The many faces of acinic cell carcinomas of the salivary glands: a study of 40 cases relating histological and immunohistological subtypes to clinical parameters and prognosis

High-Grade Transformation and Carcinosarcoma: A Review of Two Forms of Advanced Progression in the Salivary Gland

CONTEXT.—

High-grade transformation, previously known as dedifferentiation, in salivary gland carcinoma and carcinosarcoma ex pleomorphic adenoma is a rare phenomenon. It is, however, clinically relevant and affects treatment and prognosis.

OBJECTIVE.—

To review the existing literature, describe the histologic and immunophenotypic features, and highlight the diagnostic criteria of high-grade transformation in various salivary gland carcinomas and carcinosarcomas; to review its effect on clinical presentation and prognosis; and to review relevant molecular characteristics and recent concepts and advances.

DATA SOURCES.—

Literature search in PubMed using key words such as "high-grade transformation," "dedifferentiation," and "carcinosarcoma" in salivary gland. Relevant articles were reviewed, and additional articles were curated from the references of these articles.

CONCLUSIONS.—

High-grade transformation occurs rarely but has a significant impact on prognosis and management. By microscopy, the high-grade area is usually a distinct nodule and shows solid and nested architecture, cellular atypia, high mitotic count, and necrosis. The molecular features are not well established. Carcinosarcoma almost always arises in a pleomorphic adenoma and likely follows an adenoma-carcinoma-sarcoma pathway.

Successful endotracheal intervention for primary tracheal acinic cell carcinoma: A case report and literature review

INTRODUCTION

Primary tracheal acinic cell carcinoma (ACC) is an exceptionally rare malignancy, posing challenges in understanding its clinical behavior and optimal management. Surgical resection has traditionally been the primary treatment modality, but we present a compelling case of tracheal ACC managed with endotracheal intervention, challenging conventional approaches.

PATIENT CONCERNS

A 53-year-old woman presented with shortness of breath, cough, and hemoptysis. Enhanced computed tomography revealed an obstructive tracheal lesion, leading to her referral for further assessment.

DIAGNOSIS

Microscopic evaluation, immunohistochemistry, and clinical assessments confirmed primary tracheal ACC, an exceedingly rare condition with limited clinical insights.

INTERVENTIONS

We utilized rigid bronchoscopy to perform endotracheal intervention, successfully resecting the tumor and restoring tracheal patency. Postoperatively, the patient received no radiotherapy or chemotherapy.

OUTCOMES

The patient achieved complete recovery, with 24-month follow-up examinations indicating no recurrence or metastatic disease. Only minimal scar tissue remained at the resection site.

CONCLUSION

This case demonstrates the potential of endotracheal intervention as a curative approach for primary tracheal ACC, minimizing invasiveness and preserving tracheal function. Collaborative research efforts and extensive case reporting are crucial for advancing our understanding of this rare malignancy and optimizing treatment strategies for improved patient outcomes.

Prognostic Impact of Tumor Immune Microenvironment and Its Predictive Role in Salivary Gland Cancer

BACKGROUND

Recently, many studies have investigated the role of tumor immune microenvironment (TIME) in carcinogenesis, highlighting its relation to both tumor regression and progression. In particular, the "inflammatory system", made of innate and adaptive immune cells, interacts with cancer cells and their surrounding stroma. In this setting, the aim of this review is to summarize the current literature regarding the TIME of major salivary gland carcinomas (MSGCs), with particular attention on the characteristics and prognostic role of tumor infiltrating lymphocytes (TILs), the mechanisms that lead to TILs exhaustion and the important additional immune infiltrating factors that help SGC progression or remission.

METHODS

A comprehensive literature search was performed concerning published articles on the role of TIME in MSGCs.

RESULTS

In this work we summarize the advancing knowledge on TIME in SGCs by demonstrating the key prognostic and/or predictive value of specific immune features.

CONCLUSION

From the analysis of the current 'status of the art' it clearly emerges a need for precise, unambiguous phenotyping of immune cell populations, as well as a more thorough understanding of the frequencies and interactions of multiple immune cell types inside the TIME and their spatial localization (intratumoral vs. stromal).

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Prognostic Assessment and Risk Stratification in Patients With Postoperative Major Salivary Acinar Cell Carcinoma

OBJECTIVE

To investigate the clinicopathological features and prognosis of postoperative major salivary acinar cell carcinoma (MSACC) and develop a prognostic model.

STUDY DESIGN

Retrospective cohort analysis of a public database.

SETTING

Patients with MSACC were identified from the Surveillance, Epidemiology, and End Results database (1975-2019).

METHODS

Overall survival (OS) was evaluated using Kaplan-Meier curves and a log-rank test. Univariate and multivariate Cox analyses were performed to explore independent prognostic factors. The prognostic model was constructed using screened variables and further visualized with a nomogram and web calculator, and assessed by concordance index, the area under the curve, calibration curve, and decision-making curve analysis.

RESULTS

An upward trend in the incidence of MSACC was observed throughout the study period. A total of 1398 patients were enrolled (training cohort: 978; validation cohort: 420), and the 5- and 10-year OS rates were 97.7% and 81.6%, respectively. Age, marital status, sex, histological grade, T stage, and lymph node status were identified as prognostic factors for OS. A novel nomogram was developed and showed excellent discrimination and clinical applicability. Additionally, a web calculator was designed to dynamically predict patient survival. Based on the nomogram-based score, a risk stratification system was constructed to distinguish patients with different risks. The OS of high-risk patients was significantly lower than that of the low-risk subgroup.

CONCLUSION

Long-term survival in postoperative MSACC was influenced by 6 prognostic factors. The proposed model enables individualized survival prediction and risk stratification, prompting us to be vigilant in high-risk subgroups and consider timely adjustment of subsequent treatment.

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

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

Malignant Myoepithelioma of the Head and Neck: Demographics, Clinicopathological Characteristics, Treatment, and Prognosis

Malignant myoepithelioma of the head and neck (HNMM) is a rare malignancy, and its characteristics and survival rates have not been well-defined. This study aimed to define the epidemiology of HNMM and identify the prognostic factors associated with the disease. Data on all patients diagnosed with HNMM between 1991 and 2016 were gathered from the Surveillance Epidemiology and End Results (SEER) database. The demographics, clinicopathological characteristics, treatment, and prognoses of the patients were described. Cox regression analysis was used to identify the prognostic factors, and the prognostic nomograms for overall survival (OS) and disease-specific survival (DSS) were constructed. A total of 333 cases of HNMM were identified. The average age at diagnosis was 60.6 years, and 50.1% of the patients were men. After diagnosis, 46.2% of patients underwent surgery alone, 43.5% of patients underwent surgery and radiotherapy, and 3.6% of patients received only radiotherapy. Survival analysis showed that the 5-year OS and DSS for all HNMM patients were 69.7 and 82.1%, respectively. In the multivariate analysis model, the undifferentiated pathological grade (P <0.05) and M1 in the M category (P <0.01) were independent prognostic factors for poor OS and DSS, whereas the use of surgical resection was an independent favorable prognostic factor for both OS and DSS (P <0.05). The prognostic nomograms for OS and DSS prediction were constructed; the C-index values for OS and DSS prediction were 0.78 (95% CI 0.70–0.86) and 0.79 (95% CI 0.67–0.90), respectively. In conclusion, this SEER data-based study demonstrated that HNMM patients often had a favorable prognosis, and distant metastasis, pathological grade, and the use of surgery contributed to their survival. Furthermore, we developed a prognostic nomogram to predict OS and DSS for HNMM patients to aid physicians in the clinical management of this rare disease.

Head & neck acinar cell carcinoma: a population-based study using the seer registry

Background

To explore the clinicopathologic characteristics, treatment and prognostic factors of head and neck acinar cell carcinoma (HNACC) comprehensively.

Methods

A population-based study was conducted using data from the Surveillance, Epidemiology, and End Results database (1975–2016). Overall survival (OS) and HNACC-specific survival of patients with different clinicopathologic variables were compared using the Kaplan-Meier method and Cox multivariate regression.

Results

A total of 2624 primary HNACC cases (1052 males, 1572 females) were identified. There was a significant difference in gender distribution. Among the total cohort, 2416 cases originated from salivary glands, including 2325 parotid gland ACC cases. Regardless of confounding factors, the 10-year and 20-year disease-specific survival (DSS) was 93.6 and 90%, respectively. Surgery was favourably associated with better DSS and OS [HR = 0.13, P = 0.0092 and HR = 0.23, P = 0.0203]. Gender was the only demographic independent prognostic factor for both DSS and OS [Male vs female, HR = 3.3, P = 0.0028 for DSS; HR = 2.44, P = 0.0376 for OS]. Higher pathological grade was adversely associated with DSS and OS [Grade II, HR = 4.03, P = 0.0444; Grade III + IV, HR = 35.64, P = 0.0000 for DSS; Grade III + IV, HR = 4.49, P = 0.0000 for OS, Grade I as reference]. In addition, TNM/AJCC stage was commonly associated with prognosis.

Conclusion

Surgery was the only favourable prognostic indicator for both DSS and OS. Gender, age, pathological differentiation and TNM/AJCC stage were independent prognostic factors for survival.

Primary Pulmonary Acinic Cell Carcinoma: A Clinicopathological Study of 6 Cases and Literature Review

Primary pulmonary acinic cell carcinoma (ACC) is rare. The clinicopathological features are not identical to that of classic ACC that leads to misdiagnosis. In this article, we summarized the clinicopathological features of 25 such cases, including 6 cases in this series and additional 19 cases in the literature. Pulmonary ACCs showed an overwhelming solid growth pattern. The neoplastic cells had eosinophilic granular and clear cytoplasm in most cases and displayed basophilic cytoplasm in only 4 cases. Intratumoral fibrous septa, mitotic figure, necrosis, and psammoma bodies were observed in some cases. Prominent nuclear atypia and perineural invasion might suggest high-grade transformation, metastasis, and recurrence. The tumor cells were strongly positive for CK8/18 and negative for TTF-1, p63, S-100, mammaglobin, MUC5b, MUC5ac, and DOG1. CK7 was exclusively positive for neoplastic cells with ductal differentiation. Of the 25 included cases, 10 cases were initially misdiagnosed. The tumor was prone to involve the right bronchus. The patient outcome was favorable. The accurate diagnosis of primary pulmonary ACC relies on comprehensive evaluation of histological and immunohistochemical features and realization of the difference from classic ACC.

Outcomes and prognostic factors for parotid acinic cell Carcinoma: A National Cancer Database study of 2362 cases

OBJECTIVES

To evaluate the demographics, clinical features, survival outcomes, and prognostic indicators of patients with acinic cell carcinoma (ACC) of the parotid gland with emphasis on the roles of grade, tumor size, and nodal status in survival.

MATERIALS AND METHODS

A retrospective analysis of cases diagnosed between 2004 and 2012 from the National Cancer Database was performed. Multivariable logistic regression was used to determine factors associated with survival.

RESULTS

2362 cases were identified. Most patients were females (61.3%) and Caucasian (85.4%) with a median age of 54 years (range, 18-90 years). Most tumors were <3 cm in size (75.8%). Regional metastases and high-grade histology were rare (8.2%, 5.1%). All patients received surgery as primary treatment with 42.7% of patients receiving adjuvant radiation therapy or chemoradiotherapy. 5 year overall survival was 88.6%. On multivariable analysis, age >70 years (hazard ratio [HR]: 10.05, 95% confidence interval [CI]: 5.64-17.91), high-grade (HR: 5.30, 95% CI: 3.39-8.29), tumor size of 3 to 6 cm (HR: 1.53, 95% CI: 1.10-2.12), tumor size >6 cm (HR: 2.98, 95% CI: 1.681-5.289), pN2+ (HR: 3.14, 95% CI: 2.10-4.69), T4 (HR: 2.89, 95% CI: 1.74-4.80) were significant prognosticators.

CONCLUSION

Although patients with ACC generally are considered to have a favorable prognosis, an aggressive subgroup with poor outcomes was identified. This group is characterized by high-grade, advanced T classification, tumors larger than 3 cm, with regional metastases and age greater than 70 years. Histologic grade is a substantially stronger predictor of survival than T and N classifications.

Clear cell changes in salivary gland neoplasms: A 20-year retrospective study

BACKGROUND

Clear cells are observed histopathologically in both benign and malignant neoplasms but their presence in salivary gland tumors has not been extensively documented.

MATERIAL AND METHODS

With IRB approval, the archive of the University of Florida College of Dentistry oral pathology biopsy service was retrospectively searched from 1994-2014 for all benign and malignant salivary tumors. Epidemiological data, tumor location and duration, and type of tumor were recorded. A four reviewer panel examined the original slides. Reviewers scaled each case as 0 (no clear cells present), 1 (few to focal clear cells), 2 (less than 50% clear cells), and 3 (greater than 50% clear cells).

RESULTS

A total of 535 cases were included of which 48% of tumors displayed 0 clear cells (257/535), 31.4% (168/535) scored 1, 13.6% (73/535) scored 2, and 7% (37/535) scored 3. Of the 251 (47%) malignant neoplasms, 64% (160/251) demonstrated 0-1 clear cell change, while 36% (91/251) showed a score of 2-3. For the total 284 (53%) benign tumors, 93% (265/535) scored 0-1 and 7% (19/535) scored a 2-3 range. No statistical difference was noted for gender, age, or duration of time present in regards to presence or absence of clear cells. Statistically significant differences in clear cell presence were found between location groups, between benign and malignant diagnosis, and between specific diagnostic groups.

CONCLUSIONS

This study demonstrates the frequent presence of increased numbers of clear cells in oral salivary malignancies and highlights salivary gland differential diagnoses when presented with clear cell changes.

Combined DOG1 and Mammaglobin Immunohistochemistry Is Comparable to ETV6-breakapart Analysis for Differentiating Between Papillary Cystic Variants of Acinic Cell Carcinoma and Mammary Analogue Secretory Carcinoma

BACKGROUND

We investigated the reliability of combined DOG1 and mammaglobin immunohistochemistry compared with ETV6 fluorescence in situ hybridization (FISH) in the assessment of salivary tumors previously diagnosed as acinic cell carcinoma (ACC). Ultrastructural features of cases reclassified as mammary analogue secretory carcinoma (MASC) were assessed by transmission electron microscopy (TEM).

METHODS

Immunohistochemical (IHC) reactivity to DOG1 and mammaglobin was validated against FISH targeting the ETV6 gene in all 14 cases.

RESULTS

Three cases with papillary cystic histomorphology previously diagnosed as ACC were revised to MASC. TEM features of the ETV6 rearrangement-positive MASC cases showed large numbers of secretory granules with extrusion into the intercellular spaces, well-developed endoplasmic reticulum, lipid-laden vacuoles, well-formed microvilli, and large lining cystic spaces.

CONCLUSIONS

Combined DOG1 and mammaglobin immunohistochemistry is comparable to ETV6 -breakapart analysis for differentiating between papillary cystic variants of ACC and MASC.

Salivary acinic cell carcinoma: reappraisal and update

Epidemiologic and clinicopathologic features, therapeutic strategies, and prognosis for acinic cell carcinoma of the major and minor salivary glands are critically reviewed. We explore histopathologic, histochemical, electron microscopic and immunohistochemical aspects and discuss histologic grading, histogenesis, animal models, and genetic events. In the context of possible diagnostic difficulties, the relationship to mammary analog secretory carcinoma is probed and a classification is suggested. Areas of controversy or uncertainty, which may benefit from further investigations, are also highlighted.

Disorders and tumors of the salivary glands in children

Salivary gland neoplasms are rare in children. In infants most tumors are benign hemangiomas, with some notable exceptions, such as sialoblastomas. An asymptomatic swelling in the periauricular region is the most common presenting complaint in older children. Approximately 50% of these lesions are malignant, which dictates a thorough diagnostic evaluation by a head and neck surgeon. Surgical excision is the primary treatment modality. Prognosis is primarily determined by histopathologic findings. This review discusses neoplastic lesions of the salivary glands in children, and malignant epithelial tumors in particular.

Review and Updates of Immunohistochemistry in Selected Salivary Gland and Head and Neck Tumors

Context

Immunohistochemistry is a useful tool for diagnosing salivary gland and head and neck tumors.

Objective

To review immunohistochemical markers, which can aid in the diagnosis of selected salivary gland and head and neck tumors.

Data Sources

Literature review and authors' personal practice experience.

Conclusions

Salivary gland and head and neck tumors include a large diverse group of tumors with complex and overlapping histologic features. Immunohistochemistry plays an important role in resolving the differential diagnosis of some salivary gland and head and neck tumors and can provide information for the prognosis of certain tumors.

Characterization of mammary analogue secretory carcinoma of the salivary gland: discrimination from its mimics by the presence of the ETV6-NTRK3 translocation and novel surrogate markers

Mammary analogue secretory carcinoma (MASC) is a recently recognized salivary gland tumor harboring an ETV6-NTRK3 translocation similar to secretory carcinoma of the breast. Histologically, MASC mimics papillary-cystic, microcystic, and follicular-type acinic cell carcinoma (AciCC) and low-grade cribriform cystadenocarcinoma (LGCCC) of the salivary gland. Using histology, immunohistochemistry (IHC), and molecular genetic techniques, we reevaluated 18 cases originally diagnosed as AciCC between 1993 and 2012. The last of these methods was used to detect the ETV6-NTRK3 translocation. The results reconfirmed 6 cases as AciCC (3 men; average age, 63 years) and helped us reclassify 10 cases as MASC (6 men; mean age, 46 years) and 2 as LGCCC (2 women; mean age, 48 years). Using IHC, we identified the 3 histologic types according to the expression patterns of vimentin, high-molecular-weight cytokeratin, cytokeratin 19, S-100, mammaglobin, MUC1, GATA-binding protein 3, adipophilin, α-amylase, DOG-1, SOX-10, and p63. The number of tumors diagnosed as MASC indicates that AciCC includes bona fide MASC cases. Because differential diagnosis among zymogen granule-poor AciCC, MASC, and LGCCC tumors is challenging, we recommend using molecular genetic tests for ETV6-NTRK3 for accurate diagnosis. Furthermore, detailed analyses of hematoxylin and eosin-stained tissues and IHC studies using the markers described here should be incorporated into routine practices.

Factors influencing survival in acinic cell carcinoma: a retrospective survival analysis of 2061 patients

BACKGROUND

Acinic cell carcinoma is an uncommon salivary neoplasm with clinical and histologic features known to influence prognosis. The purpose of this study was to further describe variables influencing survival in a large cohort of patients with acinic cell carcinoma.

METHODS

Using the Surveillance, Epidemiology, and End Results (SEER) registry, we obtained demographic, clinicopathologic, and treatment data pertaining to patients diagnosed with acinic cell carcinoma. Kaplan-Meier and Cox regression analyses were performed to compare survival with various clinical and pathological parameters.

RESULTS

We identified 2061 patients with acinic cell carcinoma from 1973 to 2009. Sex, staging, grade, subsite, and treatment were significant predictors of disease-specific survival (DSS). Patients who received surgery alone had the highest 20-year DSS (92.4%), followed by those treated with surgery and radiation (71.9%) or radiation alone (62.3%).

CONCLUSION

Our results suggest that histologic grade is a stronger predictor of survival than TNM classification, survival after surgical resection alone is excellent, and adjuvant radiation may be of limited benefit

Case-control analysis of survival outcomes in sinonasal acinic cell carcinoma

BACKGROUND

Acinic cell carcinoma (AciCC) is an uncommon malignant-epithelial salivary gland cancer. In very rare cases, this tumor may arise from sinonasal subsites, with only 19 cases described in the English-language literature.

METHODS

We performed a retrospective analysis of 18 cases of AciCC, obtained from searching the Surveillance, Epidemiology, and End Results (SEER) database between 1973 and 2009.

RESULTS

Patient demographics, including age, gender, and race, were similar to AciCC cases found in more common locations. However, all patients had low-grade tumors without regional or distant metastases. Comparing these patients to a stage, grade, and treatment-matched cohort of parotid AciCC, we found a lower 10-year overall survival (52.3%) with no significant difference in disease-specific survival (88.9%). Our meta-analysis of survival from cases in the literature estimated 10-year recurrence-free survival at 92.9%.

CONCLUSION

To our knowledge, this is the largest cohort of patients with AciCC reported in the English-language literature. Our results suggest that patients with sinonasal AciCC have excellent disease-specific survival, comparable to matched patients with AciCC in more common salivary gland subsites.

Prognostic factors associated with decreased survival in patients with acinic cell carcinoma

IMPORTANCE

Acinic cell carcinoma is a rare salivary neoplasm that is generally associated with a good prognosis, although a subset of patients develops local and distant recurrences. Given the rarity of the disease, factors to identify patients at risk for recurrences or decreased survival are not clearly defined.

OBJECTIVES

To identify clinicopathologic factors associated with adverse survival in patients with acinic cell carcinoma and to assess the effect of local, regional, and distant recurrences on survival.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective medical record review in a tertiary care cancer center of 155 patients treated for acinic cell carcinoma from January 1990 through February 2013.

MAIN OUTCOMES AND MEASURES

Primary outcomes evaluated were overall and disease-free survival. The end points assessed were age at diagnosis, sex, size of primary tumor, presence of positive surgical margins, postoperative radiation therapy, and development of local, regional, or distant recurrences.

RESULTS

The median survival was 28.5 years, with 13 patients (8.4%) dying of their disease. Women (n = 104) were affected twice as often as men (n = 51) but had an improved survival (P < .001). Patients diagnosed as having acinic cell carcinoma before or at the age of 45 years had an improved survival (P = .02) compared with their elder counterparts, a finding that was independent of sex. Neoplasms larger than 3 cm at presentation were associated with a decreased overall survival compared with smaller lesions (P = .02). The development of distant metastases was most associated with death from the disease (odds ratio, 49.90; 95% CI, 6.49-2246.30; P < .001) compared with local and regional recurrences.

CONCLUSIONS AND RELEVANCE

Although patients with acinic cell carcinoma generally have a favorable prognosis, we have identified several factors associated with decreased survival, including male sex, age older than 45 years, neoplasms larger than 3 cm, and the development of a distant recurrence. These results suggest that maximizing local and regional control for this disease can offer substantial benefit when no distant disease is detectable.

The prognostic impact of human leukocyte antigen (HLA) class I antigen abnormalities in salivary gland cancer. A clinicopathological study of 288 cases

AIMS

To study abnormalities of proteins of the major histocompatibility complex class I in a series of 288 salivary gland carcinomas, and to correlate findings with patients' overall survival (OS).

METHODS AND RESULTS

Protein expression of human leukocyte antigen (HLA)-A, heavy chain (HC)-10, β2 -microglobulin, low molecular weight polypeptides (LMP) 2 and 7, transporters associated with antigen processing (TAP) 1 and 2, calnexin, calreticulin, endoplasmic reticulum (ER) p57 and tapasin was evaluated by immunohistochemistry and semiquantitatively analyzed. As compared with normal salivary gland tissue, HLA-A, LMP7, TAP2 and HLA class I were significantly down-regulated in salivary gland carcinomas, whereas β2 -microglobulin, calnexin, LMP2, and TAP1 were upregulated. Expression of calreticulin, ERp57 and tapasin was unaltered. In univariate Kaplan-Meier analyses, low expression of LMP7 (P = 0.005) and high expression of β2 -microglobulin (P = 0.028), HLA-A (P < 0.001), TAP1 (P = 0.01), and tapasin (P < 0.001) were significantly associated with shorter OS. In multivariate analysis incorporating tumour stage, nodal/distant metastasis, and grade, HLA-A (P = 0.014), LMP7 (P = 0.033), and tapasin (P = 0.024), as well as distant metastasis (P = 0.012) and high tumour grade (P < 0.001), remained statistically significant.

CONCLUSION

The prognostic influence of up-regulated HLA-A and tapasin and down-regulated LMP7 may provide a rationale for targeting these specific components of the antigen processing and presentation pathway in salivary gland carcinomas.

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

Mammary analogue secretory carcinoma of salivary gland origin (MASC) is a recently described tumor with ETV6 translocation. Akin to secretory breast cancer, MASC expresses S-100 protein, mammaglobin, vimentin, and harbors a t(12;15) (p13;q25) translocation which leads to ETV6-NTRK3 fusion product. Histologically, MASC displays a lobulated growth pattern and is often composed of microcystic, tubular, and solid structures with abundant eosinophilic homogeneous or bubbly secretions. Colloid-like secretory material stains positive for periodic acid-Schiff (PAS) with and without diastase and for Alcian blue. The cells of MASC are devoid of PAS-positive secretory zymogen granules. These features help to exclude the most important differential diagnostic considerations, namely acinic cell carcinoma, low-grade cribriform cystadenocarcinoma, cystadenocarcinoma (not otherwise specified), and low-grade mucoepidermoid carcinoma. To date the presence of the ETV6-NTRK3 fusion gene has not been demonstrated in any other salivary gland tumor than MASC. It is likely that MASC is more common than currently recognized and with further studies, the clinical need for molecular studies of the ETV6-NTRK3 fusion may diminish. However, molecular testing is recommended at this time to arrive at the diagnosis of MASC.

Salivary gland carcinomas

INTRODUCTION

Salivary gland carcinomas are rare tumours of heterogeneous morphology that require distinctive surgical and adjuvant therapy.

METHODS

Relevant studies were electronically searched in PubMed and reviewed for innovative and important information.

RESULTS

Recent insights in genetic alterations like chromosomal aberrations, expression of receptor tyrosine kinases, malfunction of tumour suppressor genes or DNA promoter methylations increased the knowledge about aetiology and pathogenesis. New histological subtypes are recognised, and a three-tiered grading system seems reasonable. Ultrasound remains the basic diagnostic imaging procedure. New developments comprise the diffusion-weighed magnetic resonance imaging, while fluorodeoxyglucose positron emission tomography/computed tomography shows good diagnostic accuracy in detecting distant metastases and local recurrence. Fine-needle aspiration cytology helps in differentiating a neoplasia from a non-neoplastic lesion while being unreliable in recognising malignancy. In contrast, additional core needle biopsy and/or intraoperative frozen section diagnosis increase the accuracy in diagnosing a malignant lesion. Conservative parotid surgery with nerve monitoring remains state-of-the-art. Free flaps or musculoaponeurotic flaps are proposed for prevention of Frey's syndrome. As parotid cancer often shows skip metastases, complete ipsilateral neck dissection (level I-V) is indicated particularly in high-grade lesions. Adjuvant radio(chemo)therapy increases local tumour control, whereas overall survival is not necessarily improved. Current results of systemic chemotherapy or targeted therapy in advanced tumour stages are disappointing.

CONCLUSION

Despite several developments, salivary gland carcinomas remain a heterogeneous group of tumours challenging both pathologists and clinicians.