Basal cell adenocarcinoma of the soft palate: A closer look for an exceedingly rare salivary gland tumor

Basal cell adenocarcinoma (BCAd) is an extremely rare primary biphasic carcinoma of the salivary glands with few well-documented cases reported in the literature. Herein, we report a rare case of a 44-year-old male patient who presented an oral medicine service with an erythematous nodular lesion on the soft palate, measuring 1.5 cm in its largest diameter, with a 5-year duration. The clinical diagnosis was pleomorphic adenoma, and an excisional biopsy was performed. Histopathological analysis revealed a biphasic infiltrative tumor composed of a mixture of central ductal cells and abluminal basal cells with slight atypia arranged in solid, trabecular, tubular and cribriform growth patterns in a loose stroma. The peripheral cells show a palisading arrangement with round hyperchromatic nuclei and scanty cytoplasm. Occasional mitotic figures were seen. Few spindle-shaped cells suggestive of myoepithelial cells were present in the stroma surrounding the basaloid tumor nests. The diagnosis was BCAd. The patient was referred to a head and neck service and has been followed up for 8 months with no signs of recurrence. In conclusion, although the diagnosis of BCAd can be challenging due to its rarity and morphological overlap with other salivary gland lesions, a meticulous morphological assessment is key for accurate diagnosis, especially in cases originating from minor salivary glands. Surgical excision with a wide safety margin is the treatment of choice and long-term follow-up is recommended to monitor possible recurrences.

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.

TRPS1 immunohistochemical expression in salivary gland tumors: A pilot study

OBJECTIVES

TRPS1 is a new, sensitive marker for breast carcinoma (BC). Salivary glands and breasts are both exocrine glands; thus, their tumors may share similar morphology and immunophenotype. Among salivary gland-type BC, TRPS1 is reported to be positive in secretory carcinomas (SCs) but negative in acinic cell carcinomas (AciCCs) and most adenoid cystic carcinomas (AdCCs). A subset of salivary duct carcinomas (SDCs) is positive for TRPS1. Herein, we investigate TRPS1 immunohistochemical expression in salivary gland tumors (SGTs).

METHODS

A retrospective search yielded 110 SGTs (97 primary and 13 metastatic). TRPS1 immunohistochemistry was scored as negative, low positive, intermediate positive, or strongly positive.

RESULTS

TRPS1 was expressed in 78% (14/18) of pleomorphic adenoma (PA) cases but negative/low positive in all Warthin tumors (6/6 [100%]). In basal cell adenoma (BCA), TRPS1 expression was intermediate to strong (13/14 [92%]) in the stromal cells, whereas ductal or basal cells showed low expression. TRPS1 expression varied in malignant SGTs, with intermediate to strong staining in 100% (15/15) of AdCCs, 100% (5/5) of basal cell adenocarcinoma, 100% (3/3) of intraductal carcinoma, 89% (8/9) of polymorphous adenocarcinoma, and 89% (7/8) of SDCs; negative/low positive expression was observed in 100% (3/3) of SCs, 89% (8/9) of AciCCs, and 50% (3/3) of mucoepidermoid carcinomas. In addition, strong and intermediate TRPS1 expression was observed in metastatic SGT to the lungs, lymph nodes, and soft tissue.

CONCLUSIONS

Overall, TRPS1 is strongly expressed in PA as well as malignant and metastatic SGT. In addition, TRPS1 is positive in stromal cells of BCA but negative or low positive in ductal and basal cells.

Salivary Duct Carcinoma Arising in a Warthin Tumor of the Parotid Gland: A Rare Case Report with Review of Literature and PD-L1 Expression

Warthin's tumor is the second most common neoplasm of the parotid gland and consists of 2 components, including lymphoid stroma and glandular epithelium. Malignant transformation in this tumor is mostly seen in the lymphoid component; however, the carcinomatous transformation of the epithelial component is extremely rare. Cases of latter reported in the literature include squamous cell carcinoma, adenocarcinoma, mucoepidermoid carcinoma, oncocytic carcinoma, Merkel cell carcinoma, and undifferentiated carcinoma. We describe an extremely rare case of salivary duct carcinoma arising in a Warthin tumor in a 64-year-old male. Patient presented with an enlarging left parotid mass, biopsy of which showed salivary duct carcinoma. He subsequently underwent left parotidectomy along with left level II-IV lymph node dissection. Histology revealed both in situ as well as invasive salivary duct carcinoma arising from Warthin tumor. Immunohistochemistry showed tumor cells positive for CK7, AR, and GATA3, while p63 highlighted the myoepithelial cell layer in the in situ component. Her2 was 2+ by immunohistochemistry. In addition, PD-L1 IHC revealed positive expression with a combined positive score of 20%.

Clinicopathological characteristics of four major histological types of high-grade parotid carcinoma

OBJECTIVE

High-grade parotid carcinoma generally has a poor prognosis, and the histological type is mucoepidermoid carcinoma (MEC), salivary duct carcinoma (SDC), carcinoma ex pleomorphic adenoma (CEPA), or adenoid cystic carcinoma (AdCC) in the majority of cases.

METHODS

During the 23-year period from September 1999 to December 2022, 250 patients with parotid carcinoma underwent initial treatment and had the histopathological type of their carcinoma. Retrospective study evaluated 111 MEC, SDC, CEPA, or AdCC cases among 134 patients with high-grade parotid carcinoma. We examined pathological and clinical features and prognosis, evaluated factors associated with recurrence, and performed immunohistological examinations.

RESULTS

Pathological and clinical features and factors associated with recurrence were different for each histological type. The 10-year disease-free survival rates were as follows: MEC, 34.9%; SDC, 22.6%; CEPA, 47.1%; and AdCC, 56.3%. Human epidermal growth factor receptor type-2 and androgen receptor were positive in 48% and 56% of patients with SDC, respectively, 38% and 25% of those with CEPA.

CONCLUSION

Each histological type has its own pathological and clinical features, recurrence types, and tumor activities, suggesting that differentiating between high-grade parotid carcinomas according to histological type will improve diagnosis, and thus prognosis.

Clinicopathological characteristics of pleomorphic adenoma from the labial gland: A 20-year experience with 173 cases in one single institution

OBJECTIVE

Pleomorphic adenoma (PA) of the lip is not a common phenomenon, and existing literature provides limited information on the clinicopathological features of labial PA.

STUDY DESIGN

Patients diagnosed with labial PA at our single institution over the past 20 years (2001-2020) was retrospectively screened and analyzed to investigate the epidemiologic and clinicopathological features of these tumors.

RESULTS

A total of 173 cases were screened out, and the average age was 44.3 (range 7-82) years, with a peak incidence rate during the third decade. A slight predilection for men (52%) was observed, and PA occurs more frequently in the upper lip than in the lower lip, with a ratio of 14.7:1. On clinical examination, labial PAs usually present as painless masses that develop slowly with no systemic symptoms. Histologically, labial PAs contain myoepithelial and polygonal epithelial cells in myxoid, hyaline, fibrous, chondroid, and even osseous tissues, similar to those in other sites. Specifically, 15 of 173 patients with labial PA presented with cutaneous PA.

CONCLUSION

Labial PA presents over a wide age range and dominantly occurs at the upper lip. Surgical resection is the major treatment strategy, and postoperative recurrence or malignant transformation of labial PA was extremely rare.

Treatment and outcomes of minor salivary gland cancers of the larynx and trachea: a systematic review

Objectives

Malignant minor salivary glands carcinomas (MiSGC) of the larynx and trachea are rare tumours and published evidence is sparse. We conducted a systematic review to describe shareable treatment strategies and oncological outcomes of these neoplastic entities.

Methods

Full text English manuscripts published from January 1st 2000 to December 14th 2022 were included. Data on demographics, treatments and outcomes were collected. A pooled analysis of 5-year overall survival (OS) was performed.

Results

Seventeen articles and 365 patients met the inclusion criteria. The most common subsites involved were subglottic and distal trachea. Adenoid cystic carcinoma was, by far, the most frequent histotype. The first-choice treatment strategy was surgery (86.8%), while adjuvant treatments were delivered in 57.4% of patients. Only 12.9% were treated with definitive radiotherapy with/without chemotherapy. The mean follow-up was 68.3 months. One hundred nine (34.9%) deaths were recorded and 62.4% were cancer-related. Five-year OS ranged from 20% to 100% and, at pooled analysis, it was 83% (range, 78-87%).

Conclusions

In case of MiSGC of the larynx and trachea, surgery remains the mainstay of treatment. Adjuvant treatments are frequently delivered. Survival estimates are good overall, but highly heterogeneous.

Oncocytic Carcinoma in the Retromolar Trigone: A Case Report

Oncocytic carcinoma (OC) is a pretty rare malignant neoplasm. Oncocytic carcinomas mainly occur in major salivary glands but infrequently occur in minor salivary glands. We report a case of OC occurring in the retromolar glands involving the ipsilateral tonsil, which has not been reported in the English literature. This case may expand the database of OC, and provide diagnosis and treatment ideas for clinicians.

Challenging Tumor Heterogeneity with HER2, p16 and Somatostatin Receptor 2 Expression in a Case of EBV-Associated Lymphoepithelial Carcinoma of the Salivary Gland

BACKGROUND

Lymphoepithelial carcinoma of the salivary glands (LECSG) is a rare disease in the Western hemisphere that is typically associated with an EBV infection. The molecular mechanisms of LECSG tumorigenesis are poorly understood.

RESULTS

Here we report a case of EBV-associated LECSG with an unusual immunophenotype. The tumor exhibited bi-morphic histological features with a mutually exclusive expression of HER2 and p16. The p16-positive domain of the tumor immunohistochemically co-expressed late membrane protein 1 (LMP-1), while the HER2 positive domain did not. Both tumor regions expressed SSTR2.

METHODS

In situ hybridization confirmed the EBV origin of the tumor while extensive immunohistochemical characterization and the recently established RNA-based next generation sequencing panel ("SalvGlandDx" panel) did not reveal evidence for another salivary gland neoplasm. No HPV co-infection was detected by in situ hybridization or PCR-based screenings and no ERBB2 gene amplification was detected by fluorescence in situ hybridization.

CONCLUSION

These findings suggest tumor heterogeneity and lack of genomic aberrations in EBV-associated LECSGs. The heterogenous and unusual immunohistochemical features explain the diagnostic difficulties and simultaneously extend the immunophenotype spectrum of this tumor entity.

Milan system for reporting salivary gland cytology in diagnosis and surgery of parotid gland lesions

INTRODUCTION

A cytology report is always a challenge for both head and neck surgeons and cytopathologists to diagnose and manage parotid gland (PG) diseases, because of the various similar features between the lesions.

OBJECTIVES

The present study was conducted to assess our practice using the Milan System for Reporting Salivary Cytopathology (MSRSGC) and to evaluate the risk of malignancy (ROM) in different categories.

PATIENTS AND METHODS

The patients with parotid gland lesions were diagnosed by clinical examination, ultrasound, and FNAC under ultrasound guidance at our hospital from 1 May 2019 to 30 April 2021. The FNAC results were divided into six categories according to the Milan system. We calculated the ROM for each category of the Milan system based on histopathological follow-up.

RESULTS

This study included 204 patients. There were 115 men (56 %) aged 46-60 years. Pathology results were 33 cases for malignant and 182 cases for benign. The rate of malignancy for each category according to the MSRSGC were 23.1 % (non-neoplastic), 20 % (atypical), 50 % (neoplastic), 1 % (benign), 10.3 % (salivary neoplasm of uncertain neoplastic potential), 84.6 % (suspicious for malignancy), and 100 % (malignant) categories. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of FNAC with application of Milan system were respectively 90.9 %, 98.2 %, 90.9 %, 98.9 % and 97 %.

CONCLUSION

When the Milan system was applied, FNAC had a high efficacy, suggesting that MSRSGC can improve the communication between the cytopathologist and the surgeon. This system can allow the surgeon to decide the extent of the surgery.

P16 expression and presence of lymphoid stroma are correlated with good prognosis in mucoepidermoid carcinoma of the head and neck

BACKGROUND

Mucoepidermoid carcinoma (MEC) is the most common salivary gland malignancy. This study was designed to identify valuable prognosticator in MEC.

METHODS

Histopathologic analysis, immunohistochemistry, and in situ hybridization were performed on 128 carcinomas diagnosed as MEC of the head and neck.

RESULTS

Expression of p16 was found in 96 cases (76%) of MEC. Lymphoid stroma was identified in 63 cases (49%). There was a significant correlation between loss of p16 expression and absence of lymphoid stroma. Expression of p16 was significantly associated with better clinicopathologic features. Lymphoid stroma was significantly associated with lower histologic grade. Overall survival (OS) was significantly longer in cases expressing p16 (P = 0.00096) and lymphoid stroma cases (P = 0.0023). Multivariate analysis revealed loss of p16 expression as negative prognosticators for OS.

CONCLUSION

Our data showed p16 expression and the presence of lymphoid stroma were significantly associated with good clinical outcomes. Testing for these factors could lead to better prognostication and treatment of patients with MEC.

Salivary gland pathologies: evolution in classification and association with unique genetic alterations

PURPOSE

The correct classification of salivary gland pathologies is crucial for choosing a treatment method and determining the prognosis. Better outcomes are now achievable thanks to the introduction of new therapy approaches, such as targeted therapies for malignant salivary gland tumors. To apply these in clinical routine, a clear classification of the lesions is required.

METHODS

The following review examines all changes from the first World Health Organization (WHO) Classification of salivary gland pathologies from 1972 to fifth edition from 2022. Possible developments in the diagnosis and classification of salivary gland pathology are also presented.

RESULTS

The current WHO classification is the fifth edition. With the development of new diagnostic methods, based on genetic alterations, it provides insight into the molecular basis of lesions. This has resulted in the evolution of classification, introduction of new entities and reclassification of existing ones.

CONCLUSIONS

Genetic alterations will become increasingly more significant in the identification of salivary gland pathologies in the future. These alterations will be helpful as prognostic and predictive biomarkers, and may also serve as targets for anti-cancer therapies.

Cytopathology of salivary gland myoepithelial carcinoma: A study of 13 cases and review of the literature

INTRODUCTION

Myoepithelial carcinoma (MECA) is an infrequently recognized salivary gland (SG) neoplasm that commonly develops within a preexisting pleomorphic adenoma (MECA ex PA). Fine-needle aspiration (FNA) biopsy reports of this neoplasm are largely restricted to small series and single case reports.

METHODS

Our cytopathology files were searched for examples of SG MECA/MECA ex PA having confirmatory histopathologic verification. Conventional FNA biopsy smears were performed, and exfoliative specimens processed using standard techniques.

RESULTS

Thirteen cases from 9 patients (M:F = 3.5:1; age range: 36 to 95 years, mean age = 60 years) met inclusion criteria. FNA biopsy sites included parotid gland (4), trunk (2), scalp (2), and neck (2). Exfoliative specimens included pleural fluid (1), bronchial brushing (1), and bronchoalveolar lavage (1). Most cases were metastatic deposits (8; 62%), 4 were primary neoplasms, and 1 a local recurrence. FNA diagnoses were MECA ex PA (6; 46%), myoepithelial neoplasm (2), PA (2), basaloid neoplasm (1), atypical myoepithelial cells (1), and myxoma (1). Ancillary testing in 2 cases showed positive staining for myoepithelial markers. Cytologic features were that of a low-grade neoplasm composed principally of epithelioid/polygonal cells exhibiting minimal if any cytologic atypia. Myxoid and chondromyxoid stroma was often the dominant feature in MECA ex PA aspirates.

CONCLUSION

In the primary setting, a cytologic diagnosis of MECA/MECA ex PA is extremely challenging if at all possible. Due to overwhelming amounts of stroma, the diagnosis may be challenging in some cases of metastatic MECA ex PA.

Prognostic factors and treatment considerations of submandibular gland carcinomas: A population-based study

OBJECTIVES

The therapeutic regimen of submandibular gland carcinoma (SGC) has not reached consensus, especially for the neck treatment of patients with cN0.

MATERIALS AND METHODS

Patients with SGC were identified from the medical database of Shanghai Ninth People's Hospital. Kaplan-Meier analysis, univariate and multivariate Cox regression were employed to evaluate the survival and independent prognostic factors.

RESULTS

Two hundred and fifteen patients with SGC were retrospectively reviewed. The 5-year disease-free survival (DFS) and overall survival (OS) rates were 71.5% and 77.8%, respectively. Multivariate analysis revealed that histological grade, cT classification, cN classification, and perineural invasion (PNI) were independent prognostic factors for DFS, while histological grade, cT classification, cN classification, and age were those for OS. The neck dissection showed no significant survival benefit for patients with cN0. Lung was the most common site of distant metastasis (16.7%).

CONCLUSIONS

Histological grade, cT classification, cN classification, age, and PNI were independent prognostic factors of patient with SGC, which should be the main considerations for making therapeutic regimens. Our study also verifies the neck dissection of patient with cN0 is unnecessary, and postoperative radiotherapy (PORT) is vital for patients with pN+.

Mucoepidermoid carcinoma showing continuity with the surface mucosa of the oral cavity: a report of 14 cases

OBJECTIVE

We aimed to characterize the histology and the clinicodemographic features of mucoepidermoid carcinoma (MEC), showing continuity with the oral surface mucosa.

STUDY DESIGN

We reviewed 138 cases of intraoral MEC to identify cases that showed continuity with the surface mucosa and compared their clinicodemographic findings with those of MECs not showing continuity. We compared the sex ratio using the 2-sample Z-test and compared the age distribution using the 2-sample Kolmogorov-Smirnov test.

RESULTS

Of the 138 cases examined, 14 showed continuity with the surface mucosa. Their histology showed surface mucosa with an apparent transition to an infiltrating tumor with mucous, intermediate, and epidermoid tumor cells growing in solid and cystic patterns. Their clinical appearance ranged from firm submucosal nodules to erythematous to ulcerated lesions. They showed a strong female predilection (6:1) and sharply bimodal age distribution, with sharp peaks in the fourth and seventh decades.

CONCLUSIONS

Mucoepidermoid carcinomas that show continuity have a demographic pattern distinct from that of conventional MECs, showing a striking female predilection and bimodal age distribution and suggesting a difference in etiology. Pathologists should remain aware that MEC in the oral cavity can have a histologic appearance of surface origin to reach the correct diagnosis.

Prognostic factors for sublingual gland carcinoma: a population-based Surveillance, Epidemiology and End Results database study

OBJECTIVE

To identify the clinical features and prognostic factors for sublingual gland carcinoma.

METHODS

This was a case-control study. Patients with surgically treated sublingual gland carcinoma were retrospectively included in the Surveillance, Epidemiology and End Results database and divided into adenoid cystic carcinoma (ACC) and non-ACC groups. Primary outcome variables were disease-specific survival (DSS) and overall survival (OS). Prognostic factors for each group were analyzed using Cox models.

RESULTS

We included 251 patients (115 men and 136 women). Compared with the non-ACC group, the ACC group had a larger average tumor size and received more adjuvant radiotherapy. In patients with ACC, the pathologic grade had an independent impact on DSS and OS, and patients who were undergoing adjuvant chemotherapy had worse DSS than those who were not receiving chemotherapy. In the non-ACC group, pathologic grade IV, lymph node metastasis, and adjuvant chemotherapy were associated with poor DSS and OS, and tumor extension predicted worsening DSS.

CONCLUSIONS

In sublingual gland carcinoma, the pathologic grade and adjuvant chemotherapy were the most important prognostic factors, whereas lymph node metastasis had a negative impact in non-ACC patients but not in ACC patients.

[Myoepithelial tumors of soft tissue: A case of mixed tumor]

Myoepithelial neoplasms of soft tissue represent a rare entity which has been described only recently when compared to salivary gland tumors with whom they share histopathological and molecular features. The most common locations are the superficial soft tissues of the limbs and limb girdles. However, they can rarely occur in the mediastinum, abdomen, bone, skin and visceral organs. Benign forms (myoepithelioma and mixed tumor) are more frequent than myoepithelial carcinoma and the latter mostly affects children and young adults. Diagnosis is mainly based on histology, which shows a proliferation of myoepithelial cells of variable morphology with or without glandular structures in a myxoid background, and immunohistochemistry, which shows co-expression of epithelial and myoepithelial markers. Molecular tests are not mandatory, but in selected cases FISH analysis can prove useful as about 50% of myoepitheliomas show EWSR1 (or rarely FUS) rearrangements and mixed tumors show PLAG1 rearrangements. Here, we present a case of a mixed tumor of the soft tissue occuring in the hand with expression of PLAG1 in immunohistochemistry.

Cytological diagnosis of cribriform adenocarcinoma at a rare site

Cribriform adenocarcinoma of the salivary gland is a rare infiltrative tumour with a dearth of literature explaining the cytomorphology. There is no case reported in the tonsil on fine needle aspiration cytology. It can be differentiated from other salivary gland malignancies on the basis of pattern recognition and molecular analysis of cell blocks.

Malignant pleural effusion and pericardial effusion, an unusual presentation of metastatic adenoid cystic carcinoma of the floor of mouth: A case report with cyto-histopathological correlation

Adenoid cystic carcinoma (ACC) is an uncommon tumour that represents 5%-10% of salivary gland tumours and 1% of all head and neck malignancies. It is characterised by a protracted clinical course with late metastasis and poor long-term prognosis. We report the case of a 38-year-old woman presenting with pulmonary and pleural metastases, on the background of ACC of the floor of mouth, which had been treated 4 years ago with surgical excision and radiotherapy. Cytological evaluation of the pleural effusion showed exfoliated ACC tumour cells. Despite palliative chemotherapy, the patient developed disease progression including metastatic spread to the pericardium, and died of disease within a year. This case illustrates an unusual presentation of ACC and highlights the importance of considering this entity when encountering a basaloid neoplasm in extra-salivary locations.

Detection of salivary gland and sinonasal fusions by a next-generation sequencing based, ligation-dependent, multiplex RT-PCR assay

AIMS

The discovery of tumour type-specific gene fusion oncogenes in benign and malignant salivary gland and sinonasal (SGSN) tumours has significantly increased our knowledge about their molecular pathology and classification.

METHODS AND RESULTS

We developed a new targeted multiplexed next-generation sequencing (NGS)-based method that utilizes ligation dependent reverse-transcriptase polymerase chain reaction (LD-RT-PCR) to detect oncogenic fusion transcripts involving 116 genes, leading to 96 gene fusions known to be recurrently rearranged in these tumours. In all, 180 SGSN tumours (formalin-fixed, paraffin-embedded samples, 141 specimens and 39 core needle biopsies) from the REFCORpath (French network for rare head and neck cancers) with previously identified fusion genes by fluorescent in situ hybridisation (FISH), RT-PCR, or molecular immunohistochemistry were selected to test its specificity and sensitivity and validate its diagnostic use. Tested tumours encompassed 14 major tumours types, including secretory carcinoma, mucoepidermoid carcinoma, adenoid cystic carcinoma, salivary gland intraductal carcinoma, clear cell carcinoma, pleomorphic adenoma, adamantinoma-like Ewing Sarcoma, EWSR1::COLCA2 sinonasal sarcoma, DEK::AFF2 sinonasal carcinoma, and biphenotypic sinonasal sarcoma. In-frame fusion transcripts were detected in 97.8% of cases (176/180). Gene fusion assay results correlated with conventional techniques (immunohistochemistry [IHC], FISH, and RT-PCR) in 176/180 tumours (97.8%).

CONCLUSION

This targeted multiplexed NGS-based LD-RT-PCR method is a robust, highly sensitive method for the detection of recurrent gene fusions from routine clinical SGSN tumours. It can be easily customized to cover new fusions. These results are promising for implementing an integrated NGS system to rapidly detect genetic aberrations, facilitating accurate, genomics-based diagnoses, and accelerate time to precision therapies in SGSN tumours.

Adenoid cystic carcinoma in children and young adults: A clinicopathological study of 12 cases

OBJECTIVE

To investigate the clinicopathological characteristics, immunoprofile, and molecular alterations of adenoid cystic carcinoma (ACC) in children and young adults.

MATERIALS AND METHODS

Twelve cases of ACC were included. MYB, MYBL1, Ki-67, type IV Collagen, Laminin, and LAMB1 expression were detected by immunohistochemistry. MYB and MYBL1 rearrangements were detected by fluorescence in situ hybridization.

RESULTS

Among 12 patients, four were female and eight were male. Seven cases (58.3%) located in major salivary glands and eight cases (66.7%) were classified as Grade I. Ten tumors (83.3%) had collagenous and hyalinized stroma. MYB was positive in 83.3% cases, and the average Ki-67 labeling index (LI) was 8.3%. LAMB1, type IV Collagen, and Laminin were positive in 91.7%, 66.7%, and 58.3% cases, respectively. Besides, three out of eight tumors had MYB rearrangement. Cases without MYB rearrangement were negative for MYBL1 expression and MYBL1 rearrangement. The average follow-up time was 91.8 months. Four patients had recurrent diseases.

CONCLUSIONS

ACC in children and young adults was seen more frequently in males and major salivary glands. Most cases had ECM and hyaline stroma. Grade III tumors, higher Ki-67 LI, negative expression of type IV Collagen, and Laminin showed a tendency of higher recurrence rate.

Risk of Carcinoma in Pleomorphic Adenomas of the Parotid

Importance

Surgery is the mainstay of treatment for pleomorphic adenomas (PAs) of the parotid to prevent further growth and potential future malignant transformation. While historical case series have reported transformation rates as high as 10%, there is a lack of contemporary methodologically sound data.

Objective

To examine the rate of carcinoma ex pleomorphic adenoma (CXPA) detection in untreated PAs and investigate factors associated with malignant neoplasm.

Design, Setting, and Participants

This cohort study reviewed all cases of primary PAs managed at a quaternary referral center between December 1990 and January 2015. Patients whose clinical presentation was compatible with a primary benign PA and whose history indicated tumor duration of over 1 year were included. Data were analyzed from January to April 2023.

Exposure

Untreated PA.

Main Outcomes and Measures

Rate of CXPA detection among untreated PAs and association of tumor duration with rates of CXPA detection. Pathology slides of patients who underwent surgery were reviewed by a single expert pathologist for the presence of CXPA. Univariable logistic regression was performed to evaluate possible factors associated with CXPA.

Results

A total of 260 patients (median age, 47 years [IQR, 38-60 years]; 174 [66.9%] female) had a median tumor duration of 3.2 years (range, 1-30 years; mean [SD], 5.7 [5.5] years). Patients were divided into 4 groups by tumor duration: 1 to 4 years (158 [60.7%]), 5 to 9 years (47 [18.1%]), 10 to 14 years (27 [10.4%]), and 15 to 30 years (28 [10.8%]). In 156 of 170 patients who underwent preoperative fine-needle aspiration (91.8%), a benign tumor was diagnosed; 5 of these patients (3.2%; 95% CI, 1.4%-7.3%) were later diagnosed with CXPA on pathology after eventual excision, and the rate of high grade CXPA was 1.3%. None of the patients had permanent facial nerve paralysis. Tumor size at presentation (odds ratio [OR], 1.66; 95% CI, 1.22-2.24) and incremental (per year) increase in age (OR, 1.04; 95% CI, 1.01-1.08) were found to be associated with CXPA, whereas tumor duration was not (OR, 1.00; 95% CI, 1.00-1.01).

Conclusions and Relevance

In this study, the rate of malignant neoplasm detection among initially untreated PA was 3.2%. The results suggest that tumor size and older age are associated with the development of CXPA, while tumor duration is not. Observation of PA for longer periods was not associated with serious permanent complications.

Comprehensive Molecular Characterization of Polymorphous Adenocarcinoma, Cribriform Subtype: Identifying Novel Fusions and Fusion Partners

Polymorphous adenocarcinoma (PAC) is a common, usually low-grade salivary gland carcinoma. While conventional PACs are most associated with PRKD1 p.E710D hotspot mutations, the cribriform subtype is often associated with gene fusions in PRKD1, PRKD2, or PRKD3. These fusions have been primarily identified by fluorescence in situ hybridization (FISH) analysis, with a minority evaluated by next-generation sequencing (NGS). Many of the reported fusions were detected by break-apart FISH probes and therefore have unknown partners or were negative by FISH altogether. In this study, we aimed to further characterize the fusions associated with PAC with NGS. Fifty-four PACs (exclusively cribriform and mixed/intermediate types to enrich the study for fusion-positive cases) were identified and subjected to NGS. Fifty-one cases were successfully sequenced, 28 of which demonstrated gene fusions involving PRKD1, PRKD2, or PRKD3. There were 10 cases with the PRKD1 p.E710D mutation. We identified a diverse group of fusion partners, including 13 novel partners, 3 of which were recurrent. The most common partners for the PRKD genes were ARID1A and ARID1B. The wide variety of involved genes is unlike in other salivary gland malignancies and warrants a broader strategy of sequencing for molecular confirmation for particularly challenging cases, as our NGS study shows.

Induction of perineural invasion in salivary adenoid cystic carcinoma by circular RNA RNF111

OBJECTIVE

Local recurrence, distant metastasis, and perineural invasion (PNI) viciously occur in salivary adenoid cystic carcinoma (SACC), resulting in a poor prognosis. This study aimed to explore the mechanism by which circular RNA RNF111 (circ-RNF111) regulates PNI in SACC by targeting the miR-361-5p/high mobility group box 2 (HMGB2) axis.

METHOD

Circ-RNF111 and HMGB2 were highly expressed in SACC specimens, while miR-361-5p was underexpressed. Functional experiments showed that ablating circ-RNF111 or promoting miR-361-5p hindered the biological functions and PNI of SACC-LM cells.

RESULTS

HMGB2 overexpression induced the reversal of SACC-LM cell biological functions and PNI caused by circ-RNF111 knockout. Furthermore, reduction of circ-RNF111 suppressed PNI in a SACC xenograft model. Circ-RNF111 regulated HMGB2 expression through targeted modulation of miR-361-5p.

CONCLUSION

Taken together, circ-RNF111 stimulates PNI in SACC by miR-361-5p/HMGB2 axis and may serve as a potential therapeutic target for SACC.

Identifying potential immuno-oncology targets in salivary gland mucoepidermoid carcinoma based on inflammatory status and treatment response

BACKGROUND

Mucoepidermoid carcinoma is a rare salivary gland malignant tumour. This study aimed to investigate inflammatory and immune signatures of mucoepidermoid carcinoma by identifying potential proteo-transcriptomic biomarkers towards the development of precision immuno-oncology treatment strategies.

METHODS

A total of 30 biopsies obtained from patients diagnosed with mucoepidermoid carcinoma between 2013 and 2022 were analysed after H&E staining for scoring of histological inflammatory stroma subtypes and inflammatory hotspots with QuPath. Multiplex immunofluorescence staining and NanoString nCounter PanCancer IO 360™ panel were used to assess stroma and tumour inflammation signatures in high grade mucoepidermoid carcinoma cases in the tumour microenvironment via proteomics and transcriptomics, respectively.

RESULTS

Inflammatory cells within the histological inflammatory stroma inflammatory (HIS-INF/hot) tumour neighbourhoods were greater compared to the histological inflammatory stroma-immune desert (HIS-ID/cold) (p = 0.001). A similar trend was observed between treatment non-responders and responders in stroma neighbourhoods (p = 0.0625) and in stroma-to-interface inflammatory hotspots (p = 0.0081), indicating an augmented inflammatory response in hot tumours and non-responders. Furthermore, there were striking differences in the expression of pan-immune leukocyte marker CD45 between responders and non responders particularly in the tumour neighbourhoods (p = 0.0341), but such were not robust for PD-1 and macrophage fractions. Additionally, transcriptomic analysis revealed key differences in leukocyte activation profiles between responders and non-responders.

CONCLUSION

This preliminary report unveils the importance of assessing immune leukocyte cellular fractions and pathways for future prognostic biomarker discoveries in mucoepidermoid carcinoma as per the involvement of CD45-driven inflammatory and immune mediators in high grade mucoepidermoid carcinoma in non-responders to treatment. These findings will potentially contribute to the development of novel personalised immunotherapies.

A retrospective study of nonneoplastic and neoplastic disorders of the salivary glands

The spectrum of major and minor salivary gland disorders varies widely. Epidemiological data on some injury categories are rare and often not up-to-date. This study aims to analyze epidemiological data using clinical, paraclinical, and histopathological parameters. Study was carried out for 5 years on the nonneoplastic and tumoral pathology of the salivary glands. Data were statistically analyzed using the appropriate parameters. Data analysis according to the biological behavior of the lesions revealed great heterogeneity. Statistically significant correlations were observed between the type of injury, age (P = .002) and gender (0.033). The environment of origin of the patients as well as the comorbidities reflected in most cases the nature of the process. Associations were also observed between the biological behavior of the lesions and the hemicranial topography (P = .019), the type of salivary gland (P = .024), and the surgical technique used (P < .001). Most cases were identified in the major salivary glands, often in the parotid. The most common diseases are represented by nonspecific chronic sialadenitis (nonneoplastic lesion), pleomorphic adenoma and Warthin tumor (benign tumors), mucoepidermoid carcinoma (malignant tumor), and squamous carcinoma (secondary tumor). They presented axial diameters between 2 to 95 mm. The most used curative technique was subtotal excision with facial nerve preservation. In conclusion, the study highlighted the main epidemiological aspects of salivary gland disorders. Some data agree with the specialty literature, and particular aspects are also observed. Therefore, this research is useful both in the medical and research fields.

Intradural extramedullary metastasis of oncocytic carcinoma of the parotid gland: A first case report and review of the literature

We present an extremely infrequent case of intradural metastasis of a parotid tumour, responsible for motor deficit in legs. To our knowledge, this is the first reported case of an intradural metastasis of a malignant and rare parotid tumour, oncocytic carcinoma. It accounts for less than 1% of salivary gland tumours. Its management is not codified and its prognosis seems to be poor. Local recurrences are common, as are regional metastases. Distant metastases are present in less than 30% of cases and are poorly described, mainly involving the lung. Thanks to the surgical treatment, our patient has partially recovered his motor and sensory functions.

Selinexor for the treatment of recurrent or metastatic salivary gland tumors: Results from the GEMS-001 clinical trial

OBJECTIVES

We aimed to evaluate the activity of selinexor, an oral selective inhibitor of nuclear export, in patients with recurrent or metastatic salivary gland tumors (SGT).

METHODS

GEMS-001 is an open-label Phase 2 study for patients with recurrent or metastatic SGT with two parts. In Part 1 of the protocol, patients had tumor samples profiled with targeted next generation sequencing as well as immunohistochemistry for androgen receptor, HER-2 and ALK. For Part 2, patients with no targeted therapies available were eligible to receive selinexor 60 mg given twice weekly every 28 days. The primary endpoint was objective response rate. Secondary endpoints included progression-free survival (PFS) and prevalence of druggable alterations across SGT.

RESULTS

One hundred patients were enrolled in GEMS-001 and underwent genomic and immunohistochemistry profiling. A total of 21 patients who lacked available matched therapies were treated with selinexor. SGT subtypes (WHO classification) included adenoid cystic carcinoma (n = 10), salivary duct carcinoma (n = 3), acinic cell carcinoma (n = 2), myoepithelial carcinoma (n = 2), carcinoma ex pleomorphic adenoma (n = 2) and other (n = 2). Of 18 evaluable patients, stable disease (SD) was observed in 17 patients (94%) (SD ≥6 months in 7 patients (39%)). However, no objective responses were observed. The median PFS was 4.9 months (95% confidence interval, 3.4-10). The most common treatment-related Grade 1-2 adverse events were nausea [17 patients (81%)], fatigue [16 patients (76%)], and dysgeusia [12 patients (57%)]. Most common treatment-related Grade 3-4 adverse events were hyponatremia [3 patients (14%)], neutrophil count decrease [3 patients (14%)] and cataracts [2 patients (10%)]. No treatment-related deaths were observed.

CONCLUSIONS

Although tumor reduction was observed across participants, single agent selinexor anti-tumor activity was limited.

Infarction of basal cell adenoma of the parotid gland: First case report and literature review on CTNNB1 I35T mutations in salivary basal cell neoplasms

Infarction has rarely been reported in some types of salivary gland tumors. In this study, we present the first case of infarction occurring in salivary basal cell adenoma. A 62-year-old male presented with swelling in the left parotid region. Histopathological examination revealed extensive central necrosis surrounded by a rim of viable tumor tissue showing the typical histology of basal cell adenoma. Nuclear β-catenin expression and the CTNNB1 p.I35T (c.104 T > C) mutation were identified in the tumor. A diagnosis of basal cell adenoma with central necrosis was made, and the postoperative period was uneventful. In addition, we review the literature on CTNNB1 I35T mutations in basal cell neoplasms of the salivary glands. Awareness of the possible occurrence of infarction and the high frequency of the unique mutation in basal cell adenoma may help in the differential diagnosis of salivary gland tumors.

Clinical features of tumours and tumour-like pathologies involving the buccal fat pad

This study aimed to investigate the clinical, radiological, and pathological characteristics of pathologies involving the buccal fat pad (BFP) and to explore the treatment protocols. The cases of 109 patients with primary pathologies involving the BFP (pBFP) diagnosed between January 2013 and September 2021 were assessed. The patients' clinical presentations and radiological and histopathological findings were analysed retrospectively, and their treatment outcomes were evaluated. The 109 pBFP were categorized as benign tumours (n = 17), malignant tumours (n = 29), vascular malformations (n = 38), and inflammatory masses (n = 25). Of the 17 benign tumours, seven were lipomas, five were pleomorphic adenomas, three were solitary fibrous tumours, and two were other tumours. The 29 malignant tumours included five adenoid cystic carcinomas, six mucoepidermoid carcinomas, three synovial sarcomas, and 15 other tumours. Of the 38 vascular malformations, 37 were venous and one was arteriovenous. Regarding the inflammatory masses, the lesions appeared after cosmetic facial botulinum toxin injection in 13 cases and after other cosmetic facial procedures in five. The upper body of the BFP was the most frequently involved site (79/109), while other frequently involved sites were the lower body (67/109) and the masseteric (41/109), temporal (32/109), and pterygopalatine (30/109) extensions.

A novel STRN3::PRKD1 fusion in a cribriform adenocarcinoma of salivary gland with high-grade transformation

Cribriform adenocarcinoma of salivary gland (CASG) is a rare form of salivary gland neoplasm that mostly arises from minor salivary glands. We report a case of CASG with high-grade transformation harboring a novel STRN3::PRKD1 fusion. A 59-year-old male presented with a palatal mass. Morphologically, the tumor consisted of two components: solid high-grade and glandular low-grade areas. The solid high-grade area comprised solid nests of high-grade carcinoma with central necrosis arranged in lobules delineated with prominent stromal septa. The glandular low-grade area comprised of cribriform and microcystic architecture in a hyalinized and hypocellular stroma. Immunophenotypically, the tumor was positive for S100 but negative for p40 and actin. However, due to the high-grade component, tissue was sent for salivary gland NGS fusion panel analysis to confirm the diagnosis. The current case illustrates high-grade transformation in CASG. Furthermore, identification of a STRN3::PRKD1 fusion expands the genetic spectrum of CASG.

Genome Doubling Shapes High-Grade Transformation and Novel EWSR1::LARP4 Fusion Shows SOX10 Immunostaining in Hyalinizing Clear Cell Carcinoma of Salivary Gland

Hyalinizing clear cell carcinoma (HCCC) is a rare indolent malignant tumor of minor salivary gland origin with EWSR1::ATF1 rearrangement. Pathologically, the tumor cells possess a clear cytoplasm in a background of hyalinized stroma. Generally, the tumor cells are positive for p63 and p40 and negative for s100 and α-smooth muscle actin, suggesting that they differentiate into squamous epithelium and not into myoepithelium. In this study, we performed a detailed histopathological and genomic analysis of 6 cases of HCCC, including 2 atypical subtypes-a case of "high-grade transformation" and 1 "possessing a novel partner gene for EWSR1." We performed a sequential analysis of the primary and recurrent tumor by whole-exome sequencing, RNA sequencing, Sanger sequencing, and fluorescence in situ hybridization to investigate the effect of genomic changes on histopathology and clinical prognosis. A fusion gene involving the EWSR1 gene was detected in all cases. Five cases, including the "high-grade transformation," harbored a known EWSR1::ATF1 fusion gene; however, 1 case harbored a novel EWSR1::LARP4 fusion gene. This novel EWSR1::LARP4-fused HCCC has a SOX10-positive staining, which is different from the EWSR1::ATF1-fused HCCC. According to whole-exome sequencing and fluorescence in situ hybridization analysis, the "whole-genome doubling" and focal deletion involving CDKN2A, CDKN2B, and PTEN were detected in HCCC with "high-grade transformation." Conclusively, we identified a novel partner gene for EWSR1, LARP4, in indolent HCCC. Importantly, "high-grade transformation" and poor prognosis were caused by whole-genome doubling and subsequent genomic aberrations.

Pleomorphic Adenoma of the Palate: A Rare Case in an Adolescent With Cleft lip and Palate

Benign salivary gland tumors are rarely found in children and adolescents compared with adults. Pleomorphic adenomas (PAs), the most common benign salivary gland tumor, account for only 1% of all head and neck lesions and fewer than 5% of all salivary gland tumors in individuals under the age of 16 years. The data on palatal PA in the first 2 decades of life is confined to published case reports and case series. To date, there has never been a report of palatal PA in a patient with cleft lip and palate. Here we describe an adolescent female with bilateral cleft lip and palate with PA of the hard and soft palate who underwent wide local excision and reconstruction with a buccal fat pad and buccal myo-mucosal flap.

Primary Pulmonary Hyalinizing Clear Cell Carcinoma: Case Series With Review of Literature

Background: Hyalinizing clear cell carcinomas of tracheobronchial origin are very rare salivary gland type tumors accounting for less than 1% of lung tumors with only 13 cases reported to date. Their radiological features, morphological spectrum, and molecular features are not well described. Aim: To perform a clinicopathological analysis of primary pulmonary hyalinizing clear cell carcinomas. Method: A retrospective search of primary pulmonary hyalinizing clear cell carcinomas was conducted from authors' institutions and the clinicopathological features including details of molecular testing were analyzed. Results: Five primary pulmonary hyalinizing clear cell carcinomas were identified. The mean patient age at diagnosis was 48.2 years (range: 33-64 years). Three patients were women. All patients were nonsmokers and 3 were symptomatic; 2 were detected incidentally during health screening. The tumors were located in the main lobar bronchi ranging from 1.3 to 4.9 cm in maximum dimension. Microscopy showed cords and nests of at least, focally clear tumor cells. Mucin cysts lacking goblet cells were seen. All tumors were uniformly positive for p40, p63, AE1/AE3, keratin 7, and epithelial membrane antigen but negative for TTF1, KIT, neuroendocrine markers, and other myoepithelial markers. All cases showed Ewing sarcoma breakpoint region 1 (EWSR1) gene rearrangement. Perineural invasion and lymph node metastases were detected in patient 5. Two patients with available follow-up data were recurrence-free until 4 years (patient 1) and 9 months (patient 5) after resection. Conclusion: The present series adds to the scant available literature on primary pulmonary hyalinizing clear cell carcinomas highlighting the characteristic histomorphology, immunoprofiles, and benign outcomes of these rare tumors.

Prognostic scores for patients with salivary adenoid cystic carcinoma without lymph node metastasis

Adenoid cystic carcinoma (AdCC) of salivary gland grows relatively slowly, but occasionally develops distant metastasis. Although cervical lymph node metastasis (LNM) has been reported as a strong prognostic factor, most of AdCC do not have LNM. In this study, we investigated the prognostic factors to predict disease free survival (DFS), distant metastasis free survival (DMFS), and overall survival (OS) for 175 patients surgically treated for AdCC without LNM, and developed prognostic score (PS) determined as number of positive prognostic factors. The following emerged as significant prognostic factors: positive surgical margin in DFS, pT3/4 and positive surgical margin in DMFS, and positive surgical margin and high-histological grade in OS. 10-year DFS rates were 56.4% in PS0, and 19.1% in PS1 (p < 0.0001). 10-year DMFS rates were 86.3% in PS0, 56.4% in PS1, and 30.7% in PS2 (p < 0.0001). 10-year OS rates were 100% in PS0, 73.3% in PS1, and 38.8% in PS2 (p < 0.0001).

Palisading Adenocarcinoma: A Morphologically Unique Salivary Gland Tumor With a Neuroendocrine-like Appearance and a Predilection for the Sublingual Glands of Women

Adenocarcinoma, not otherwise specified (NOS) is a heterogenous group of salivary gland tumors that likely contains distinct tumors that have not yet been characterized. Indeed, in recent years, cases previously diagnosed as adenocarcinoma, NOS have been recategorized into novel tumor designations such as secretory carcinoma, microsecretory adenocarcinoma, and sclerosing microcystic adenocarcinoma. We sought to describe a distinctive, hitherto-undescribed salivary gland tumor encountered in the authors' practices. Cases were pulled from the surgical pathology archives of the authors' institutions. Histologic, immunohistochemical, and clinical findings were tabulated, and targeted next-generation sequencing was performed on all cases. Nine cases were identified, arising in 8 women and 1 man ranging from 45 to 74 years (mean, 56.7 y). Seven tumors (78%) arose in the sublingual gland, while 2 (22%) arose in the submandibular gland. The cases shared a distinctive morphologic appearance. They were biphasic, with ducts scattered among a predominant polygonal cell with round nuclei, prominent nucleoli, and pale eosinophilic cytoplasm. These cells were arranged as trabeculae and palisaded as pseudorosettes around hyalinized stroma and vessels, resembling a neuroendocrine tumor. Four of the cases were well-circumscribed, while the remaining 5 showed infiltrative growth including perineural invasion in 2 (22%) and lymphovascular invasion in 1 (11%). Mitotic rates were low (mean, 2.2/10 HPFs); necrosis was absent. By immunohistochemistry, the predominant cell type was strongly positive for CD56 (9 of 9) and variably positive for pan-cytokeratin (AE1/AE3) (7 of 9) with patchy S100 (4 of 9), but negative for synaptophysin (0 of 9) and chromogranin (0 of 9), while the ducts were strongly positive for pan-cytokeratin (AE1/AE3) (9 of 9) and CK5/6 (7 of 7). Next-generation sequencing did not reveal any fusions or obvious driver mutations. All cases were resected surgically, with external beam radiation also done in 1 case. Follow-up was available in 8 cases; there were no metastases or recurrences after 4 to 160 months (mean, 53.1 mo). A dual population of scattered ducts with a predominance of CD56-positive neuroendocrine-like cells characterizes a unique salivary gland tumor which is often encountered in the sublingual glands of women, for which we propose the term "palisading adenocarcinoma." Although the tumor was biphasic and had a neuroendocrine-like appearance, it lacked convincing immunohistochemical evidence of myoepithelial or neuroendocrine differentiation. Although a subset showed unequivocally invasive growth, this tumor appears to behave in an indolent manner. Moving forward, recognition of palisading adenocarcinoma and its separation from other salivary adenocarcinomas, NOS will facilitate a better understanding of the characteristics of this previously unrecognized tumor.

Clinical and Histopathologic Analyses of Nasopharyngeal Hyalinizing Clear Cell Carcinoma: A Series of 26 Cases With Molecular Confirmation

The aim of this study was to evaluate the clinicopathologic features, molecular characteristics, treatment strategy, and prognosis of nasopharyngeal hyalinizing clear cell carcinoma (HCCC). Retrospective observational case series. Institutional pathology records between 2006 and 2022 were searched for all cases of nasopharyngeal HCCC. We included 10 male and 16 female patients aged 30 to 82 years (median: 60.5 y, mean: 54.6 y). The most common symptoms were blood-stained rhinorrhea and nasal obstruction. Tumors most often involved the lateral wall of the nasopharynx, followed by the superior posterior wall. Microscopically, all tumor cells were arranged in sheets, nests, cords, and single cells in a hyaline/myxoid/fibrous stroma. The tumor cells were polygonal, with or without distinct cell borders, and displayed abundant clear-to-eosinophilic cytoplasm. All 26 cases were positive for pancytokeratin, CK7, p40, and p63 but negative for myoepithelial differentiation markers. Ki-67 labeling was low and ranged from 1% to 10%. All 26 cases demonstrated EWSR1 and EWSR1-ATF1 rearrangements, and no case demonstrated MAML2 rearrangement. Complete follow-up data were available for 23 patients: 14 patients underwent endoscopic surgery alone, 5 underwent radiation therapy followed by endoscopic surgery, 3 underwent radiation therapy followed by biopsy, and 1 underwent cisplatin chemotherapy before endoscopic surgery. Clinical follow-up ranged from 6 to 195 months; 13 patients (56.5%) were alive without tumor, 5 patients (21.7%) died of disease, 5 patients (21.7%) survived with tumor. HCCCs of the nasopharynx are rare tumors. The definitive diagnosis depends on histopathology, immunohistochemistry, and molecular studies. The optimal treatment for patients with nasopharyngeal HCCC is wide local excision. Radiation and chemotherapy might be good options for managing locally advanced cases. Nasopharyngeal HCCC is less indolent than previously thought. Tumor stage and the choice of treatment are key factors affecting the prognosis of nasopharyngeal HCCC patients.

Epithelial-myoepithelial carcinoma with multiple recurrences: An unusual presentation

Epithelial-myoepithelial carcinoma (EMC) is a type of malignant salivary gland tumors that is extremely rare. EMC primarily affects major salivary glands, particularly the parotid gland, but minorsalivary glands are also affected. It contributes less than 0.5-1% of all salivary gland neoplasms. Multiple recurrences are relatively rare with EMC. There have been very few reports of multiplerecurrences in the literature. Biphasic tubular structures composed of externalclear cells and inner ductal cells are the distinguishing histopathological feature. However, histological variation is prevalent, making a precise diagnosis challenging. We present a case of EMC that had multiple recurrences during a six-year period.

A Case of Metastatic Submandibular Salivary Duct Carcinoma that Completely Responded to Pembrolizumab Monotherapy

Salivary gland carcinoma is a rare cancer and has more than 20 histopathological types. Although chemotherapy has been the mainstay of treatment for unresectable carcinomas such as multiple recurrence and distant metastasis, no standard regimen is available. In this article, we report a case of poorly differentiated salivary duct carcinoma of the submandibular gland with distant metastases that was successfully treated with pembrolizumab monotherapy. A 66-year-old man became aware of a left submandibular mass 2 months before his first visit to our department. A needle biopsy at a previous hospital revealed carcinoma, not otherwise specified. The combined positive score on a programmed death ligand-1 immunohistochemistry test was 1-10%. The patient was referred to our department for further treatment. Computed tomography revealed left level II and IV neck lymphadenopathy, bilateral lung shadowing, and osteolytic changes in the 12th thoracic vertebra. Needle biopsy showed poorly differentiated carcinoma, positive human epidermal growth factor receptor 2, and positive androgen receptor, which suggested salivary duct carcinoma. These findings indicated a diagnosis of submandibular carcinoma T4aN2bM1 stage IVC. Pembrolizumab monotherapy was started, and tumor shrinkage was observed after three courses of treatment. At 1 year, complete response was achieved without adverse events, and treatment is ongoing. Despite a lack of evidence for the efficacy of immune checkpoint inhibitors in salivary gland carcinoma, the present case suggests that some patients might respond to this treatment. Hence, clinical trials are warranted.

A Review of the Molecular Landscape of Adenoid Cystic Carcinoma of the Lacrimal Gland

Adenoid cystic carcinoma (ACC) has a worldwide incidence of three to four cases per million population. Although more cases occur in the minor and major salivary glands, it is the most common lacrimal gland malignancy. ACC has a low-grade, indolent histological appearance, but is relentlessly progressive over time and has a strong proclivity to recur and/or metastasise. Current treatment options are limited to complete surgical excision and adjuvant radiotherapy. Intra-arterial systemic therapy is a recent innovation. Recurrent/metastatic disease is common due to perineural invasion, and it is largely untreatable as it is refractory to conventional chemotherapeutic agents. Given the rarity of this tumour, the molecular mechanisms that govern disease pathogenesis are poorly understood. There is an unmet, critical need to develop effective, personalised targeted therapies for the treatment of ACC in order to reduce morbidity and mortality associated with the disease. This review details the evidence relating to the molecular underpinnings of ACC of the lacrimal gland, including the MYB-NFIB chromosomal translocations, Notch-signalling pathway aberrations, DNA damage repair gene mutations and epigenetic modifications.

Secretory Carcinoma with ETV6-NTRK3 Gene Fusion and Lymph Node Metastasis in Maxillary Gingiva: A Case Report with Pathological and Molecular Correlative Studies

Secretory carcinoma (SC), also known as mammary analogue secretory carcinoma (MASC), is a rare salivary gland neoplasm with distinctive morphology that harbors a diagnostic ETV6 gene rearrangement. MASC was first described as a type of salivary gland neoplasm in 2010 and resembles breast secretory carcinoma. It is often mistaken for other neoplasms. It usually acts as an indolent tumor but can occasionally behave in an aggressive manner. We present a rare case of a patient with an aggressive SC/MASC of maxillary gingivobuccal sulcus with microcystic, solid and papillary patterns that showed ETV6 gene rearrangement by fluorescence in situ hybridization. Next-generation sequencing revealed t(12;15)(p13;q25) ETV6-NTRK3 translocation. Because SC/MASCs harbor the ETV6-NTRK3 translocation, molecular studies and immunostains are crucial to confirm the diagnosis and direct therapy.

Prognostic factors in surgically treated malignant salivary gland tumors

OBJECTIVES

To identify prognostic factors for evidence-based risk stratification in malignant salivary gland tumors.

METHODS

This retrospective study identified 162 patients who presented with malignant salivary gland tumors between 2010 and 2020. Final analysis included 91 patients who underwent surgical treatment at our institution and were followed-up for ≥ 1 year. Medical records were reviewed and patients were categorized according to their risk profile.

RESULTS

This study included 91 patients (51 males, 40 females, mean age 61 years). The most frequent entities were adenoid cystic carcinoma (n = 13, 14.3%) and mucoepidermoid carcinoma (n = 12, 13.2%). Kaplan-Meier analysis demonstrated a five-year overall survival (OS) of 66.2% and a recurrence-free survival (RFS) of 50.5%. Age > 60 years (p = 0.011), categorization into high-risk group (p = 0.011), UICC stage (p = 0.020), T stage (p = 0.032), grading (p = 0.045) and vascular invasion (p < 0.001) were significantly associated with OS; age > 60 years (p = 0.014), categorization into high-risk group (p < 0.001), UICC stage (p = 0.021), T stage (p = 0.017), grading (p = 0.011), vascular invasion (p = 0.012) and lymphovascular invasion (p < 0.001) were significantly associated with RFS. Multivariate Cox regression with backward elimination identified T stage (HR 1.835; 95% CI 1.187-2.836; p = 0.006) and grading (HR 2.233; 95% CI 1.113-4.480; p = 0.024) as significant factors for OS. Grading (HR 2.499; 95% CI 1.344-4.648; p = 0.004) was confirmed as a significant factor for RFS.

CONCLUSION

Considering the risk of recurrence and distant metastasis in malignant salivary gland tumors, locoregional surgical control may not be sufficient and adjuvant therapies such as radiotherapy and/or systemic therapies should be considered.

Malignant and Benign Tracheobronchial Neoplasms: Comprehensive Review with Radiologic, Bronchoscopic, and Pathologic Correlation

Tracheobronchial neoplasms are much less common than lung parenchymal neoplasms but can be associated with significant morbidity and mortality. They include a broad differential of both malignant and benign entities, extending far beyond more commonly known pathologic conditions such as squamous cell carcinoma and carcinoid tumor. Airway lesions may be incidental findings at imaging or manifest with symptoms related to airway narrowing or mucosal irritation, invasion of adjacent structures, or distant metastatic disease. While there is considerable overlap in clinical manifestation, imaging features, and bronchoscopic appearances, an awareness of potential distinguishing factors may help narrow the differential diagnosis. The authors review the epidemiology, imaging characteristics, typical anatomic distributions, bronchoscopic appearances, and histopathologic findings of a wide range of neoplastic entities involving the tracheobronchial tree. Malignant neoplasms discussed include squamous cell carcinoma, malignant salivary gland tumors (adenoid cystic carcinoma and mucoepidermoid carcinoma), carcinoid tumor, sarcomas, primary tracheobronchial lymphoma, and inflammatory myofibroblastic tumor. Benign neoplasms discussed include hamartoma, chondroma, lipoma, papilloma, amyloidoma, leiomyoma, neurogenic lesions, and benign salivary gland tumors (pleomorphic adenoma and mucous gland adenoma). Familiarity with the range of potential entities and any distinguishing features should prove valuable to thoracic radiologists, pulmonologists, and cardiothoracic surgeons when encountering the myriad of tracheobronchial neoplasms in clinical practice. Attention is paid to any features that may help render a more specific diagnosis before pathologic confirmation. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Pediatric primary salivary gland tumors

OBJECTIVES

To characterize the presentation and treatment of children presenting with primary salivary gland neoplasms.

METHODS

A retrospective review of primary salivary tumor patients presenting to Children's Hospital Colorado between January 2000 and August 2020.

RESULTS

Fifty children were identified with primary salivary gland tumors, comprising of 39 (78 %) benign and 11 (22 %) malignant lesions. Pleomorphic adenoma was the most common benign tumor (36/39, 92 %), while acinic cell carcinoma was the most common malignancy (7/11, 64 %). The parotid gland was the most common site, followed by the submandibular gland (66 % vs. 34 %). No tumors were found in the sublingual glands. Benign neoplasms accounted for 70 % of parotid lesions and 94 % of submandibular tumors. No significant differences in age (13.6 years, SD 4 vs. 13.0 years, SD 4.3) were noted between patients with benign and malignant disease, but tumors in females were more frequently malignant (M:F 1:1.3 vs. 1:2.7 for benign and malignant tumors, respectively). Neck dissection and/or facial nerve sacrifice were required in 27 % (3/11) and 9.1 % (1/11) of malignancies, respectively. Local recurrence was observed in 7.7 % (3/39) of benign cases and 9.1 % (1/11) of malignant cases. No salivary malignancies required chemotherapy, though one patient with neurofibromatosis received imatinib prior to resection. Two patients with locoregional malignancy received adjunctive radiation. The average duration of follow up for benign and malignant disease were 12.6 ± 25 and 45.1 ± 32 months, respectively.

CONCLUSIONS

This study presents one of the larger single institutional experiences of pediatric primary salivary neoplasms in the past 20 years, identifying pleomorphic adenoma and acinic cell carcinoma as the most common benign and malignant etiologies, respectively. While this review found most neoplasms presented as a localized mass effectively managed with conservative surgical resection, aggressive tumors required multidisciplinary care.

Single-cell RNA sequencing reveals tumor heterogeneity within salivary gland pleomorphic adenoma: A preliminary study

BACKGROUND

Salivary gland pleomorphic adenoma (SPA) is a common neoplasm of salivary glands that displays remarkable histological diversity. Previous studies have demonstrated the involvement of gene rearrangements and cytoskeleton-remodeling-related myoepithelial cells in SPA tumorigenesis. Cytoskeleton remodeling is necessary for epithelial-mesenchymal transition (EMT), a key process in tumor progression. However, the heterogeneity of tumor cells and cytoskeleton remodeling in SPA has not been extensively investigated.

METHODS

An analysis of single-cell RNA sequencing (scRNA-seq) was performed on 27 810 cells from two donors with SPA. Bioinformatic tools were used to assess differentially expressed genes, cell trajectories, and intercellular communications. Immunohistochemistry and double immunofluorescence staining were used to demonstrate FOXC1 and MYLK expression in SPA tissues.

RESULTS

Our analysis revealed five distinct cell subtypes within the tumor cells of SPA, indicating a high level of intra-lesional heterogeneity. Cytoskeleton-remodeling-related genes were highly enriched in subtype 3 of the tumor cells, which showed a close interaction with mesenchymal cells. We found that tumoral FOXC1 expression was closely related to MYLK expression in the tumor cells of SPA.

CONCLUSION

Tumor cells enriched with cytoskeleton-remodeling-related genes play a crucial role in SPA development, and FOXC1 may partially regulate this process.

Salivary gland neoplasms in small biopsies and fine needle aspirations

Salivary gland neoplasms are rare and represent a diverse group of head and neck tumors. Their diagnosis in limited cellularity specimens can be challenging as many of these have overlapping clinical, radiological presentation, and pathologic features. Fine needle aspiration and/or core biopsies are more of a norm than rarity to be performed preoperatively to provide invaluable information that can guide clinical management including surgery. Even though these limited specimens may not always provide a definitive diagnosis; they have high sensitivity in confirming primary neoplasia, assessing the tumor grade, and ruling out non-surgical disease. An algorithmic pattern based approach can help narrow the differential diagnosis; leading to a definitive diagnosis with the help of specific ancillary studies.