Malignant Salivary Gland Tumors Research Articles

Pitfalls in Diagnosis of Myoepithelial Carcinoma of Salivary Glands: A Study of 3 Cases with Cytologic-histologic Correlation and Molecular Analysis.

Myoepithelial carcinoma (MECA) represents < 1% percent of salivary gland (SG) tumors with a mean age of 55 years. These tumors can arise de novo or in association with pre-existing pleomorphic Adenoma (PA). The cytologic features of MECA overlap with other SG neoplasms including the more common benign entities like PA and myoepithelioma and can pose a diagnostic challenge. A database search for MECA was performed spanning 10 years. 3 cases qualified with available cyto-histologic correlation. All were morphologically MECA with one case diagnosed as MECA ex-PA. The cases were subjected to a comprehensive immunohistochemical and molecular evaluation (Case#1 has been previously reported and published in head and neck pathology in 2021). A comparative analysis of these cases is presented in Table1. All three cases were initially diagnosed as PA on cytology. On review of cytology slides, presence of metachromatic stromal fragments and bland myoepithelial cells was found to be the most common diagnostic pitfall. S100 was positive in all cases while myosin, p63, and GFAP were variably positive. Molecular analysis revealed novel, previously undescribed mutations in the three cases. Additionally, two of three cases expressed PD-L1, suggesting a role for immunotherapy in treatment. Cytomorphology of MECA is poorly described in literature and can pose a diagnostic challenge due to overlapping features with salivary gland benign neoplasms. A conclusive diagnosis on cytology is often not possible. However, a high cellularity, predominant oncocytoid/ myoepithelial cell population on smears and cell block, along with a strong clinical and radiologic suspicion for malignant salivary gland tumor, should alert the cytopathologist and help avoid an erroneous benign diagnosis on cytology.

A Case Series of a Rare Parotid Gland Oncocytic Mucoepidermoid Carcinoma

Abstract Introduction/Objective We analyzed two cases of oncocytic mucoepidermoid carcinoma (OMEC) of the parotid gland which highlight the diagnostic challenges of oncocytic salivary gland neoplasms. OMEC’s are a rare type of salivary gland tumor commonly arising from the parotid gland that can easily be mistaken as benign. Proper pathologic diagnosis of these masses is critical, as it guides therapeutic intervention and has prognostic significance. Methods/Case Report In this case series, two patients were analyzed retrospectively for unilateral parotid masses. Results (if a Case Study enter NA) In a 67-year-old female, an MRI and biopsy were performed. Only a differential diagnosis could be provided, which favored oncocytoma or oncocytic carcinoma. Due to this uncertainty, a complete excision of the mass was performed. Considering the cytomorphology, immunohistochemistry (CK5/6 and P63 in oncocytes), and mucicarmine special stain highlighting scattered mucocytes, the patient was diagnosed with a low- grade OMEC. In our second case, an 80-year-old female, FNA of a posterior left ear mass 1 year prior revealed a low- grade oncocytic proliferation. With the presence of a left parotid mass one year later, additional imaging was performed and showed increased T2 hyperintensity on MRI, which caused concern for the clinicians. A superficial limited parotidectomy was performed and a differential of oncocytoma versus oncocytic variant of mucoepidermoid carcinoma was rendered. Further tumor characterization with fluorescence in situ hybridization (FISH) demonstrated a MAML2 translocation which guided diagnosis of OMEC. Conclusion With approximately 30% of all malignant salivary gland tumors being constituted by mucoepidermoid carcinoma, the ability to accurately diagnose even this rare subtype, oncocytic mucoepidermoid carcinoma, is of significant importance and relevance to pathologists in many practice settings. Herein we demonstrate the utility of H&amp;E morphology, immunohistochemistry, and MAML2 FISH in diagnosing OMEC in the setting of oncocytic salivary gland lesions. Future avenues, including tumor molecular profiling, will aid in elucidating clinicopathologic characteristics of this entity.

Bronchial Sialadenoma Papilliferum in a 10-Year-Old Boy.

Sialadenoma papilliferum (SP) is a rare salivary gland tumor mostly reported in the oral cavity. Here we describe a bronchial SP in the left upper lobe bronchus of a 10-year-old boy. At bronchoscopy, a well-circumscribed polypoid lesion protruding into the bronchial lumen was identified. The tumor was excised, but eventually, the patient had to undergo a sleeve resection after 2 recurrences. Pathology revealed a papillocystic lesion with exophytic and endophytic components. The cells lining the exophytic surface and papillary structures were columnar and squamous, and the cells lining endophytic cystic and papillary structures were cuboidal to columnar, all of which were diffusely reactive with antibodies to SOX10 protein. The presence of basal cells was demonstrated by p63 immunoreactivity. The cells failed to immunohistochemically express BRAF V600E. Fluorescence in situ hybridization analysis revealed no MAML2 or RET gene rearrangement. The patient is alive 24 years after resection with no additional recurrences. Bronchial SP needs to be recognized and distinguished from other benign and malignant salivary gland and pulmonary neoplasms so that patients can receive appropriate treatment and follow-up.

Perplexing Intraoral Swellings: A Cross-Sectional Study On Minor Malignant Salivary Gland Tumors

Background: This study aims to assess the prevalence and correlation between age, gender, and site of malignant minor salivary gland tumors among patients attending a tertiary healthcare centre in Trivandrum from 2015 to 2022. A total of 26 cases were reviewed, with mucoepidermoid carcinoma (MEC) being the most prevalent, followed by adenoid cystic carcinoma (ACC) and polymorphous adenocarcinoma (PAC). Our findings suggest a slight female predilection overall, though certain tumor types showed gender-specific trends. The study highlights important epidemiological insights that can help future research and clinical practice inmanaging malignant minor salivary gland tumors.

COMPARISON OF IMMUNOHISTOCHEMICAL EXPRESSION OF INSULIN LIKE GROWTH FACTOR 1 RECEPTOR (IGF-1R) IN BENIGN AND MALIGNANT SALIVARY GLAND TUMORS

Objectives: To evaluate the difference in immunohistochemical expression of insulin-like growth factor-1 receptor (IGF-1R) in diagnosed cases of benign and malignant salivary gland tumors.Materials and Methods: This Comparative Cross-Sectional Study was conducted at the department of Pathology, Peshawar Medical and Dental College, Peshawar. A total of 100 Salivary Gland Tumors from 56 male and 44 female patients were included in the study, with an average age of 43.50 ± 15.21. The Immunohistochemical Expression of Insulin-like Growth Factor 1 Receptor was determined on both benign and malignant salivary gland tumors using the Bio SB Polyclonal IGF-1R antibody (rabbit, BT-AP04398). The collected data were analyzed using SPSS version 25.Results: For the immunohistochemical expression of IGF-1R on benign and malignant salivary gland tumors, the Allred Scoring method was utilized. P value of &lt;0.05 was considered significant, but no positive signifi cance was found between the expression of IGF-1R and salivary gland tumors.Conclusion: IGF1R expression was positive in various SGTs but no statistically significant difference was seen in multiple histopathological types of benign and malignant SGT

Machine Learning on Ultrasound Texture Analysis Data for Characterizing of Salivary Glandular Tumors: A Feasibility Study.

Objective quantitative texture characteristics may be helpful in salivary glandular tumor differential diagnosis. This study uses machine learning (ML) to explore and validate the performance of ultrasound (US) texture features in diagnosing salivary glandular tumors. 122 patients with salivary glandular tumors, including 71 benign and 51 malignant tumors, are enrolled. Representative brightness mode US pictures are selected for further Gray Level Co-occurrence Matrix (GLCM) texture analysis. We use a t-test to test the significance and use the receiver operating characteristic curve method to find the optimal cut-point for these significant features. After splitting 80% of the data into a training set and 20% data into a testing set, we use five machine learning models, k-nearest Neighbors (kNN), Naïve Bayes, Logistic regression, Artificial Neural Networks (ANNs) and supportive vector machine (SVM), to explore and validate the performance of US GLCM texture features in diagnosing salivary glandular tumors. This study includes 49 female and 73 male patients, with a mean age of 53 years old, ranging from 21 to 93. We find that six GLCM texture features (contrast, inverse difference movement, entropy, dissimilarity, inverse difference and difference entropy) are significantly different between benign and malignant tumors (p < 0.05). In ML, the overall accuracy rates are 74.3% (95%CI: 59.8-88.8%), 94.3% (86.6-100%), 72% (54-89%), 84% (69.5-97.3%) and 73.5% (58.7-88.4%) for kNN, Naïve Bayes, Logistic regression, a one-node ANN and SVM, respectively. US texture analysis with ML has potential as an objective and valuable tool to make a differential diagnosis between benign and malignant salivary gland tumors.

Update of newly-recognized salivary gland neoplasms: molecular and immunohistochemical findings and clinical importance.

With the advancement of molecular testing and the routine use of immunohistochemical stains, salivary gland tumours previously categorized as adenoma or adenocarcinoma, not otherwise specified, are being reclassified with distinct diagnoses. Newly recognized benign entities include: sclerosing polycystic adenoma, keratocystoma, intercalated duct hyperplasia and adenoma, and striated duct adenoma. Newly recognized malignant salivary gland tumours include: microsecretory adenocarcinoma, sclerosing microcytic adenocarcinoma, and mucinous adenocarcinoma. Additionally, rare subtypes of mucoepidermoid carcinoma have been described, including Warthin-like and oncocytic. Understanding of intraductal carcinoma continues to evolve. Correctly distinguishing these lesions from mimickers can be crucial for appropriate patient care and prognostication, as well as future conceptualization of salivary disease.

A rare case of an aggressive polymorphous adenocarcinoma of minor salivary gland in the retro-maxilla

Abstract Polymorphous adenocarcinoma (PAC) is a low-grade malignant tumour of minor salivary glands of the oral cavity, which rarely presents with invasive features. Low metastatic and excellent survival rates are some of its favorable features. A 36-year-old woman reported with swelling, pain, and mobility of teeth in the left upper inner cheek region. Contrast enhanced computed tomography (CECT) revealed a large, lobulated, heterogenous mass in the left retro-maxillary region with a few enlarged left cervical lymph nodes (levels IB and II). After surgery, the final histopathology report gave a definitive diagnosis of PAC with certain invasive characteristics – perineural invasion, infiltration into skeletal muscle, and depth of invasion of 10 mm, which recurred in a different location 1.5 years later. A few predictable features of PAC include incidence in elderly women, asymptomatic presentation, occurrence in the posterior hard of soft palate, very low incidence of nodal or distant metastases, perineural spread, skeletal muscle infiltration, and low rates of recurrence with good survival outcomes. However, in our case, the patient appeared to present with a relatively aggressive form of PAC, considering her young age, symptomatic presentation, uncommon anatomic location in the retro-maxilla, cervical nodal metastasis, perineural and skeletal muscle infiltration, and local recurrence within a short period. Although PAC is a low-grade tumour with excellent prognosis, it may occasionally present with invasive characteristics, and early diagnosis and prompt management with strict adherence to post-operative regimens and follow-up is of prime importance to prevent any untoward outcomes.

Clinical Behavior and Molecular Insights of Secretory Carcinoma of Salivary Glands, a Single Center Experience

Objective: the study aimed to characterize the novel entity referred to as secretory carcinoma of the salivary glands. Methods: we comprehensively evaluated 150 patients afflicted by malignant salivary gland tumors who had been under treatment at the University of Verona. Inclusion criteria primarily focused on the availability of paraffin block materials and adequate follow-up data. Subsequently, we conducted a comprehensive Fluorescent In Situ Hybridization (FISH) analysis, utilizing probes targeting NTRK-3, MALM-2, EWRS-1, HER-2, MDM-2, and NTRK1-2. Results: out of the initial cohort, 37 patients met the eligibility criteria for our study. We identified NTRK3 gene rearrangements in four patients (11%), two of whom had mucoepidermoid carcinoma, and the remaining two had acinic cell carcinoma. Notably, none of these patients had initially received a secretory carcinoma diagnosis. The primary treatment approach for all patients entailed surgical parotid gland resection. The overall survival (OS) for patients with NTRK3 rearrangements amounted to 78 months, with a corresponding progression-free survival (PFS) of 73 months. Conclusion: in summary, our case series suggests that secretory carcinomas exhibit a favorable clinical course and underscores the pivotal importance of distinguishing secretory carcinomas from other histological subtypes.

Mucoepidermoid carcinoma: A comparative analysis of histological grading systems

: Salivary gland carcinomas comprise of only 3-5% of all head and neck malignancies. Mucoepidermoid carcinoma (MEC) is the most common malignant salivary gland tumor. The morphologic diversity of MEC can pose diagnostic challenges hence, various histological grading systems have been proposed based on the quantitative and qualitative analysis. This proves to be greatly consequential in the management and prognosis of patients with MEC.To compare histologic grading methods in MEC of major &amp; minor salivary glands.20 histopathologically diagnosed cases of MEC (10 each major &amp; minor salivary gland) will be analysed using following methods: Qualitative Method: 1) Modified Healey 2) Memorial Sloan-Kettering Cancer Center method. Quantitative method: 1) Armed force Institute of Pathology (AFIP) 2) Brandwein method Histological findings were evaluated. In our study AFIP grading system, 50% Cases were classified as low grade, 35% as intermediate grade and 15% as high graded. According to Brandwein grading system20% of cases were categorized as low, 35% cases as intermediate, 45% cases as high grade MEC. Modified Healey grading system of MEC showed 50%, 40%, 10% cases as low, intermediate and high grade MEC respectively. MSKCC grading system revealed as 55%, 30% and 15% cases as low, intermediate and high grade MEC respectively. Our finding indicated that MSKCC grading system was the most favourable histological grading system as percentage of agreement found to be 85%.Careful microscopic examination is the most important parameter in the grading of MEC. This meticulous microscopic examination emerges as the cornerstone in grading MEC. Both MSKCC and Modified Healey grading methods exhibits effectiveness in evaluating MEC. Our finding indicated that Memorial Slon Kettering Cancer Center (MSKCC) was the most favourable histological grading system as percentage of agreement found to be 85%. However, further longer studies are imperative to substantiate this finding and for establish of universally accepted grading system for Mucoepidermoid carcinoma.

MiR-26a and miR-191 are upregulated while PLAG1 and HIF2 are downregulated in pleomorphic adenomas of the salivary glands compared to Warthin tumors.

Salivary gland tumors (SGTs) are a heterogenous group of pathologies, which still represents a challenge regarding differential diagnosis and therapy. Although histological findings govern SGTs management, detection of molecular alterations is emerging as an effective additional tool. The aim of this study was to analyze the relative expression levels of three micro RNAs (miR-26a, miR-26b, and miR-191), and three pro-oncogenic molecular markers (PLAG1, MTDH, and HIF2) in SGTs and normal salivary gland (NSG) tissues and evaluate them as potential differential diagnosis markers. This cross-sectional study included 58 patients with SGTs (23 pleomorphic adenomas, 27 Warthin tumors, and 8 malignant SGTs) and 10 controls (normal salivary gland tissues). Relative gene expression levels of all investigated molecules were determined by reverse transcriptase-real-time polymerase chain reaction. All three micro RNAs exhibited highest expression levels in benign SGTs, whereas miR-26a And miR-191 were significantly more expressed in PAs compared to WTs (p = 0.045 and p = 0.029, respectively). PLAG1 And HIF2 were both overexpressed in WTs compared to PAs (p = 0.048 and p = 0.053, respectively). Bioinformatic analysis suggested that all investigated micro RNAs function as negative regulators of MTDH. The results of this study suggest that all three micro RNAs have a considerable negative impact on MTDH oncogene expression in malignant tumors, while the differences between levels of miR-26a, miR-191, PLAG1, and HIF2 in PA and WT represent possible differential diagnosis markers.

PD-L1 and PD-L2 Expression in Different Tumor Stages and Types of Malignant Salivary Gland Neoplasms: A Single-center Experience.

There is a limited amount of data on the role of programmed cell death ligand (PD-L) -1 and PD-L2 in salivary gland carcinomas. We aimed to evaluate the prognostic value of PD-L1 and PD-L2 expressions, which are closely related to immune mechanisms, with respect to salivary gland tumor types and stages. Data from patients with salivary gland masses surgically removed between 2006 and 2021, diagnosed with a malignant salivary gland neoplasm, were retrospectively analyzed. Immunoreactivity for PD-L1 and PD-L2 was performed on resection materials. The mean age of 90 patients was 52.1±18.8 and 46.7% were male. Overall, 55.6% of patients were diagnosed with adenoid cystic carcinoma (ACC), 23.3% with mucoepidermoid carcinoma (MEC), 16.7% with acinic cell carcinoma (AciCC), 3.3% with ductal carcinoma (DC), and 1 patient with pleomorphic adenoma ex carcinoma (PA-ex-CA). In all, 52% of ACC, 12% of AciCC, 24% of MEC, and 12% of DC cases were at stage IV. The tumor diameter, frequencies of lymphovascular invasion, metastasis, positive surgical margin, recurrence, and mortality rates of patients at stages III and IV were significantly larger than those at stages I and II ( P <0.05). The percentages of tumor cell score (TCS) and immune cell score (ICS) for PD-L1 were significantly higher among patients with MEC compared with those with other types of tumors ( P =0.0011). However, the percentages of combined score (CS) for PD-L1 and tumor cell score for PD-L2 were comparable among tumor types ( P >0.05). No significant difference was found in these scores for PD-L1 between tumor stages ( P >0.05), but for PD-L2, all patients at stage I had TCS <1% for PD-L2, while all patients at stages II and III, and 92% of patients at stage IV had TCS ≥1% ( P <0.0001). High expression of PD-L1 was mostly observed in MEC cases ( P =0.0016), while all patients with AciCC had a low PD-L1 expression level ( P =0.0206). The mean tumor diameter, rate of lymphovascular invasion, perineural invasion, metastasis, positive surgical margin, recurrence, type of treatment, mortality, and TILs ratio did not differ significantly according to PD-L1 expression level ( P >0.05). The percentage of tumor-infiltrating lymphocytes was comparable among negative and positive PD-L1 scores according to both 1% and 5% threshold values ( P >0.05). High PD-L1 expression is rare in AciCC, while PD-L1 expression is high in MEC. Our findings underline the importance of future screening for PD-L1 and PD-L2 before patients undergoing immunotherapies in all salivary gland tumors.

Differential Expression of Mucin in Salivary Gland Tumours.

Background and Objectives: Mucin has been implicated via various mechanisms in the development and growth of tumour cells. However, mucin expression studies in salivary gland tumours are limited, especially with samples from minor salivary glands. This study aims to investigate and compare mucin expression in benign and malignant salivary gland tumours of minor and major salivary gland origins. Materials and Methods: Special stains were used to stain neutral mucin (Periodic acid Schiff), sialomucin (Alcian Blue) and sulfomucin (Aldehyde Fuschin) within tissues from six normal salivary glands and 73 salivary gland tumours including 31 pleomorphic adenomas, 27 mucoepidermoid carcinomas, and 15 adenoid cystic carcinomas. A semi-quantitative approach was used to evaluate mucin expression within ductal lumens. Sialomucin was the most expressed mucin in all salivary gland tumours, regardless of origin. Results: A significant difference was observed in the mucin expression between benign and malignant salivary gland tumours, as pleomorphic adenoma showed three times significantly higher expression of sialomucin compared to mucoepidermoid carcinoma and adenoid cystic carcinoma (p = 0.028). Pleomorphic adenomas of major glands showed 42 times significantly higher expression of sialomucin compared to those of minor glands (p = 0.000). Conclusions: Sialomucin content in pleomorphic adenomas of major glands was vastly increased compared to that in minor glands. Differential sialomucin expression in benign and malignant salivary gland tumours suggests a role in diagnosing of borderline salivary gland tumours.

Secretory carcinoma of minor salivary glands.

Secretory carcinoma is a malignant salivary gland tumor, which typically presents as an indolent painless mass within the parotid gland. Involvement of the minor gland is reported but less common. Secretory carcinoma was often misclassified as other salivary gland mimics, particularly acinic cell carcinoma, prior to 2010. It was first recognized as a molecularly distinct salivary gland tumor harboring the same fusion gene as well as histologic and cytogenetic features seen in juvenile breast cancer. Secretory carcinoma is generally managed in the same way as other low-grade salivary gland neoplasms and has a favorable prognosis; however, high-grade transformation requiring aggressive therapeutic interventions have been documented. Recent studies of biologic agents targeting products of this fusion gene offer the promise of a novel therapeutic option for treatment of this malignancy. Due to the limited number of reported cases, the spectrum of clinical behavior, best practices for management, and long-term treatment outcomes for secretory carcinoma remain unclear. A long-standing secretory carcinoma involving minor salivary glands of the mucobuccal fold, which was detected years after it was first noted by the patient, is reported. This case brings to light the importance of a thorough clinical exam during dental visits and reviews diagnostic differentiation of this malignancy from other mimics and discusses decision making for its management.

A Case of Parotid Carcinoma Ex Pleomorphic Adenoma with Mixture of Malignant Subtypes

Carcinoma ex pleomorphic adenoma is an uncommon malignant salivary gland tumor that arises from a longstanding pleomorphic adenoma. The carcinomatous component of carcinoma ex pleomorphic adenoma can possess virtually any histologic subtype of salivary gland cancer. We experienced a case of a 61-year-old patient who presented with a right parotid mass that was initially palpated 20 years ago, with a sudden increase in size in the last few months. Radiological and cytological findings from fine needle aspiration biopsy could not exclude malignancy. Total parotidectomy and selective neck dissection were performed for treatment, and carcinoma ex pleomorphic adenoma with mixed carcinoma components of salivary duct carcinoma and myoepithelial carcinoma was diagnosed. After receiving postoperative radiation of 6000 cGy over 6 weeks, there has been no recurrence up to the 18-month follow-up. We report this rare case of carcinoma ex pleomorphic adenoma with mixed malignancy subtypes, accompanied by a review of literature.

Frequent Immunohistochemical Expression of Transcriptional Repressor GATA Binding 1 in Salivary Gland Neoplasms: A Sensitive but Nonspecific Marker.

Salivary gland (SG) neoplasms (SGNs) display considerable immunophenotypic diversity. A significant proportion of SG carcinomas develop metastases with increased diagnostic difficulty at metastatic sites. Transcriptional repressor GATA binding 1 (TRPS1), a novel immunohistochemical marker for breast cancer, has been found to stain certain SGNs. To investigate TRPS1 and SRY-related HMG-box 10 (SOX10) immunoexpression in various SGNs and non-SG carcinomas, head and neck paragangliomas, and head and neck mucosal melanomas. TRPS1 immunoreactivity score (IRS) was determined as negative or low, intermediate, or high positive; SOX10 was reported as negative or positive. One hundred forty-eight SGNs, 5 breast carcinomas, 105 nonbreast-non-SG carcinomas, including 33 head and neck squamous cell carcinomas (HNSCCs), 6 head and neck paragangliomas, and 6 head and neck mucosal melanomas, were assessed for TRPS1. All 23 benign SGNs showed TRPS1 positivity, with the majority having high-positive IRS (17 of 23 cases; 74%). Among 125 SG carcinomas, 115 of 125 (92%) were TRPS1 positive, with high-positive IRS in 94 of 125 (75%), intermediate positive in 15 of 125 (12%), and low positive in 6 of 125 (5%). Among nonbreast-non-SG carcinomas, HNSCC, lung, thyroid, kidney, and ovarian carcinomas showed frequent TRPS1 staining. Nearly half of HNSCCs had high (11 of 18; 33%) or intermediate (4 of 18; 12%) positive IRS. Mean IRS in SG carcinomas was significantly higher than that in nonbreast-non-SG carcinomas (P < .001). None of the TRPS1-positive nonbreast-non-SG carcinomas expressed SOX10. TRPS1 is positive in most benign and malignant SGNs. Its expression in several nonbreast-non-SG carcinomas indicates that it lacks specificity for breast and SG carcinomas, even if considering only high-positive IRS. Addition of SOX10 can increase discriminatory utility of TRPS1.

First Case Report of Bilateral Parotid Lymphoepithelial Carcinoma.

The parotid is the largest salivary gland and is located anteriorly to the sternocleidomastoid muscle and laterally to the ramus of the mandible. Neoplasms in this gland are relatively rare, with 80% being benign and 20% malignant, primarily represented by mucoepidermoid carcinoma. In the head and neck region, lymphoepithelial carcinoma (LEC) accounts for 0.4% of malignant salivary gland tumors. A 35-year-old man with no previous comorbidities was admitted to a Head and Neck Surgery Specialty Service for a painless right cervical mass of uncertain growth. Extensive diagnostic investigation revealed involvement of the contralateral parotid, associated with systemic lymph node enlargement. Thus, adjuvant radiotherapy was decided by the treating team. This case confirms the heterogeneous features and distinctive behavior that the disease can present, as seen with bilateral parotid LEC.

MRI-based radiomics for predicting histology in malignant salivary gland tumors: methodology and "proof of principle".

Defining the exact histological features of salivary gland malignancies before treatment remains an unsolved problem that compromises the ability to tailor further therapeutic steps individually. Radiomics, a new methodology to extract quantitative information from medical images, could contribute to characterizing the individual cancer phenotype already before treatment in a fast and non-invasive way. Consequently, the standardization and implementation of radiomic analysis in the clinical routine work to predict histology of salivary gland cancer (SGC) could also provide improvements in clinical decision-making. In this study, we aimed to investigate the potential of radiomic features as imaging biomarker to distinguish between high grade and low-grade salivary gland malignancies. We have also investigated the effect of image and feature level harmonization on the performance of radiomic models. For this study, our dual center cohort consisted of 126 patients, with histologically proven SGC, who underwent curative-intent treatment in two tertiary oncology centers. We extracted and analyzed the radiomics features of 120 pre-therapeutic MRI images with gadolinium (T1 sequences), and correlated those with the definitive post-operative histology. In our study the best radiomic model achieved average AUC of 0.66 and balanced accuracy of 0.63. According to the results, there is significant difference between the performance of models based on MRI intensity normalized images + harmonized features and other models (p value < 0.05) which indicates that in case of dealing with heterogeneous dataset, applying the harmonization methods is beneficial. Among radiomic features minimum intensity from first order, and gray level-variance from texture category were frequently selected during multivariate analysis which indicate the potential of these features as being used as imaging biomarker. The present bicentric study presents for the first time the feasibility of implementing MR-based, handcrafted radiomics, based on T1 contrast-enhanced sequences and the ComBat harmonization method in an effort to predict the formal grading of salivary gland carcinoma with satisfactory performance.

Oncocytic Lesions of Salivary Glands: Morphological, Immunohistochemical, and Molecular Findings.

The fifth edition of the World Health Organization (WHO) classification introduces new diagnostic methods based on genetic alterations, providing insight into the molecular basis of lesions. As a result, the classification system has evolved, new entities have been introduced, and existing entities have been reclassified. Oncocytic lesions of salivary glands are a group of neoplastic conditions characterized bythe presence ofoncocytic cells. These lesions present a diagnostic challenge due to their overlapping histological features. Therefore, a comprehensive evaluation, including morphological, immunohistochemical, and molecular analysis, is crucial for accurate diagnosis and appropriate management. Accurate classification of salivary gland pathologies is essential for selecting the appropriate treatment methods and predicting outcomes. The introduction of new therapeutic approaches, such as targeted therapies for malignant salivary gland tumors, has improved patient outcomes. However, to effectively implement these therapies in clinical practice, a clear classification of lesions is necessary.

Molecular Aspects of Mucoepidermoid Carcinoma and Adenoid Cystic Carcinoma of the Salivary Gland.

Salivary gland tumors (SGTs) are rare and highly heterogeneous lesions, making diagnosis a challenging activity. In addition, the small number of studies and samples evaluated difficults the determination of prognosis and diagnosis. Despite the solid advances achieved by research, there is still an intense need to investigate biomarkers for diagnosis, prognosis and that explain the evolution and progression of SGTs. We performed a comprehensive literature review of the molecular alterations focusing on the most frequent malignant SGTs: mucoepidermoid carcinoma and adenoid cystic carcinoma. Due to the importance of biomarkers in the tumorigenenic process, this review aimed to address the mechanisms involved and to describe molecular and biomarker pathways to better understand some aspects of the pathophysiology of salivary gland tumorigenesis. Molecular analysis is essential not only to improve the diagnosis and prognosis of the tumors but also to identify novel driver pathways in the precision medicine scenario.