcinoma (1%) as well as 2 metastatic squamous cell carcinomas (3%). Of reclassified cases, 21 (37%) represented variant histologies within these categories. ACA NOS comprised 11% of salivary malignancies before reclassification, but only 4% after reclassification. The remaining 22 ACA NOS demonstrated heterogeneous features, with an association between histologic grade and clinical outcome. In effect, ACA NOS is becoming a bygone entity as modern classification schemes and ancillary techniques now permit more specific typing of a majority of these tumors, potentially facilitating more specific prognostication and treatment. Additional distinctive entities such as mucinous adenocarcinoma may still be definable within the ACA NOS category.

NR4A3 (NOR-1) Immunostaining Shows Better Performance than DOG1 Immunostaining in Acinic Cell Carcinoma of Salivary Gland: a Preliminary Study

Objectives

Acinic cell carcinoma of salivary gland harbours recurrent and specific chromosomal rearrangement [t(4;9)(q13;q31)], resulting in the translocation of secretory calcium-binding phosphoprotein gene cluster at 4q13 to nuclear receptor subfamily 4 group a member 3 at 9q31. This upregulates the transcription factor nuclear receptor subfamily 4 group A member 3, which can be detected by immunohistochemistry. The purpose of this pilot study is to evaluate the performance of nuclear receptor subfamily 4 group A member 3 immunostaining on whole-slide acinic cell carcinoma tissue, in comparison with discovered on GIST-1 immunostaining.

Material and Methods

We retrieved 6 cases of acinic cell carcinoma (AciCC), including 5 conventional low-grade and 1 dedifferentiated high-grade. Immunohistochemistry (IHC) for nuclear receptor subfamily 4 group A member 3 (NR4A3) and discovered on GIST-1 (DOG1) were performed at the University of Pittsburgh Medical Centre in Pittsburgh, Pennsylvania on all retrieved cases.

Results

The result shows that NR4A3 IHC shows better performance than DOG1 IHC: 5 of the 6 (83.3%) AciCC cases (including the dedifferentiated high-grade) demonstrated strong diffuse nuclear staining for NR4A3, also five AciCC cases (including the dedifferentiated high-grade) demonstrated weak to moderate membranous staining with variable distribution for DOG1. Moreover, only 3 (50%) cases showed complete membranous staining with DOG1.

Conclusions

This pilot study showed that nuclear receptor subfamily 4 group A member 3 immunostaining is a sensitive marker for acinic cell carcinoma and of better utility than discovered on GIST-1 immunostaining in making a diagnosis of acinic cell carcinoma.

Clinicopathological analysis of oral and maxillofacial acinic cell carcinoma: A systematic review

BACKGROUND

The aim of the present systematic review was to analyze the available data regarding acinic cell carcinoma of the oral and maxillofacial region.

METHODS

A search strategy was performed using PubMed, Web of Science, Scopus, and Embase electronic databases.

RESULTS

Available data revealed a slight female preference (54.73%) and a mean age at diagnosis of 47.51 ± 19.85 years. The parotid glands (67.72%) were most frequently affected, and most cases were asymptomatic (69.54%). A microcystic histopathological pattern was reported in 21.56% of the cases, and the Periodic acid-Schiff was the staining method most frequently used, after the hematoxylin and eosin staining, in the tumors analyzed. The lesions were mainly treated by surgical removal (72.32%). Recurrence was reported in 81 cases (27.83%) and metastasis in 100 (42.91%). Statistical data analysis revealed that tumors located in major salivary glands and exhibiting high-grade histology were associated with local recurrence (P = .01). In addition, the patients older than 57 years, lesions with bone involvement, the high-grade tumors and the cases with a history of recurrence and metastasis were associated with a lower overall survival (P < .05).

CONCLUSION

By assembling all eligible cases in the literature, the present systematic review determined the most common clinicopathological profile of acinic cell carcinoma and the most relevant prognostic factors in a distinctly representative sample. The survey demonstrated the importance of considering the histopathological grading in order to better define the treatment for each case.

Acinic cell carcinoma of the salivary gland in the adult and paediatric population: a survival analysis

BACKGROUND

Acinic cell carcinoma (AcCC) is a rare malignant neoplasm of the salivary glands and generally considered to be a low-grade tumour. Surgical treatment is often curative, but a more aggressive high-grade variant has been associated with poorer survival and propensity for distant metastasis. No standard treatment guidelines exist and the approach to treatment is varied in the published series. The aim of this study is to present the experience of three major hospitals in Sydney, Australia, in treating AcCC of the salivary gland, with a focus on clinico-pathological features of disease and their associations with survival outcomes.

METHODS

Adult and paediatric cases of AcCC of the salivary gland during the time period 1979-2018 were retrospectively included. Demographic, clinico-pathological, treatment and survival outcome data were extracted. Survival analysis was undertaken to assess the effect of clinical and pathological variables on overall and disease-free survival.

RESULTS

Thirty-two cases were reviewed (29 adult and three paediatric). Thirty tumours (93.8%) were parotid gland primary tumours. Mean overall and disease-free survival was 17.0 ± 0.7 and 16.0 ± 0.9 years, respectively. Features associated with poorer survival were cT staging >1, presence of preoperative clinical facial nerve deficit and local recurrence. Positive margins were associated with recurrence.

CONCLUSION

These data suggest that disease-free and overall survival in AcCC of the salivary gland is excellent with surgery as the first-line treatment. Poor survival outcomes are uncommon and may be associated with locally advanced disease in the presence of other well-established high-risk features.

Clinicopathologic Features and Survival Trends for Acinic Cell Carcinoma of the Major Salivary Glands: A Surveillance, Epidemiology, and End Results Population Analysis

Background

We analyzed a population-based national registry to identify the most influential patient pretreatment and treatment factors affecting overall survival (OS) and cause-specific survival (CSS) in patients diagnosed with acinic cell carcinoma (ACC) of the major salivary glands.

Methods

Using the Surveillance, Epidemiology, and End Results (SEER) database of the US National Cancer Institute (NCI) related to survival, a total of 1,254 patients with diagnosed ACC of the major salivary glands from 1975 to 2016 met inclusion criteria. Factors significant for OS and CSS were determined using univariate and multivariate analysis with the Cox proportional hazards model.

Results

Univariate OS analysis demonstrated that surgery favorably influenced longer survival compared to no surgery (hazard ratio (HR) 2.35, P < 0.05). Patient age was found to be highly predictive of superior OS (divided into 10-year age bands, P < 0.0001, younger age better). In multivariate OS analysis, there were statistically significant worse outcomes for men (HR 1.54, P < 0.05), grades III/IV (HR 2.5, P < 0.05), and distant disease (HR 3.55, P < 0.05) or regional disease (HR 1.22, P < 0.05). Patients diagnosed during years 1996 - 2016 had better OS when compared to earlier decades 1975 - 1995 (HR 1.38, P < 0.05). In univariate analysis, the mean CSS for grades I, II, and III/IV were 429 months (95% confidence interval (CI), ± 38.39), 426 months (95% CI, ± 25.73) and 198 months (95% CI, ± 66.38). Multivariate analysis of CSS further demonstrated that there were statistically significant worse outcomes for men (HR 1.68, P < 0.05), grade III/IV (HR 3.2, P < 0.05), tumor size greater than 40 mm (P < 0.001), and distant disease (HR 4.48, P < 0.05) or regional disease (HR 1.84, P < 0.05).

Conclusions

To our knowledge, this is the largest population-based study of OS and CSS of major salivary gland ACC. We found that the patient pretreatment and treatment factors including younger age at diagnosis, female sex, early stage, lower grade, surgical excision, and recent year of diagnosis are associated with improved survival in patients diagnosed with ACC of the major salivary glands. We hope that this information will aid in construction of further research projects that better refine optimal treatment protocol of individualized patient care.

NR4A3 Immunohistochemistry Reliably Discriminates Acinic Cell Carcinoma from Mimics

Acinic cell carcinoma (AciCC) harbors a recurrent t(4;9)(q13;q31) translocation, which leads to upregulation of Nuclear Receptor Subfamily 4 Group A Member 3 (NR4A3). Previous work on tissue microarrays suggests that NR4A3 immunohistochemistry (IHC) may be useful in the diagnosis of AciCC. Thus far, only a single study has evaluated the utility of NR4A3 immunohistochemistry (IHC) in the diagnosis of AciCC, using a tissue microarray to assess most non-AciCC tumor types. Herein we evaluate the diagnostic performance of NR4A3 IHC for AciCC in a large cohort of 157 salivary gland tumors, using whole tissue sections. The cohort consisted of 37 AciCC (6 of them (16%) with high grade transformation), 30 secretory carcinomas (SC), and 90 additional salivary gland tumors, including mucoepidermoid carcinomas (MEC), polymorphous adenocarcinomas (PAC), pleomorphic adenomas (PA), salivary duct carcinomas (SDC), and adenoid cystic carcinomas (AdCC). NR4A3 nuclear staining by IHC was considered positive if present in more than 5% of tumor cells. Overall, 92% of AciCC (34/37) expressed NR4A3 by IHC, with strong (89%) or moderate (3%) nuclear staining, yielding a sensitivity of 92%. IHC detected NR4A3 expression in all cases of recurrent/metastatic AciCC and tumors with high grade transformation. Importantly, all SC were negative for NR4A3 IHC, with no staining in 28/30 cases and weak focal staining, in < 5% of cells, in 2/30 (7%). Similarly, all MEC (20/20), SDC (20/20) and AdCC (10/10) were negative for NR4A3 by IHC, as were most PA (18/20; 15%) and PAC (18/20; 5%). Two PA and two PAC showed multifocal expression of NR4A3 in more than 5% of cells, of weak intensity in 3 cases and moderate in 1 PAC, yielding an overall specificity of 97% for NR4A3 IHC for the diagnosis of AciCC. In conclusion, NR4A3 is a highly sensitive and specific immunohistochemical marker for AciCC; moderate to strong and/or diffuse NR4A3 expression is a consistent and diagnostic feature of AciCC.

A case of mammary analogue secretory carcinoma of the parotid gland: A case report

RATIONALE

Mammary analogue secretory carcinoma is a low grade salivary gland malignancy, first described by Skalova et al in 2010. The histological, immunohistochemical, and molecular characteristics of this tumor resemble those of secretory carcinoma of the breast.

PATIENT CONCERNS

A 40-year-old male patient without any specific past history came with complaints of 4 cm-sized hard, fixed, right infra-auricular mass without tenderness. There was no enlarged or enhancing lymph node in both neck.

DIAGNOSES

Fine needle aspiration biopsy was done for right parotid mass and pathologic report was "lymphocytes only" that suggested benign or low-grade malignant parotid tumor.

INTERVENTIONS

Partial parotidectomy including mass excision was performed. Operative finding showed hard bluish mass located in deep lobe of right parotid gland.

OUTCOMES

Final pathologic report revealed secretory carcinoma of parotid gland. Homogenous eosinophilic secretions were identified inside microcystic structure. The immunophenotype was positive for epithelial membrane antigen, vimentin, S-100 protein. After 15 months of the surgery, the patient showed negative evidence of disease state.

LESSONS

We present here a case of mammary analogue secretory carcinoma of the parotid gland to help further characterize this rare tumor.

A clinicopathologic study of secretory carcinoma of minor salivary gland: a series of 4 cases and diagnostic considerations

OBJECTIVE

Secretory carcinoma (SC) of salivary gland is a recently described low-grade malignant neoplasm of the salivary gland, characterized by rearrangement of the ETV6 gene. SC of salivary gland shares striking morphologic, immunophenotypic, and molecular similarity to SC of breast.

STUDY DESIGN

We report the clinicopathologic features of 4 ETV6-rearranged SCs of minor salivary gland and histopathologic diagnostic considerations.

RESULTS

Two cases were located in the lip, 1 in the soft palate, and 1 in the mandibular vestibule. No patient presented with regional or distant metastases at diagnosis. All cases were positive for S100 protein and mammaglobin, and all cases were negative for p63. All cases were positive for ETV6 rearrangement.

CONCLUSIONS

SC of the minor salivary glands are rare. Because of its shared histopathologic features with other salivary gland tumors, positivity for ETV6 gene rearrangements is recommended before rendering a diagnosis of SC of salivary gland.

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.

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.

The HTN3-MSANTD3 Fusion Gene Defines a Subset of Acinic Cell Carcinoma of the Salivary Gland

The spectrum of tumors arising in the salivary glands is wide and has recently been shown to harbor a network of tumor-specific fusion genes. Acinic cell carcinoma (AciCC) is one of the more frequently encountered types of salivary gland carcinoma, but it has remained a genetic orphan until recently when a fusion between the HTN3 and MSANTD3 genes was described in one case. Neither of these 2 genes is known to be implicated in any other malignancy. This study was undertaken to investigate whether the HTN3-MSANTD3 fusion is a recurrent genetic event in AciCC and whether it is a characteristic of one of its histological variants. Of the 273 AciCCs screened, 9 cases showed rearrangement of MSANTD3 by break-apart fluorescence in situ hybridization, 2 had 1 to 2 extra signals, and 1 had gain, giving a total of 4.4% with MSANTD3 aberrations. In 6 of 7 available cases with MSANTD3 rearrangement, the HTN3-MSANTD3 fusion transcript was demonstrated with real-time polymerase chain reaction. Histologically, all fusion-positive cases were predominantly composed of serous tumor cells growing in solid sheets, with serous tumor cells expressing DOG-1 and the intercalated duct-like cell component being CK7 positive and S-100 positive in 6/9 cases. All but one case arose in the parotid gland, and none of the patients experienced a recurrence during follow-up. In contrast, the case with MSANTD3 gain metastasized to the cervical lymph nodes and lungs. In conclusion, we find the HTN3-MSANTD3 gene fusion to be a recurrent event in AciCC with prominent serous differentiation and an indolent clinical course.

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.

Ancillary testing in salivary gland cytology: A practical guide

Salivary gland cytology is challenging, and historically the role of ancillary testing has been limited. However, numerous molecular/genetic advances in the understanding of salivary gland neoplasms during the last decade have facilitated the development of many useful diagnostic markers, such as PLAG1 and HMGA2 immunohistochemistry for pleomorphic adenoma and ETV6 fluorescence in situ hybridization for secretory carcinoma. Numerous salivary gland neoplasms are characterized by specific molecular/genetic alterations, many of which can be identified on cytologic preparations by karyotype analysis, fluorescence in situ hybridization, or immunohistochemical surrogates. Next-generation sequencing also has potential diagnostic applications, although to the authors' knowledge it currently has no routine role in salivary cytology. The primary goal of salivary fine-needle aspiration (FNA) is to facilitate appropriate clinical management. Ancillary testing has greatly enhanced the ability for accurate classification as per The Milan System for Reporting Salivary Gland Cytopathology and allows for the definitive diagnosis of many salivary FNA specimens, and also may resolve diagnostic uncertainty for FNAs that may be classified in The Milan System for Reporting Salivary Gland Cytopathology categories of salivary gland neoplasm of uncertain malignant potential or suspicious for malignancy. This review provides an updated discussion of the molecular/genetic features of the more commonly encountered salivary neoplasms by FNA, and discusses the application of available diagnostic immunohistochemical and molecular tests in salivary gland cytology.

Molecular Profiling of Salivary Gland Intraductal Carcinoma Revealed a Subset of Tumors Harboring NCOA4-RET and Novel TRIM27-RET Fusions: A Report of 17 cases

Intraductal carcinoma (IC) is the new World Health Organization designation for tumors previously called "low-grade cribriform cystadenocarcinoma" and "low-grade salivary duct carcinoma." The relationship of IC to salivary duct carcinoma is controversial, but they now are considered to be distinct entities. IC is a rare low-grade malignant salivary gland neoplasm with features similar to mammary atypical ductal hyperplasia or ductal carcinoma in situ, that shows diffuse S100 protein and mammaglobin positivity and is only partially defined genetically. (Mammary analogue) secretory carcinoma harboring ETV6-NTRK3, and in rare cases ETV6-RET fusion, shares histomorphologic and immunophenotypical features with IC. Recently, RET rearrangements and NCOA4-RET have been described in IC, suggesting a partial genetic overlap with mammary analogue secretory carcinoma. Here, we genetically characterize the largest cohort of IC to date to further explore this relationship. Seventeen cases of IC were analyzed by next-generation sequencing using the FusionPlex Solid Tumor kit (ArcherDX). Identified fusions were confirmed using fluorescence in situ hybridization break apart and, in some cases, fusion probes, and a reverse transcription polymerase chain reaction designed specifically to the detected breakpoints. All analyzed cases were known to be negative for ETV6 rearrangement by fluorescence in situ hybridization and for ETV6-NTRK3 fusion by reverse transcription polymerase chain reaction. Next-generation sequencing analysis detected a NCOA4-RET fusion transcript joining exon 7 or 8 of NCOA4 gene and exon 12 of RET gene in 6 cases of intercalated duct type IC; and a novel TRIM27-RET fusion transcript between exons 3 and 12 in 2 cases of salivary gland tumors displaying histologic and immunohistochemical features typical of apocrine IC. A total of 47% of IC harbored a fusion involving RET. In conclusion, we have confirmed the presence of NCOA4-RET as the dominant fusion in intercalated duct type IC. A novel finding in our study has been a discovery of a subset of IC patients with apocrine variant IC harboring a novel TRIM27-RET.

Ectopic ACTH Production and Cushing's Syndrome in a Patient with Parotid Acinic Cell Carcinoma with High-Grade Transformation: Tumor Context and Clinical Implications

We report a rare case of Cushing's syndrome in a 59-year-old man who initially presented with concurrent acinic cell carcinoma of the parotid with high-grade transformation and co-existing papillary and medullary thyroid carcinomas, without noticeable cushinoid symptoms. Six-months later, he developed clinical features of Cushing's syndrome which coincided with disease progression in the form of lung metastasis and mediastinal lymphadenopathy. Ectopic adrenocorticotropic hormone (ACTH) production and protein expression was limited to the high-grade transformed component of acinic cell carcinoma and in the lymph node metastasis, and was absent in the conventional acinic cell carcinoma as well as in the papillary and medullary thyroid carcinoma. He received adjuvant chemotherapy and supportive management with interval improvement for 8 months followed by disease progression with increasing serum cortisol levels and bone metastasis. He was offered palliative chemotherapy, however, declined further therapy and was lost to follow up. We discussed clinical and pathologic implications of ectopic ACTH production associated with acinic carcinoma and also reviewed the literature of this rare paraneoplastic syndrome.

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 presenting as a cystic parotid mass

We present a case of a 63-year-old male with an 8-year history of a left-sided cystic facial mass which recurred despite multiple drainage procedures. Imaging findings showed a cystic mass in the left parotid gland and it was surgically resected. Pathology confirmed it to represent a mammary analogue secretory carcinoma, a relatively newly described entity. This case illustrates that mammary analogue secretory carcinoma can masquerade as a cyst within the parotid gland.

Immunohistochemistry with a pan-TRK antibody distinguishes secretory carcinoma of the salivary gland from acinic cell carcinoma

AIMS

Secretory carcinoma (previously known as mammary analogue secretory carcinoma) is characterised by ETV6 rearrangements, most often ETV6-NTRK3 fusion. Given its histological overlap with other salivary gland tumours, secretory carcinoma can be difficult to diagnose without genetic confirmation. A recently developed pan-TRK antibody shows promise for identifying tumours with NTRK fusions. The aim of this study was to evaluate the utility of pan-TRK immunohistochemistry in distinguishing secretory carcinoma from mimics.

METHODS AND RESULTS

We examined whole-tissue sections from 86 tumours, including 14 secretory carcinomas (12 parotid primaries and one buccal primary, and one metastasis; five with ETV6 rearrangement confirmed by fluorescence in-situ hybridisation, and one with ETV6-NTRK3 fusion and one with ETV6-RET fusion detected by targeted sequencing), 14 acinic cell carcinomas, 18 polymorphous adenocarcinomas, 20 low-grade mucoepidermoid carcinomas, and 20 pleomorphic adenomas. Immunohistochemistry was performed with a pan-TRK rabbit monoclonal antibody. Pan-TRK staining was detected in nine (64%) secretory carcinomas, all with a nuclear pattern and four with diffuse staining (>50% of cells). Among other tumour types, pan-TRK immunoreactivity was observed in all (100%) pleomorphic adenomas (particularly myoepithelial cell-rich, myxoid areas), 15 (83%) polymorphous adenocarcinomas, and four (20%) low-grade mucoepidermoid carcinomas, all with predominantly membranous/cytoplasmic immunoreactivity; only six cases showed focal (<10%) nuclear staining. All acinic cell carcinomas were entirely negative.

CONCLUSIONS

Although pan-TRK expression is not entirely sensitive or specific for secretory carcinoma, nuclear staining distinguishes secretory carcinoma from mimics. Acinic cell carcinomas are negative for pan-TRK, though membranous expression of TRK is common in other salivary gland neoplasms. The lack of pan-TRK immunoreactivity in a subset of secretory carcinomas may suggest non-NTRK fusion partners.