SalvGlandDx - a comprehensive salivary gland neoplasm specific next generation sequencing panel to facilitate diagnosis and identify therapeutic targets

Diagnosis of salivary gland neoplasms is often challenging due to their high morphological diversity and overlaps. Several recurrent molecular alterations have been described recently, which can serve as powerful diagnostic tools and potential therapeutic targets (e.g. NTRK or RET fusions). However, current sequential molecular testing can be expensive and time consuming. In order to facilitate the diagnosis of salivary gland neoplasms, we designed an all-in-one RNA-based next generation sequencing panel suitable for the detection of mutations, fusions and gene expression levels (including NR4A3) of 27 genes involved in salivary gland neoplasms. Here we present the validation of the "SalvGlandDx" panel on FFPE histological specimen including fine needle aspiration (FNA) cell block material, against the standard methods currently used at our institution. In a second part we describe selected unique cases in which the SalvGlandDx panel allowed proper diagnosis and new insights into special molecular characteristics of selected salivary gland tumors. We characterize a unique salivary gland adenocarcinoma harboring a ZCCHC7-NTRK2 fusion, a highly uncommon spindle cell and pseudoangiomatoid adenoid-cystic carcinoma with MYBL1-NFIB fusion, and a purely oncocytic mucoepidermoid carcinoma, whereas diagnosis could be made by detection of a CRTC3-MAML2 rearrangement on the cell block specimen of the FNA. Further, a rare case of a SS18-ZBTB7A rearranged low-grade adenocarcinoma previously described as potential spectrum of microsecretory adenocarcinoma, is reported. In addition, features of six cases within the spectrum of polymorphous adenocarcinoma / cribriform adenocarcinoma of salivary gland including PRKD1 p.E710D mutations and novel fusions involving PRKAR2A-PRKD1, SNX9-PRKD1 and ATL2-PRKD3, are described.

Treatment outcomes in metastatic and localized high-grade salivary gland cancer: high chance of cure with surgery and post-operative radiation in T1-2 N0 high-grade salivary gland cancer

BACKGROUND

High-grade salivary gland cancer is a distinct clinical entity that has aggressive disease progression and early systemic spread. However, because of the rarity of the disease, the clinical outcomes, prognostic factors and clinical decision on the optimal treatments have not been fully understood.

METHODS

In this study, we retrospectively analyzed the clinical data of 124 patients with high-grade salivary gland cancers and performed multivariate survival analyses to evaluate the clinico-pathological factors affecting the treatment outcomes.

RESULTS

The 5-year disease-specific survival was 63.4% in patients with high-grade salivary gland cancers. Among the clinico-pathological factors, presence of lymph node metastasis (hazard ratio 5.63, 95% confidence interval 2.64-12.03, P < 0.001) and distant metastasis (hazard ratio 4.59, 95% confidence interval 2.10-10.04, P < 0.001) at diagnosis were the most potent unfavorable prognostic factors. Importantly, patients with early-stage disease (T1-2N0M0) showed apparently a relatively excellent prognosis (93.2% 5-year disease-specific survival); meanwhile N (+) and M1 status at diagnosis resulted in dismal outcomes (44.6 and 21.1% 5-year disease-specific survival, respectively). On comparing surgery alone as a treatment modality, surgery plus postoperative radiation significantly benefited the patients, but the difference between adjuvant radiation and chemoradiation was not found to be significant. Pathological subtypes of high-grade salivary gland cancers were not significantly associated with prognosis.

CONCLUSIONS

Despite of an overall unfavorable prognosis in high-grade salivary gland cancer, patients with early-stage disease are expected to have excellent prognosis (over 90% survival rates) with surgery plus adjuvant radiation, which may implicate the patients' consultation, therapeutic decision making, and the need for early detection of the disease.

Biomarker immunoprofile and molecular characteristics in salivary duct carcinoma: clinicopathological and prognostic implications

Salivary duct carcinoma (SDC) is one of the most aggressive salivary gland tumors, and prognosis remains poor for most patients. The aim of this study was to investigate the prognostic implications of biomarker immunoprofile in a cohort of SDC and to identify molecular characteristics through next-generation sequencing (NGS) in a subset of cases. Clinicopathological and follow-up information of 25 cases diagnosed as SDC was collected. Immunoexpression of AR, HER-2/neu, GATA3, CK5/6, and MIB1 was analyzed, and ERBB2 (HER-2/Neu) gene amplification was investigated by fluorescence in situ hybridization. Cases were classified under the "SDC revised classification system." Eight SDC cases were analyzed by targeted NGS for detection of gene fusions and variants. Overall survival and disease-free survival were analyzed with Kaplan-Meier curves and Cox regression. Most cases expressed AR (100%), GATA3 (73%), and CK5/6 (76.5%), and 42% expressed HER-2/neu. ERBB2 gene amplification was proven by fluorescence in situ hybridization in 7 of 15 (46%) cases. Apocrine HER2 (AR+/HER2+) subtype was significantly associated with lower overall survival (P = .05). NGS analysis revealed 9 pathogenic mutations in 7 SDC cases, and the most frequently mutated gene was HRAS (4/9) followed by PIK3CA (2/9) and TP53 (2/9). One case (1/9) presented homozygous deletion of locus 9p21 (CDKN2A), and another case (1/9) showed MDM2 amplification. In conclusion, we demonstrated that Apocrine HER2 (AR+/HER2+) is a potential biomarker of poor outcome in SDC. Furthermore, NGS analysis revealed recurrent mutations in SDC.

Pathologic grading of mucoepidermoid carcinomas of the salivary gland and its effect on clinicopathologic follow-up: an institutional experience

Mucoepidermoid carcinoma (MEC) is the most common malignant salivary gland tumor. Differences inprognosis can be noted owing to the tumor grade determined using multiple grading schemes (2-tier: low- and high-grade vs. 3-tier: low-, intermediate-, and high-grade). We studied clinicopathologic features of MEC using a 3-tier grading system and retrospectively categorized cytologic diagnoses as per the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC).A total of 69 cases of MEC were identified, and most were seen in the parotid gland. Aggressive clinical behavior was seen in high-grade MEC compared with intermediate- and low-grade MEC. By fluorescence in situ hybridization (FISH) analysis, MAML2 rearrangements were seen in 78% of cases.The MSRSGC subcategorized the majority (63.8%) of MEC as salivary gland neoplasm of uncertain malignant potential, suspicious for malignancy, or malignant. Clustering intermediate- with low-grade cases did not significantly impact the clinical behavior. Both high-grade and oncocytic MEC can be MAML2 FISH negative.

Hyalinizing Clear Cell Carcinoma of the Bronchus

Hyalinizing clear cell carcinoma (HCCC) is an uncommon low-grade minor salivary gland neoplasm that usually arises in the head and neck region. We report a 55-year-old man who presented with a 2.5 cm lung mass that was partially obstructing the right bronchus intermedius. The tumor consisted of cords and nests of clear and eosinophilic cells in a hyalinized stromal background. The neoplastic cells expressed cytokeratin (CK) 7, CK 5/6, high-molecular weight cytokeratin (34BE12), p63 and p40, while TTF-1, napsin A, CK20, S100, smooth muscle actin, synaptophysin and chromogranin were negative. Mucicarmine stain also was negative in the lesional cells. Fluorescence in situ hybridization using break apart probes revealed rearrangement of the Ewing Sarcoma Breakpoint Region 1 gene locus. The morphologic, immunophenotypic and cytogenetic findings confirmed the diagnosis of HCCC, most likely of bronchial submucosal gland origin. To our knowledge, only two other reports of primary pulmonary HCCC are available in English literature.

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

Sialadenoma papilliferum (SP) is a rare benign salivary gland neoplasm that comprises from 0.4 to 1.2% of all salivary gland tumors. The tumor is so named because of its microscopic resemblance to the syringocystadenoma papilliferum, an uncommon benign tumor of sweat gland origin. The purpose of this paper is to report the clinical and microscopic features of seven new cases of SP and combine them with cases previously reported in the English language literature to further define this unusual lesion. Combining our cases with acceptable cases from the literature, the palate (especially the hard palate) was the most common site, with 80% of the cases occurring in this location. Other locations in decreasing order were buccal mucosa, upper lip, retromolar pad, and parotid gland. Age at diagnosis ranged from 18 to 87 years with a peak in the 6th decade and an average age of 56.4 years. Microscopically, the lesions demonstrated a papillary surface morphology, and the papillary projections varied from long and pointed to short and blunted. The supporting connective tissue contained a variable number of convoluted ductal structures, which often fused with the overlying surface epithelium. The ductal structures exhibited papillary infoldings and were lined by a double layer of epithelium consisting of basal cell layer and a luminal layer of cuboidal-to-columnar ductal cells. Immunohistochemical reactivity with p63 and p40 indicated that the basal cell layer was comprised predominantly of neoplastic myoepithelial cells. The luminal cells were immunoreactive with epithelial membrane antigen characteristic of ductal cell differentiation. Conservative surgical treatment was accomplished in most cases and appears to be adequate treatment as only two recurrences were documented. Several case reports of purported malignant transformation in SP have been reported in the literature, but in our opinion, there is insufficient evidence in the publications to unequivocally determine whether any of the malignancies truly originated within a pre-existing SP.

Milan Interobserver Reproducibility Study (MIRST): Milan System 2018

INTRODUCTION

Prior to the 2018 publication of the Milan System for Reporting Salivary Gland Cytopathology (MSRSGC), a Web-based interobserver study was performed to evaluate MSRSGC reporting categories, identify cytomorphologic features that represent poor sources of agreement, and establish a baseline for future studies.

MATERIAL AND METHODS

Study participants evaluated 75 images chosen from the MSRSGC image set, prior to the release of the Milan Atlas. Images spanned all diagnostic categories including typical and borderline cytomorphology. Participant demographics were collected on level of training, practice patterns, and experience.

RESULTS

A total of 647 persons attempted access to the survey. Of these, 555 correctly answered the qualifying questions. Participants included: 16.5% ASCP Certified Cytotechnologists, 2.8% Specialist Cytotechnologists, 5.8% IAC Certified individuals, 14.3% Anatomic (AP) Certified Pathologists, 38.9% AP and Cytopathology Certified Pathologists, and 15.3% pathology trainees. Length of participant practice varied from 0 to 54 years. In our sample, 43.4% of participants came from academic centers, 17.6% from private hospitals; and 13.3% from commercial/private laboratories. Overall, 42% of respondents agreed with the reference interpretations of salivary gland lesions. The best agreement was seen in cytopathology certified pathologists. Among the MSRSGC categories, best agreement was found in Neoplasm-Benign (58.9%) and Non-Diagnostic (49.2%) categories, followed by Malignant (48.4%). The agreement rates for Salivary Gland Lesion of Uncertain Malignant Potential (SUMP) and Suspicious For Malignancy (SFM) were 23.6% and 22.7%, respectively.

CONCLUSIONS

Similar to the reproducibility studies conducted for gynecologic and urinary cytopathology, the most important factor in diagnostic reproducibility was a priori classification of image difficulty, although people with higher certifications performed better.

The Value of F-18 FDG PET for Planning Treatment and Detecting Recurrence in Malignant Salivary Gland Tumors: Comparison with Conventional Imaging Studies

PURPOSE

To assess the value of F-18 FDG PET/CT for detecting cervical lymph node (LN) metastasis and recurrence, as well as planning treatment, and to compare the accuracy of PET/CT with conventional imaging studies (CIS) in patients with malignant salivary gland tumor (SGT).

METHODS

Staging and follow-up PET/CT for SGT were retrospectively reviewed. Enhanced CT and/or MRI of the neck were performed within 1 month of PET/CT. Final diagnosis was based on histology from cervical LN dissection and biopsy or a minimum 6 months of clinical and imaging follow-up. We compared the performance of PET/CT in initial cervical LN staging and recurrence detection with that of CIS.

RESULTS

A total of 184 PET/CT exams of 66 patients were included, and 34 initial staging and 150 surveillance PET/CT exams were performed. The initial cervical LN detection sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 60.9 %, 89.2 %, 84.0 %, 56.0 %, and 91.0 % for visual analysis on PET/CT, 39.1 %, 95.0 %, 84.8 %, 64.3 %, and 87.4 % for semiquantitative analysis on PET/CT, and and 43.5 %, 94.1 %, 84.8 %, 62.5 %, and 88.1 % for CIS. The sensitivity of visual analysis on PET/CT was significantly higher than that of semiquantitative analysis on PET/CT and CIS (p = 0.0009 and 0.0086). In 5 of 34 initial staging patients (14.7 %), the treatment plan was changed from curative surgery to palliative therapy. The performance of follow-up PET/CT showed no significant difference compared with CIS.

CONCLUSION

PET/CT showed comparable performance with CIS for cervical LNs staging. Initial PET/CT changed treatment plans in 14.7 % of patients. However, PET/CT offered no additional advantage for detecting locoregional recurrence.

Polymorphous adenocarcinoma of salivary glands

OBJECTIVE

Polymorphous adenocarcinoma of salivary gland (PAC) is rare. Despite being described as a low risk histology, some patients develop regional and distant metastasis. More aggressive behavior has been attributed to a PAC subcategory called cribriform adenocarcinoma of minor salivary glands (CAMSG). We examined oncological outcomes of PAC.

PATIENTS AND METHODS

Fifty-seven patients with PAC were identified from an institutional database of 884 patients surgically treated for salivary gland malignancies from 1985 to 2015. Detailed histopathological analysis was performed. Survival outcomes were calculated using the Kaplan-Meier method. Factors predictive of recurrence were identified using the Cox proportional hazard method.

RESULTS

Fifty-four (95%) had tumors of minor salivary gland origin; the most frequent location was the oral cavity in 41 (76%), specifically the hard palate in 32 (55%). Forty-six patients (81%) were clinical T1-T2; 3 (5%) had a clinically positive neck. Thirty-two patients (56%) were classified as PAC and 14 (25%) as CAMSG. Forty-four patients (77%) had surgery alone; 13 (23%) had surgery and postoperative radiotherapy. The 5- and 10-year overall survival and disease-specific survival were 88% and 79% and 98% and 94%, respectively (median follow up 84 [1-159] months); 5- and 10-year recurrence-free survival were 93% and 88%, respectively. Univariate analysis showed male sex, III/IV stage, and CASMG variant had increased incidence of recurrence but were not statistically significant.

CONCLUSION

PAC of the salivary glands is an indolent disease with good survival outcomes. Recurrence is uncommon and tends to occur late. Long-term follow-up is indicated in patients with this disease.

Human Epidermal Growth Factor Receptor 2 (HER2/neu) in Salivary Gland Carcinomas: A Review of Literature

The aim of our study is to assess the relation of human epidermal growth factor receptor 2 or HER2/neu with the development of salivary gland carcinomas and use of Herceptin in the treatment of these cancers. A literature search was conducted using MEDLINE accessed via the National Library of Medicine PubMed interface searching for articles from 1994 up to 2014 relating to the existence of HER-2 protein and gene in salivary gland carcinomas and HER2/neu targeted therapy, written in English language. Almost all the studies in literature reported a frequent over expression and amplification of HER2/nue in salivary duct carcinomas (SDC) compared to other salivary gland cancers. Herceptin given as a monotherapy was not effective. The data on Herceptin combined chemotherapy are potentially promising but inadequate to evaluate drug activity, as patients also received a variety of cytotoxic agents. Therefore, Herceptin contribution to tumour response outcomes could not be precisely determined and the total number of cases is not sufficient. It is recommended that further work involves a large series of HER2/neu positive salivary gland cancers (randomized control trial) treated with chemotherapy with and without Herceptin. This might need multi-institutional cooperation.

Low Grade Carcinoma Ex-Pleomorphic Adenoma: Diagnosis and Diagnostic Challenges Caused by Fine Needle Aspiration: Report of Three Cases and Review of Literature

Low grade carcinoma ex pleomorphic adenoma (LG CXPA) is a rare low grade malignant neoplasm arising from preexisting pleomorphic adenoma (PA). LG CXPA demonstrates no overt cytological atypia, and can be difficult to distinguish from cellular PA. Invasive growth is one of the hallmarks of LG CXPA, e.g., tumor extends beyond the capsule and into adjacent non-neoplastic tissue. However, it is known that capsular and vascular invasion, as well as the presence of stroma-rich PA in soft tissue without a capsule (pseudopodia) can be seen in PA. These histological findings have no prognostic significance and are not diagnostic of malignancy. In addition, recurrent PA typically presents as numerous nodules extending into soft tissue and skeletal muscle, which again are not considered malignant features. Thus, "infiltrative growth" of LG CXPA is difficult to define and diagnosis is challenging to many practicing pathologists. In this study, we report three cases of LG CXPA. We review the diagnostic criteria for LG CXPA, and discuss the diagnostic challenges caused by fine needle aspiration (FNA) changes. FNA is widely used as a cost-effective, quick and accurate method for diagnosing salivary gland lesions. Histological changes post-FNA are usually focal and mild, and are not causes of diagnostic difficulties. According to our knowledge, this is the first report of LG CXPA complicated with FNA changes.

Osteoradionecrosis in patients with salivary gland malignancies

PURPOSE

The present study was undertaken to evaluate osteoradionecrosis (ORN) in patients with salivary gland malignancies (SGM) after treatment with radiation therapy.

MATERIALS AND METHODS

The medical records of 172 patients treated with radiation therapy for SGM during a 12-year period (August 2001 to November 2013) were reviewed. Incidence, time to event, staging and management of ORN were analyzed.

RESULTS

Of the 172 patients, 7 patients (4%) developed ORN (median latency: 19months, range: 4-72months). Of those 7 patients, 4 required major surgery, 1 required hyperbaric oxygen therapy (HBO), one required minor debridement, and one required conservative management. Total prescribed radiation dose varied from 50Gy (1 case) to 70Gy (1 case) among those patients who developed ORN, and radiotherapy was delivered postoperatively after osseous resection in 4 of 7 cases. Three of the 7 cases of ORN occurred after traumatic injury to the bone. Of the 7 patients who developed ORN, 3 had SGM of the major glands, 3 had other sites of the oral cavity, and 1 had a sinonasal location.

CONCLUSION

While the rate of ORN after radiotherapy for SGM was somewhat lower (4%) than previously published data on patients with squamous cell carcinomas of the head and neck treated with radiation therapy (8-14%), ORN necessitating major surgery remains a clinically significant, possible late effect of radiotherapy in SGM survivors. Location of SGM is very important, with cases that developed ORN disproportionally having primary disease arising in the oral cavity.

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

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

Central papillary cystadenocarcinoma of the mandible: A case report and review of the literature

INTRODUCTION

Central papillary cystadenocarcinoma of the jaw is an extremely rare tumor with only three previously reported cases in the English literature. This tumor is a histologically low-grade cancer, affecting more commonly in the mandible than in the maxilla.

PRESENTATION OF CASE

A 65-year-old woman presented with a two months history of a rapidly growing, painless mass of the right ascending ramus of the mandible. The pathologic report from incisional biopsy was a papillary cystic tumor with a differential diagnosis of cystadenoma versus cystadenocarcinoma. Segmental mandibulectomy, parotidectomy and submandibular gland resection were performed. The final pathology was intraosseous papillary cystadenocarcinoma.

DISCUSSION

Clinical features of central papillary cystadenocarcinoma of the mandible mimic an odontogenic lesion and metastatic bone disease, careful review of radiograph and pathology should be done. Surgical excision with wide margins is the appropriate treatment. Postoperative radiation therapy should be considered in histologically aggressive or high-stage tumor.

CONCLUSION

This is the fourth case of central papillary cystadenocarcinoma of the mandible in the English literature. Although it is usually a low-grade cancer, en bloc resection with adjuvant postoperative radiotherapy in a high-stage disease, and long-term follow-up allow the patient to have a favorable prognosis.

Salivary gland tumors: a diagnostic dilemma!

Salivary gland tumors generate considerable interest because of their heterogeneous and variable histology, grade of malignancy, and clinical behavior. Fine needle aspiration cytology (FNAC) is considered the first diagnostic modality for salivary neoplasms due to its ready availability and ease of performance. However it cannot always be relied upon in isolation, and should be used in conjunction with other investigations like incisional biopsy. We present two cases, which highlight the drawbacks of relying on FNAC alone, which resulted in misdiagnosis of adenoid cystic carcinoma as pleomorphic adenoma.

Sex disparities in salivary malignancies: Does female sex impact oncological outcome?

OBJECTIVE

Previous population-based studies in salivary gland carcinomas have described a relationship between female sex and superior oncological outcome.

PATIENTS AND METHODS

Our institutional database of 884 surgically treated patients with salivary gland malignancies from 1985 to 2015 was analyzed for the impact of sex on oncological outcomes. Histologies were classified in three risk groups, low, intermediate and high. Survival outcomes were determined using the Kaplan-Meier method. Hazard ratios for male sex were determined using the Cox proportional hazards model.

RESULTS

Eight hundred sixty-seven patients were identified; median age was 59 years, and 51% had a minor salivary gland malignancy. Female patients were younger (58 versus 60 years; p = 0.040) and had a lower incidence of high-risk histologies (25% versus 40%, p < 0.001) and T3-T4 tumors compared to men (23% versus 31%, p < 0.001). With a median follow-up of 57 months, female patients had a superior 5-year disease-specific survival (DSS) (90% versus 79%; p < 0.001). The unadjusted hazard ratio showed male patients had a 2.15-fold increased risk of death (HR 2.15; 95% CI, 1.50-3.06, p < 0.001). After adjusting for Charlson comorbidity index, tobacco use, histological risk group, and overall pathological stage, males still had a statistically significant increased risk of death (HR 1.48; 95% CI 1.05-2.17; p = 0.047). Subgroup analysis showed DSS for females was significantly better in the high-risk histological group (5-year 68% versus 49%, p = 0.007).

CONCLUSION

Our study shows that sex has an impact on cancer-specific survival and that female sex favors improved survival.

Diagnostic utility of C-kit protein (CD117) expression in differentiating adenoid cystic carcinoma and polymorphous low grade Adenocarcinoma

Background & Objective:

To evaluate usefulness of immunohistochemical marker C-kit (CD117) in differentiating Adenoid cystic carcinoma (AdCC) from Polymorphous low-grade adenocarcinoma (PLGA) in patients of salivary gland carcinomas. AdCC is a malignant salivary gland neoplasm with poor prognosis. PLGA is a salivary gland malignancy with indolent growth pattern. Differentiating between the two entities is a diagnostic challenge. We evaluated the role of C-kit in differentiating the two.

Methods:

This is a Cross sectional study. Samples of 19 tumors including 12 AdCC and 4 PLGA was evaluated at Department of Histopathology, Armed Forces Institute of Pathology, Rawalpindi from December 2015 to August 2016. Immunohistochemical techniques were used to analyze the level of c-kit expression in AdCC (n = 12), polymorphous low-grade adenocarcinoma (PLGA) (n = 6). Samples were stained using monoclonal antibody against C-kit. Statistical analysis of the data was done using SPSS version 21.

Results:

Strong diffuse cytoplasmic reactivity was observed in more than 50% of the tumor cells of AdCC whereas less than 20% of cells showed negative to weak positivity in PLGA. Hence, the difference in the expression of c-kit between AdCC and PLGA was statistically significant (p value <0.002).

Conclusions:

CD117 expression itself can be used as a marker in differential diagnosis of salivary gland neoplasms. However, the percentage of the CD117 immunoreactive cells and the staining intensities appeared to be important factors in distinguishing AdCC from PLGA.

Nectin-4 is frequently expressed in primary salivary gland cancer and corresponding lymph node metastases and represents an important treatment-related biomarker

Many locally advanced and metastatic salivary gland carcinomas (SGC) lack therapeutic targets. Enfortumab vedotin, an antibody-drug conjugate binding to Nectin-4, recently gained FDA approval for third-line urothelial carcinoma. Therefore, the aim of this study was to assess the expression of Nectin-4 in primary SGC and corresponding lymph node metastases and to correlate it with clinicopathological data. Immunohistochemical staining for Nectin-4 was performed for patients who had undergone surgery with curative intent for primary SGC of the parotid or submandibular gland in a tertiary referral center between 1990 and 2019. One hundred twenty-two primary SGC and twenty corresponding lymph node metastases were included. Nectin-4 was expressed in 80.3% of primary SGC with a mean Histo(H-)score of 61.2 and in 90.0% of lymph node metastases with a mean H-score of 75.6. A moderate or high Nectin-4 expression was found in 25.9% of salivary duct carcinomas (SaDu) and in 30.7% of adenoid cystic carcinomas (ACC). SaDu patients with a lower T-stage (p = 0.04), no loco-regional lymph node metastases (p = 0.049), no vascular invasion (p = 0.04), and no perineural spread (p = 0.03) showed a significantly higher mean Nectin-4 H-score. There was a statistical tendency towards a more favorable disease-free survival among SaDu patients with a higher Nectin-4 expression (p = 0.09). Nectin-4 is expressed in SGC and therefore represents a potential therapeutic target, especially in entities with a high rate of local recurrence and metastatic spread such as SaDu and ACC.

Endoscopic trans-pterygoid resection of a low-grade cribriform cystadenocarcinoma of the infratemporal fossa

This article presents a case of low-grade cribriform cystadenocarcinomas (LGCCC), a rare salivary gland tumor manifesting in the infratemporal fossa (ITF). The lesion in this case is unique in its location, histopathology, and management in that the tumor resection was performed using an exclusively endoscopic, endonasal approach. This case highlights the expanding application of endoscopic skull base techniques to address an indolent, slow-growing malignancy of the ITF.

PLAG1 enhances the stemness profiles of acinar cells in normal human salivary glands in a cell type-specific manner

OBJECTIVES

Details of the histogenesis of salivary gland tumors are largely unknown. The oncogenic role of PLAG1 in the salivary gland has been demonstrated in vivo. Herein, we demonstrate PLAG1 roles in the acinar and ductal cells of normal human salivary glands to clarify the early events that occur during the histogenesis of salivary gland tumors.

METHODS

Normal salivary gland cells with acinar and ductal phenotypes were transfected with PLAG1 plasmid DNA. Subsequently, PLAG1 overexpressed and mock cells were examined by cell proliferation, transwell migration, and salisphere formation assays. Differentiation and salivary and pluripotent stem cell marker expression levels were evaluated by quantitative reverse transcription-polymerase chain reaction and immunofluorescence. Alterations in transcriptional expressions were investigated via cap analysis of gene expression with gene-enrichment and functional annotation analysis.

RESULTS

PLAG1 promoted cell proliferation and transwell migration in the acinar and ductal cells, and markedly enhanced the stemness profiles and luminal cell-like profiles in acinar cells; the stemness profiles were partially increased in the ductal cells.

CONCLUSION

PLAG1 enhanced the stemness profiles in the acinar cells of normal human salivary glands in a cell type-specific manner. Thus, it may be involved in salivary gland tumorigenesis by increasing the stemness character of the normal salivary gland cells.

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.

An extremely rare salivary gland tumor: intraductal carcinoma of the buccal mucosa

Intraductal carcinoma of the salivary gland is a rare, indolent neoplasm characterized by intraductal malignant cell proliferation but lacking invasiveness, in contrast to conventional salivary duct carcinoma, a clinically aggressive neoplasm with invasive characteristics. The tumor affects the major salivary glands much more frequently than the minor salivary glands. This report describes an extremely rare intraductal carcinoma arising from the buccal mucosa in a 61-year-old man who presented with a painless mass in the left buccal mucosa, which he had had for 1 month. A biopsy of the tumor indicated it was most likely an adenocarcinoma, but accurate preoperative diagnosis was difficult. The tumor was completely removed, along with sufficient margins. Histological examination revealed that the lesion was composed of proliferating epithelial cells surrounded by an intact myoepithelial layer, with no evidence of invasion. The final diagnosis was intraductal carcinoma of the salivary gland. No recurrence has been observed for over 3 years. In conclusion, the difficulty in preoperatively diagnosing this rare entity suggests that complete surgical excision with sufficient margins remains the best treatment option.

Pleomorphic Adenoma in Retromolar Area: A Very Rare Case Report and Review of Literature

Among all neoplasms affecting head and neck region, salivary gland neoplasms are rare. Pleomorphic adenomas are the most common benign salivary gland tumours making up to 50% of major and minor salivary gland tumours. Intraorally pleomorphic adenoma is mostly found on palate and lips and very rarely in retromolar area. Here we are reporting a rare case of pleomorphic adenoma in right lower retromolar area in a 31-year-old female, the lesion was excised in toto with safety margins under local anaesthesia and postoperative follow up after six months didn't showed any recurrence.

Loss of BAP1 Protein Expression by Immunohistochemistry in the Salivary Duct Carcinoma Component of an Intracapsular Carcinoma ex Pleomorphic Adenoma of the Parotid Gland

BACKGROUND

BRCA1-associated protein 1 (BAP1) is a tumor suppressor gene that is altered in a variety of neoplasms as well as in BAP1 tumor predisposition syndrome. BAP1 alterations are associated with aggressive behavior in some malignancies and may have treatment implications in future. We present the first documented case of loss of BAP1 protein expression by immunohistochemistry in the salivary duct carcinoma (SDC) component of an intracapsular carcinoma ex pleomorphic adenoma (CXPA) in the context of molecular loss of function of BAP1 in the neoplasm.

METHODS

A woman of approximately 55 years of age presented with a deep parotid lobe mass, which was resected and found to be CXPA. BAP1 immunohistochemistry and next-generation sequencing was performed to further characterize the neoplasm.

RESULTS

The neoplasm showed loss of BAP1 protein expression in the SDC component but retention in the residual pleomorphic adenoma (PA). Next-generation sequencing confirmed a BAP1 loss of function alteration in the neoplasm.

CONCLUSION

This is the first documented case report of BAP1 protein expression loss in the SDC component of a CXPA. Future studies are needed to investigate the relevance of BAP1 alterations in SDC and CXPA, which may have prognostic and treatment implications.

Occult nodal metastasis in major salivary gland malignancy: An update from the National Cancer Database

OBJECTIVES

Malignant salivary gland tumors are rare neoplasms that are vastly heterogenous in their histological patterns and clinical behaviors. As a consequence, studies have lacked the robust sample sizes needed to define treatment strategies. In this study, we used the National Cancer Database to identify the incidence of occult nodal metastasis and effect on overall survival for the most common malignant salivary gland subtypes. A retrospective review of patients in the National Cancer Database with primary site malignancies of major salivary glands between 2004 and 2016 was performed. Subjects included in the study underwent surgical treatment with and without adjuvant radiation and had complete information on TNM pathological stage.

MATERIALS AND METHODS

8,689 patients with primary malignant salivary gland cancer were analyzed. The sample was stratified by histologic subtype. Univariate analysis of lymph node metastasis of the whole cohort showed a higher risk of death (p < 0.001), when compared to those without. Also when comparing occult vs evident metastasis, the risk of death was higher for the latter (p < 0.001).

RESULTS AND CONCLUSION

Occult cervical lymph node metastasis ranged from 14.9% to 35.8% in malignant salivary gland cancers, depending on histological subtype. Occult nodal metastasis was a poor prognostic factor with significantly worse overall survival.