An update on grading of salivary gland carcinomas

UM-HACC-2A: MYB-NFIB fusion-positive human adenoid cystic carcinoma cell line

OBJECTIVES

Limited availability of validated human adenoid cystic carcinoma (ACC) cell lines has hindered the mechanistic understanding of the pathobiology of this malignancy and the development of effective therapies. The purpose of this work was to generate and characterize a human ACC cell line.

MATERIAL AND METHODS

Immediately after surgery, a tumor fragment from a minor salivary gland from the tongue of a female Caucasian was minced, dissociated, and a single cell suspension was plated in fibronectin-coated flasks. A culture medium containing bovine brain extract and rhEGF was optimized for these cells. Whole exome sequencing was used to evaluate the presence of MYB-NFIB translocation.

RESULTS

The University of Michigan-Human Adenoid Cystic Carcinoma (UM-HACC)-2A cells showed continuous growth in monolayers for at least 180 in vitro passages while maintaining epithelial morphology. Short-tandem repeat (STR) profiling confirmed a 100% match to patient DNA. Whole exome sequencing revealed the presence of the MYB-NFIB fusion in UM-HACC-2A cells, which was confirmed by PCR analysis. Western blots revealed high expression of epithelial markers (e.g. E-cadherin, EGFR, pan-cytokeratin) and proteins associated with ACC (e.g. c-Myb, p63). Developmental therapeutic studies showed that UM-HACC-2A cells were resistant to cisplatin (IC₅₀ = 44.7 µM) while more responsive to paclitaxel (IC₅₀ = 0.0006 µM). In a pilot study, we observed that UM-HACC-2A cells survived orthotopic transplantation into the submandibular gland. Notably, one of the mice injected with UM-HACC-2A cells exhibited lung metastasis after 6 months.

CONCLUSION

UM-HACC-2A is a MYB-NFIB fusion-positive ACC cell line that is suitable for mechanistic and developmental therapeutics studies.

Zebrafish blastomere screen identifies retinoic acid suppression of MYB in adenoid cystic carcinoma

Adenoid cystic carcinoma (ACC) is a salivary gland malignancy that has no effective therapy and is caused by translocations involving MYB. A zebrafish chemical genetic screen identifies the retinoic acid class of compounds as potential MYB-inhibitory agents. Preclinical ACC mouse xenotransplantation models confirm the in vivo efficacy of retinoic acid, which represents a potential therapy for ACC.

Pluripotent cells have been used to probe developmental pathways that are involved in genetic diseases and oncogenic events. To find new therapies that would target MYB-driven tumors, we developed a pluripotent zebrafish blastomere culture system. We performed a chemical genetic screen and identified retinoic acid agonists as suppressors of c-myb expression. Retinoic acid treatment also decreased c-myb gene expression in human leukemia cells. Translocations that drive overexpression of the oncogenic transcription factor MYB are molecular hallmarks of adenoid cystic carcinoma (ACC), a malignant salivary gland tumor with no effective therapy. Retinoic acid agonists inhibited tumor growth in vivo in ACC patient–derived xenograft models and decreased MYB binding at translocated enhancers, thereby potentially diminishing the MYB positive feedback loop driving ACC. Our findings establish the zebrafish pluripotent cell culture system as a method to identify modulators of tumor formation, particularly establishing retinoic acid as a potential new effective therapy for ACC.

Evaluation of Glypican-3 expression in benign and malignant salivary gland tumors

Introduction

Glypican-3 (GPC3) is involved in regulation of cell proliferation and morphogenesis. It is abundant in embryonic tissue, but limited in most adult tissues. GPC3 deletion or mutation can disturb the balance between cell apoptosis and proliferation, which may result in tumorigenesis. This study aimed to investigate the GPC3 expression in salivary gland tumors (SGTs) and the adjacent non-neoplastic tissues.

Methods

This study reviewed 50 samples of salivary tumors from the archive of Khalili Hospital, Shiraz, Iran, including 17 cases of pleomorphic adenoma (PA), 16 cases of mucoepidermoid carcinoma (MEC), and 17 cases of adenoid cystic carcinoma (ACC); as well as a control group of 23 cases of normal salivary gland tissues. GPC3 expression was investigated through immunohistochemistry.

Results

GPC3 expression was significantly higher in malignant tumors (MEC and ACC) than in PA, and higher in PA than in the normal salivary glands (P < 0.001). The expression intensity was moderate to strong in malignant tumors and weak to moderate in benign tumors. No strong positivity was observed in normal salivary gland tissues (P < 0.001). Nor was any association detected between the GPC3 expression and intensity with the clinicopathologic parameters.

Conclusion

Although GPC3 overexpression was observed at the protein level in SGTs, and its expression was not related with the clinicopathologic factors, the potential use of GPC3 for diagnostic, therapeutic, and prognostic purposes requires further investigations.

A rare case of endobronchial mucoepidermoid carcinoma of the lung presenting as non-resolving pneumonia

Background

Mucoepidermoid carcinoma (MEC) is the most common malignant salivary gland tumor, and MECs of the lung are rare, accounting for 0.1–0.2% of malignant lung tumors. Pulmonary MECs are commonly found in the segmental or lobar bronchi, rarely presenting as endobronchial lesions.

Case presentation

Here we describe the case of a 21-year-old female with no comorbid conditions who presented at the emergency room with a cough, yellow phlegm, pleuritic chest pain, and a subjective fever. These symptoms had been present for approximately one week prior to the patient's arrival at the hospital. A chest X-ray revealed right lower lobe alveolar infiltrate and computed tomography of the chest showed dense consolidation of the right lower lobe with ovoid intraluminal density in the right main stem bronchus. Upon fiber optic bronchoscopy, an endobronchial lesion was found in the right main stem sparing the right upper lobe uptake. Endobronchial biopsy results was consistent with MEC of the lung. The patient underwent a bilobectomy with complete resection of the tumor.

Conclusion

Endobronchial MEC is a rare type of salivary gland tumor. Patients with low-grade MECs have a good prognosis, whereas those with high-grade MECs, which are aggressive and associated with metastatic disease, have a poor prognosis. However, early identification and surgical resection can result in a good prognosis.

Ceruminous Neoplasms of the Ear

Ceruminous glands are modified apocrine glands located in the external auditory canal (EAC). Neoplastic lesions arising from these glands are rare in humans and constitute a major differential diagnosis for glandular neoplasms of the EAC. Due to anatomic restrictions, benign and malignant neoplasms present with similar symptoms and to some extent even comparable radiologic features, particularly when the tumors are localized. Biopsies are frequently limited by small size, fragmentation and improper anatomic and architectural orientation, thereby hampering our ability to appreciate the relationship of peripheral edges of the tumor to the surrounding tissue. Benign and malignant tumors may also have overlapping histomorphologic features, which further magnifies the challenges in accurate diagnosis and management strategies. This article summarizes the salient clinical, radiologic and histologic features of common ceruminous gland tumors, in addition to discussing features that can aid in differentiating ceruminous tumors from other EAC tumors and to distinguish benign from malignant entities.

Prognostic significance of histopathology in canine anal sac gland adenocarcinomas: Preliminary results in a retrospective study of 39 cases

Metastatic rates and survival times of canine anal sac gland adenocarcinomas (ASGACs) vary among studies, making prognostication difficult. Little is known about the prognostic significance of histopathology of ASGACs. This retrospective study investigated associations between histological features, clinical presentation and outcome for 39 ASGACs. Most tumours were incompletely excised (62%) and had moderate to marked peripheral infiltration (74%). The predominant growth pattern was solid, tubules/rosettes/pseudorosettes and papillary in 49%, 46% and 5% of the cases, respectively. Nuclear pleomorphism was either moderate (77%) or mild (23%). Necrosis and lymphovascular invasion were present in 54% and 10% of the cases, respectively. All histological features except mitotic count and necrosis were associated with nodal metastasis at presentation. A statistically significant poorer outcome was identified for tumours with a solid growth pattern, moderate or marked peripheral infiltration, necrosis and lymphovascular invasion. These results need further validation in a larger cohort of dogs.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

A Comparative Study of Primary Adenoid Cystic and Mucoepidermoid Carcinoma of Lung

Background

Pulmonary mucoepidermoid carcinoma (PMEC) and pulmonary adenoid cystic carcinoma (PACC) are the two major types of primary salivary gland-type (PSGT) lung cancers. The demographic profile, clinicopathological features, and predictors of survival as an overall group have not been described for PSGT cancers of lung.

Methods

In this study, we analyzed demographic, clinical, and survival data from 1,032 patients (546 PMEC and 486 PACC) who were diagnosed of PSGT lung cancer in the Surveillance, Epidemiology and End Results database from 1973 to 2014.

Results

The PSGT constituted 0.09% of all lung cancers with age-adjusted incidence rate of 0.07 per 100,000 person-years and change of −32% from 1973 to 2014. The incidence of PMEC was slightly higher than PACC but there were no differences in the age and sex distribution. PACCs (55%) were significantly higher at trachea and main bronchus while PMECs were more common at peripheral lungs (85%). Most of the tumors were diagnosed at an early stage and were low grade irrespective of histology. As compared to PMEC, significantly higher number of patients with PACC underwent radical surgery and received adjuvant radiation. The 1- and 5-year cause-specific survival was 76.6 and 62.8%, respectively. On multivariate analysis, the survival was affected by age at diagnosis, tumor stage, histological grade, period of diagnosis, and surgical resection. The histology showed strong interaction with time and hazard ratio of patients with PACC was significantly worse than patients with PMEC only after 5 years.

Conclusion

The incidence of pulmonary PSGT cancer is 7 cases per 10 million population in the United States and is decreasing. There was no difference between demographic profile of patients with PMEC and PACC but pathological features were diverse. The difference in the survival of patients with the two histological types surfaced only after 5 years when survival of patients with PMEC was better than PACC.

Incompletely treated malignancies of the major salivary gland: Toward evidence-based care

BACKGROUND

Unexpected malignancy is common in major salivary gland tumors due to variability of workup, creating challenging treatment decisions. The purpose of this study was to define treatment-related outcomes for patients with incompletely treated major salivary gland tumors.

METHODS

A retrospective cohort study was completed of patients with incompletely treated major salivary gland tumors. Tumor burden at presentation was established and treatment categorized. The Cox Proportional Hazards model was used to determine predictors of survival and failure.

RESULTS

Of the 440 included patients, patients with gross residual or metastatic disease had a worse overall survival (OS; P < .001). Presentation status was an independent predictor of OS on multivariate analysis (gross residual disease adjusted hazard ratio [HR_adjusted ] 2.55; 95% confidence interval [CI] 1.20-5.30; metastatic disease HR_adjusted 9.53; 95% CI 3.04-27.06).

CONCLUSION

Failure to achieve gross total resection during initial surgery resulted in worse OS. Adequate preoperative planning is required for initial surgical management to optimize tumor control and survival.

Salivary Gland Cancer Patient-Derived Xenografts Enable Characterization of Cancer Stem Cells and New Gene Events Associated with Tumor Progression

Purpose: Salivary gland cancers (SGC) frequently present with distant metastases many years after diagnosis, suggesting a cancer stem cell (CSC) subpopulation that initiates late recurrences; however, current models are limited both in their availability and suitability to characterize these rare cells.Experimental Design: Patient-derived xenografts (PDX) were generated by engrafting patient tissue onto nude mice from one acinic cell carcinoma (AciCC), four adenoid cystic carcinoma (ACC), and three mucoepidermoid carcinoma (MEC) cases, which were derived from successive relapses from the same MEC patient. Patient and PDX samples were analyzed by RNA-seq and Exome-seq. Sphere formation potential and in vivo tumorigenicity was assessed by sorting for Aldefluor (ALDH) activity and CD44-expressing subpopulations.Results: For successive MEC relapses we found a time-dependent increase in CSCs (ALDH⁺CD44^high), increasing from 0.2% to 4.5% (P=0.033), but more importantly we observed an increase in individual CSC sphere formation and tumorigenic potential. A 50% increase in mutational burden was documented in subsequent MEC tumors, and this was associated with increased expression of tumor-promoting genes (MT1E, LGR5, and LEF1), decreased expression of tumor-suppressor genes (CDKN2B, SIK1, and TP53), and higher expression of CSC-related proteins such as SOX2, MYC, and ALDH1A1. Finally, genomic analyses identified a novel NFIB-MTFR2 fusion in an ACC tumor and confirmed previously reported fusions (NTRK3-ETV6 and MYB-NFIB)Conclusions: Sequential MEC PDX models preserved key patient features and enabled the identification of genetic events putatively contributing to increases in both CSC proportion and intrinsic tumorigenicity, which mirrored the patient's clinical course. Clin Cancer Res; 24(12); 2935-43. ©2018 AACR.

Perineural Invasion in Parotid Gland Malignancies

Objectives To investigate the clinical predictors and survival implications of perineural invasion (PNI) in parotid gland malignancies. Study Design Case series with chart review. Setting Tertiary care medical center. Subjects and Methods Patients with parotid gland malignancies treated surgically from 2000 to 2015 were retrospectively identified in the Head and Neck Cancer Registry at a single institution. Data points were extracted from the medical record and original pathology reports. Results In total, 186 patients with parotid gland malignancies were identified with a mean follow-up of 5.2 years. Salivary duct carcinoma (45), mucoepidermoid carcinoma (44), and acinic cell carcinoma (26) were the most common histologic types. A total of 46.2% of tumors were found to have PNI. At the time of presentation, facial nerve paresis (odds ratio [OR], 64.7; P < .001) and facial pain (OR, 3.7; P = .002) but not facial paresthesia or anesthesia (OR, 2.8, P = .085) were predictive of PNI. Malignancies with PNI were significantly more likely to be of advanced T and N classification, be high-risk pathologic types, and have positive margins and angiolymphatic invasion. PNI positivity was associated with worse overall (hazard ratio, 2.62; P = .001) and disease-free survival (4.18; P < .001) on univariate Cox regression analysis. However, when controlling for other negative prognosticators, age, and adjuvant therapy, PNI did not have a statistically significant effect on disease-free or overall survival. Conclusions PNI is strongly correlated with more aggressive parotid gland malignancies but is not an independent predictor of worse survival. Facial paresis and pain were predictive of PNI positivity, and facial paresis correlated with worse overall and disease-free survival.

Adenoid cystic carcinoma evaluation and management: progress with optimism!

PURPOSE OF REVIEW

Adenoid cystic carcinoma (ACC) when diagnosed presents several diagnostic and treatment challenges. The standard treatment of surgery and postoperative radiotherapy has remained the standard of care for the past 3 decades. The purpose of this review is to update what's been reported and what's new since the last review in 2004.

RECENT FINDINGS

As accurate a histological diagnosis and staging of disease should be achieved prior to commencing any treatment. Patients' prognosis, in the long term, is determined by the finding of any solid tumour component in the examined excised specimen. The continued treatment of patients with ACC by surgery and postoperative radiotherapy has not changed in the long-term tumour-free outcome of patients. The majority of patients die because of loco-regional failure and/or distant metastases. Optimism is being generated by the findings at the molecular and genetic level of ACC giving hope that nonsurgical treatment can be complemented by novel treatments that will improve patients' disease cure and improved long-term survival.

SUMMARY

The histological grading determined by optical methods has not advanced our selection of treatment and new recent research findings on molecular and genetic factors give new hopes to changing the ACC classification, determining differing treatments and thus influencing an improved and prolonged tumour-free survival for more patients.

Intraoral Pigmented Low-Grade Adenocarcinoma, Not Otherwise Specified: Case Report and Immunohistochemical Study

Salivary adenocarcinoma, not otherwise specified (AdCaNOS) is a rare malignant tumor with potential diagnostic challenge, which mainly affects the parotid glands; however, the minor salivary glands can also be involved by AdCaNOS. This paper reports a case of a 45-year-old Afro-descendant woman complaining of a slow-growing mass with 6 months of evolution in the left superior vestibular fornix. Microscopic examination revealed an infiltrative epithelial neoplasm composed of predominantly solid growth pattern, arranged in a lobular configuration, admixed with glandular or ductal structures. Perineural invasion was evident. The tumor cells were polygonal or oval showing focally mild nuclear pleomorphism, and eosinophilic or clear cytoplasm. Notably, some areas exhibited intracytoplasmic pigment granules mainly in non-luminal cells, as well as sebaceous-like cells, discrete hyaline material deposition and foci of infiltration of residual salivary gland parenchyma. Tumor cells were negative for PAS, mucicarmine and Alcian blue stains. By immunohistochemistry, the tumor cells were diffuse and strongly positive for pan-cytokeratin (CK) AE1/AE3, 34betaE12 CK, vimentin, p63 and S100. CK7 and EMA strongly highlighted the ductal structures. Solid areas also showed diffuse and moderate expression of CD56. Podoplanin (D2-40), GFAP and Calponin, followed by DOG-1, were focally positive; whereas CK20, α-SMA, h-Caldesmon, CD57, ERBB2/HER2 and p53 were negative. Ki-67 was < 2%. Consecutive serial tissue sections using CD57 confirmed the perineural invasion. Positivity for HMB-45 and MART-1/Melan-A, as well as Fontana-Masson stain (and potassium permanganate bleaching-sensitive), identified the pigment granules as melanin. To the best of our knowledge, this is the first case of intraoral low-grade AdCaNOS with intracytoplasmic melanin granules.

Prognostic factors in head and neck mucoepidermoid carcinoma: experience at a single institution based on 64 consecutive patients over a 28-year period

Mucoepidermoid carcinoma (MEC) is the most common malignancy of the salivary glands. The clinical behaviour of MEC is largely unpredictable, ranging from indolent tumour growth to highly aggressive metastatic spread. The objective of this study was to determine the clinicopathological predictors of recurrence and survival in patients with head and neck MEC. The medical records of 64 patients who underwent surgical treatment for head and neck MEC between 1982 and 2010 were reviewed. The main outcome measures were disease-free survival (DFS) and overall survival (OS). Clinicopathological parameters evaluated were age, sex, anatomical subsite, histological grade, tumour stage, tumour size, adjuvant therapy, and nodal and margin status. For the entire cohort, the 5-year DFS was 82.8% and the 5-year OS was 67.2%. Histological grade and tumour subsite were statistically significant predictors of OS. Furthermore, tumour stage and nodal status were statistically significant predictors with respect to OS. Advanced tumour stage, high histological grade, submandibular/sublingual localization, and positive nodal status were independent predictors of the prognosis in patients with head and neck MEC. Further studies into the molecular biology of MEC are needed in order to provide new therapeutic strategies for patients with locally aggressive and highly metastatic carcinomas.

Margin Analysis: Malignant Salivary Gland Neoplasms of the Head and Neck

There are no established protocols for the optimum surgical margin required for salivary gland malignancies. Factors including histologic diagnosis and TNM stage have been shown to be important in prognosis and survival outcome and mandate special consideration of margin size. Salivary cancers are treated differently at different anatomic sites, and different histologic types show a propensity for major or minor glands. Low-grade malignancies are treated with soft tissue margins of 1 cm or less. The facial nerve is preserved unless infiltrated and encased. Adenoid cystic carcinoma and carcinoma ex pleomorphic adenoma require more complex planning to obtain negative margins.

Sclerosing Mucoepidermoid Carcinoma of the Submandibular Gland Presenting as Chronic Sialadenitis: A Case Report and Review of Literature

Sclerosing mucoepidermoid carcinoma of the salivary gland (SMEC) is a rare subtype of mucoepidermoid carcinoma (MEC), first described in 1987 by Chan and Saw. As far as we are aware, only 30 cases have been published since then. Most cases were located in the parotid gland with some cases described in the submandibular and minor salivary glands. SMEC typically presents as a long-standing mass, with a non-specific enhancing appearance on imaging and is often non-diagnostic on fine needle aspiration, making pre-operative diagnosis very difficult. It is characterised by dense sclerosis within an otherwise typical MEC, frequently with lymphoid proliferation and eosinophils at the periphery. The histological diagnosis of SMEC can be challenging, as the sclerosis may obscure the other morphological features, which can lead to misdiagnosis. Grading can also be difficult, and the prognostic value of grading for SMEC remains unclear. Herein is described a new case of SMEC, presenting clinically as chronic sialadenitis in the left submandibular gland of a 41 year old male. A brief literature review and the issues surrounding diagnosis and grading are also discussed.

How Phenotype Guides Management of the Most Common Malignant Salivary Neoplasms of the Larynx?

Salivary gland carcinomas of the larynx are uncommon. Adenoid cystic carcinoma is the most prevalent type of salivary gland carcinoma in this region, although other histologies such as mucoepidermoid carcinoma and adenocarcinomas have been reported. These tumors may present with advanced-stage due to nonspecific symptoms and their relatively slow-growing nature. The index of suspicion for a non-squamous cell carcinoma entity should be high when a submucosal mass is present. An accurate diagnosis is mandatory due to the impact each biologic entity has on treatment and outcome. Data concerning treatment and outcome are scarce, but primary surgery with utmost focus on free surgical margins is the treatment of choice. The role of adjuvant radiotherapy has not been well defined, although there is an agreement that it should be considered in advanced-stage or high-grade disease. This review considers only the most common malignant salivary neoplasms of the larynx with a focus on clinical management of these tumors.

Multidisciplinary Management of Salivary Gland Cancers

BACKGROUND

Salivary carcinomas are a rare group of biologically diverse neoplasms affecting the head and neck. The wide array of different histological entities and clinical presentations has historically limited attempts to establish well-defined treatment algorithms. In general, low-risk lesions can be managed with a single treatment modality, whereas advanced lesions require a more complex, multidisciplinary approach.

METHODS

The relevant literature was reviewed, focusing on diagnostic and treatment algorithms for salivary malignancies.

RESULTS

Salivary carcinomas with high-risk features require an aggressive treatment approach with complete surgical resection, neck dissection to appropriate cervical lymph-node basins, and postoperative radiotherapy.

CONCLUSIONS

The heterogeneity of salivary neoplasms represents a unique clinical challenge. Despite the multidisciplinary management paradigm detailed in this review, outcomes for advanced disease are unsatisfactory. Future progress will likely require the addition of novel systemic therapeutic strategies.

An Update on Tumors of the Lacrimal Gland

Lacrimal gland tumors are rare and constitute a wide spectrum of different entities ranging from benign epithelial and lymphoid lesions to high-grade carcinomas, lymphomas, and sarcomas with large differences in prognosis and clinical management. The symptoms and findings of a lacrimal gland lesion are a growing mass at the site of the lacrimal gland, including displacement of the eyeball, decreased motility, diplopia, and ptosis. Pain is the cardinal symptom of an adenoid cystic carcinoma. Radiological findings characteristically include an oval, well-demarcated mass for benign lesions whereas malignant lesions typically display calcifications, destruction of bone, and invasion of adjacent structures. The diagnosis ultimately relies on histology, as does the choice of treatment and the prognosis. In recent years, the understanding of the biology of numerous types of lacrimal gland neoplasia has improved and the choice of treatment has changed accordingly and holds further promise for future targeted therapies. Treatment of benign epithelial lesions is surgical excision whereas carcinomas often require adjuvant radiotherapy and/or chemotherapy. In contrast, the cornerstone in management of lymphoid lesions is chemotherapy, often including a monoclonal antibody. This article presents an update on the clinical, radiological, histological, and molecular features, along with treatment strategies for tumors of the lacrimal gland.

Diagnosis and Management of Malignant Salivary Gland Tumors of the Parotid Gland

Malignant parotid tumors are heterogeneous and diverse. Accurate diagnosis requires a pathologist familiar with the various histologic subtypes, immunohistochemistry stains, and common translocations. Clinical course varies according to tumor subtype, ranging from indolent, slow-growing adenoid cystic carcinoma to rapidly progressive, possibly fatal, salivary ductal carcinoma. Histologic grade is important in prognosis and therapy. Surgery remains the mainstay of treatment when negative margins can be achieved. Radiation improves locoregional control of tumors with high-risk features. Chemotherapy for parotid tumors can be disappointing. Studies of new targeted therapies have not offered significant benefits.

Two Different Cell Populations Is an Important Clue for Diagnosis of Primary Cutaneous Adenoid Cystic Carcinoma: Immunohistochemical Study

Primary cutaneous adenoid cystic carcinoma (PCACC) is a very rare malignancy. The differential diagnosis of PCACCs in pathology practice can be difficult and a group of primary and metastatic lesions, including adenoid basal cell carcinoma of the skin, should be considered in the differential diagnosis. Besides histomorphological clues, immunohistochemistry studies are very helpful in the differential diagnosis of PCACC. We report herein a case of PCACC with extensive immunohistochemical studies and review the literature from an immunohistochemistry perspective.

Patient-derived xenograft (PDX) tumors increase growth rate with time

Patient-derived xenograft (PDX) models are frequently used for translational cancer research, and are assumed to behave consistently as the tumor ages. However, growth rate constancy as a function of time is unclear. Notably, variable PDX growth rates over time might have implications for the interpretation of translational studies. We characterized four PDX models through several in vivo passages from primary human head and neck squamous cell carcinoma and salivary gland adenoid cystic carcinoma. We developed a mathematical approach to merge growth data from different passages into a single measure of relative tumor volume normalized to study initiation size. We analyzed log-relative tumor volume increase with linear mixed effect models. Two oral pathologists analyzed the PDX tissues to determine if histopathological feature changes occurred over in vivo passages. Tumor growth rate increased over time. This was determined by repeated measures linear regression statistical analysis in four different PDX models. A quadratic statistical model for the temporal effect predicted the log-relative tumor volume significantly better than a linear time effect model. We found a significant correlation between passage number and histopathological features of higher tumor grade. Our mathematical treatment of PDX data allows statistical analysis of tumor growth data over long periods of time, including over multiple passages. Non-linear tumor growth in our regression models revealed the exponential growth rate increased over time. The dynamic tumor growth rates correlated with quantifiable histopathological changes that related to passage number in multiple types of cancer.

Primary intraosseous adenoid cystic carcinoma of the mandible: a comprehensive review and analysis of four new cases with emphasis on morphologic, immunophenotypic, and molecular characteristics

OBJECTIVE

To comprehensively review the clinical manifestations, imaging, diagnosis, treatment, and pathologic features of primary intraosseous adenoid cystic carcinoma (PIACC) of the mandible and analyze PIACC histopathology and molecular features in four cases.

STUDY DESIGN

We reviewed the literature and retrospectively studied four cases of PIACC.

RESULTS

The clinical and imaging findings of PIACC are similar to other malignant or borderline-malignant mandible tumors. The four cases of PIACC included three males and one female (aged between 41 and 58 years). The histopathologic features of the tumors resembled those of ACC. We observed abundant osteoclasts resorbing bone at the leading edge of the tumors characterized by solid structure histology but not by the cribriform subtype. Additionally, all four cases showed abnormalities in the MYB gene and high expression of MYB protein. All patients survived for the duration of follow-up, and two patients had distant metastases (followed up for 3 to 36 months).

CONCLUSIONS

PIACC is extremely rare and is often clinically misdiagnosed. Different histologic subtypes could show different mechanisms of invasion of the mandible. MYB gene and protein expression abnormalities can be used as indicators for the precise diagnosis of PIACC.

Molecular Pathology: Predictive, Prognostic, and Diagnostic Markers in Salivary Gland Tumors

Although initial attempts at using ancillary studies in salivary gland tumor classification were viewed with skepticism, numerous advances over the past decade have established a role for assessment of molecular alterations in the diagnosis and potential prognosis and treatment of salivary gland tumors. Many monomorphic salivary tumors are now known to harbor defining molecular alterations, usually translocations. Pleomorphic, high-grade carcinomas tend to have complex alterations that are often further limited by inaccuracy of initial classification by morphologic and immunophenotypic features. Next-generation sequencing techniques have great potential in many aspects of salivary gland tumor classification and biomarker discovery.

Clinical and molecular insights into adenoid cystic carcinoma: Neural crest-like stemness as a target

OBJECTIVES

This review surveys trialed therapies and molecular defects in adenoid cystic carcinoma (ACC), with an emphasis on neural crest-like stemness characteristics of newly discovered cancer stem cells (CSCs) and therapies that may target these CSCs.

DATA SOURCES

Articles available on Pubmed or OVID MEDLINE databases and unpublished data.

REVIEW METHODS

Systematic review of articles pertaining to ACC and neural crest-like stem cells.

RESULTS

Adenoid cystic carcinoma of the salivary gland is a slowly growing but relentless cancer that is prone to nerve invasion and metastases. A lack of understanding of molecular etiology and absence of targetable drivers has limited therapy for patients with ACC to surgery and radiation. Currently, no curative treatments are available for patients with metastatic disease, which highlights the need for effective new therapies. Research in this area has been inhibited by the lack of validated cell lines and a paucity of clinically useful markers. The ACC research environment has recently improved, thanks to the introduction of novel tools, technologies, approaches, and models. Improved understanding of ACC suggests that neural crest-like stemness is a major target in this rare tumor. New cell culture techniques and patient-derived xenografts provide tools for preclinical testing.

CONCLUSION

Preclinical research has not identified effective targets in ACC, as confirmed by the large number of failed clinical trials. New molecular data suggest that drivers of neural crest-like stemness may be required for maintenance of ACC; as such, CSCs are a target for therapy of ACC.

Salivary Gland. Photon beam and particle radiotherapy: Present and future

Salivary gland cancers (SGCs) are rare diseases and their treatment depends upon histology, stage and site of origin. Radical surgery is the mainstay of treatment but radiotherapy (RT) plays a key role in both the postoperative and the inoperable setting, as well as in recurrent disease. In the absence of prospective randomized trials, a wide retrospective literature suggests postoperative RT (PORT) in patients with high risk pathological features. SGCs, and adenoid cystic carcinoma (ACC) in particular, are known to be radio-resistant tumors and should therefore respond well to particle beam therapy. Recently, excellent outcome has been reported with radical carbon ion RT (CIRT) in particular for ACC. Both modern photon- and hadron-based treatments are effective and are characterized by a favourable toxicity profile. But it is not clear whether one modality is superior to the other for disease control, due to the differences in patients' selection, techniques, fractionation schedules and outcome measurements among clinical experiences. In this paper, we review the role of photon and particle RT for malignant SGCs, discussing the difference between modalities in terms of biological and technical characteristics. RT dose and target volumes for different histologies (ACC versus non-ACC) have also been taken into consideration.

Expression of amphiregulin in mucoepidermoid carcinoma of the major salivary glands: a molecular and clinicopathological study

In mucoepidermoid carcinoma (MEC), CRTC1-MAML2 fusion indicates a favorable prognosis. Amphiregulin (AREG), an epidermal growth factor receptor (EGFR) ligand, has been shown to be a downstream target of CRTC1-MAML2 fusion, and to play a role in tumor growth and survival in CRTC1-MAML2-positive MEC cell lines. The aim of this study was to characterize the AREG and EGFR expression in the fusion-positive and fusion-negative MEC of the major salivary gland. The AREG and EGFR expression were studied by immunochemistry in 33 MEC cases of the major salivary glands. CRTC1-MAML2 fusion was tested by reverse-transcription polymerase chain reaction (23 CRTC1-MAML2 fusion-positive, 10 fusion-negative). Of 23 fusion-positive cases, AREG and EGFR overexpression were detected in 17 (73.9%) and 14 (60.9%) cases, respectively. Of 10 fusion-negative cases, AREG and EGFR overexpression were detected in 1 (10%) and 3 (30.0%) cases, respectively. There was a positive correlation between CRTC1-MAML2 fusion and AREG overexpression (P < .01), but not between CRTC1-MAML2 fusion and EGFR overexpression. The AREG overexpression was associated with a longer disease-free survival of the MEC patients (P = .042), but EGFR overexpression was not. In this study, we showed that AREG overexpression was detected more frequently in the CRTC1-MAML2 fusion-positive tumors than in fusion-negative tumors. Detection of AREG expression may be useful for identifying CRTC1-MAML2-positive MECs and as a marker for favorable prognosis.

Thoracic Myoepithelial Tumors: A Pathologic and Molecular Study of 8 Cases With Review of the Literature

Thoracic myoepithelial tumors (MTs) are a rare group of tumors showing predominant or exclusive myoepithelial differentiation. They are poorly characterized from both a morphologic and genetic standpoint, in particular features that separate benign from malignant behavior. We examined the histologic and immunohistochemical features of 8 primary thoracic MTs and performed fluorescence in situ hybridization for EWSR1, FUS, PLAG1, and HMGA2, as well as several partner genes. Half (4/8) of the MTs occurred in large airways, and 3 had infiltrative borders. All cases showed immunoreactivity for epithelial markers, in conjunction with S100 protein or myogenic markers. MTs showed morphologic characteristics analogous to MTs at other sites, with no tumors having ductal differentiation. Necrosis and/or lymphovascular invasion was present in 5 cases, with mitotic activity ranging from 0 to 6 mitoses/2 mm² (mean 1). Metastases occurred in 2 cases, and no patients died of disease. Gene rearrangements were identified in half of the cases, with EWSR1-PBX1, EWSR1-ZNF444, and FUS-KLF17 fusions identified in 1 case each and 1 case having EWSR1 rearrangement with no partner identified. No cases were found to have HMGA2 or PLAG1 abnormalities. Compared with fusion-negative tumors, fusion-positive tumors tended to occur in patients who were younger (50 vs. 58 y), female (1:3 vs. 3:1 male:female ratio), and demonstrated predominantly spindle and clear cell morphology. Using a combined data set of our case series with 16 cases from the literature, poor prognosis was significantly correlated with metastases (P=0.003), necrosis (P=0.027), and ≥5 mitoses/2 mm²/10 high-power field (P=0.005). In summary, we identify a subset of thoracic MTs harboring rearrangements in EWSR1 or FUS, and our data suggest that necrosis and increased mitotic activity correlate with aggressive clinical behavior.

Targeting MDM2 for Treatment of Adenoid Cystic Carcinoma

PURPOSE

There are no effective treatment options for patients with advanced adenoid cystic carcinoma (ACC). Here, we evaluated the effect of a new small molecule inhibitor of the MDM2-p53 interaction (MI-773) in preclinical models of ACC.

EXPERIMENTAL DESIGN

To evaluate the anti-tumor effect of MI-773, we administered it to mice harboring three different patient-derived xenograft (PDX) models of ACC expressing functional p53. The effect of MI-773 on MDM2, p53, phospho-p53, and p21 was examined by Western blots in 5 low passage primary human ACC cell lines and in MI-773-treated PDX tumors.

RESULTS

Single-agent MI-773 caused tumor regression in the 3 PDX models of ACC studied here. For example, we observed a tumor growth inhibition index of 127% in UM-PDX-HACC-5 tumors that was associated with an increase in the fraction of apoptotic cells (P = 0.015). The number of p53-positive cells was increased in MI-773-treated PDX tumors (P < 0.001), with a correspondent shift in p53 localization from the nucleus to the cytoplasm. Western blots demonstrated that MI-773 potently induced expression of p53 and its downstream targets p21, MDM2, and induced phosphorylation of p53 (serine 392) in low passage primary human ACC cells. Notably, MI-773 induced a dose-dependent increase in the fraction of apoptotic ACC cells and in the fraction of cells in the G1 phase of cell cycle (P < 0.05).

CONCLUSIONS

Collectively, these data demonstrate that therapeutic inhibition of the MDM2-p53 interaction with MI-773 activates downstream effectors of apoptosis and causes robust tumor regression in preclinical models of ACC. Clin Cancer Res; 22(14); 3550-9. ©2016 AACR.

Mucinous Adenocarcinoma of the Salivary Gland: A Review of a Rare Tumor

OBJECTIVE

To describe the clinical, demographic, and prognostic features of salivary gland mucinous adenocarcinoma, a rare head and neck malignancy.

STUDY DESIGN

Population-based national cancer registry analysis.

SETTING

Academic medical center.

SUBJECTS AND METHODS

A review was performed with the National Cancer Database from 1998 to 2012. Demographic, clinical, and survival characteristics were compiled and analyzed. Cox multivariate regression was used to identify predictors of survival. Log-rank tests were used to test survival differences unless otherwise specified.

RESULTS

A total of 170 cases were identified. The most common site of involvement was the parotid gland. Rates of nodal and distant metastases were 45.9% and 10.6%, respectively. High histologic grade was associated with nodal disease (P < .001) and advanced-stage disease (P = .006). Overall 5- and 10-year survival rates were 60% and 44%, respectively. Multivariate analysis found tumor size ≥2 cm (hazard ratio, 22.6; 95% confidence interval: 4.06-126.09; P < .001) and distant metastases (hazard ratio, 17.6; 95% confidence interval: 3.75-82.68; P < .001) to predict poor outcomes.

CONCLUSIONS

Mucinous adenocarcinoma of the salivary gland is a rare otolaryngic cancer. Regional metastases and advanced stage are more common with high histologic grade. Tumor size and distant metastases negatively influence survival.

Cancers of major salivary glands

Major salivary gland malignancies are a rare but histologically diverse group of entities. Establishing the diagnosis of a malignant salivary neoplasm may be challenging because of the often minimally symptomatic nature of the disease, and limitations of imaging modalities and cytology. Treatment is centered on surgical therapy and adjuvant radiation in selected scenarios. Systemic therapy with chemotherapeutic agents and monoclonal antibodies lacks evidence in support of its routine use.

Expression of cell adhesion molecule CD44 in mucoepidermoid carcinoma and its association with the tumor behavior

Background

The most common malignant salivary gland tumors that affect both adult and children is mucoepidermoid carcinoma. It usually affects both minor and major salivary glands but parotid gland is considering the most common site in which this tumor arises. CD44, a trans-membrane glycoprotein, is an adhesion molecule of cell surface that play a role in the connections between cell-cell and cell-matrix. Many malignant tumors express high levels of CD44, thus, CD44 may be used as an indicator of aggressive behavior of some human malignancy. We evaluate CD44 expression in different grades of mucoepidermoid carcinoma and determine whether expression of CD44 can be used to predict tumor aggressiveness.

Methods

Fifteen cases of mucoepidermoid carcinoma were retrieved from the oral pathology archives and grouped according to the histological grade as well as the clinical behavior regarding metastases and/or recurrence. Tissue sections were immunohistochemically stained for CD44. CD44 staining was scored for intensity and proportion of cells stained.

Results

A higher proportion of high-grade tumor tissues showed moderate or strong CD44 staining compared to low-grade tumors. Additionally, CD44 expression was stronger in tumors from patients with recurrences or metastases, but theses differences were not statistically significant.

Conclusion

Our result showed that mucoepidermoid carcinomas are immunohistochemistry positive to CD44 compare to normal. A trend of CD44 expression associated with different histological grading and aggressive behavior of this tumor.

Preoperative cytological diagnosis of papillary cystic variant of acinic cell carcinoma: A key consideration in patient management

Preoperative diagnosis of malignant salivary gland tumors is difficult as radiological imaging procedures have low sensitivity rate for detecting malignancy in parotid gland tumors. With careful and detailed analysis of cytological features, guided fine needle aspiration cytology can prove to be a reliable diagnostic modality that can help in differential diagnosis of cystic parotid malignancies from cystic benign tumors and non-neoplastic lesions. Papillary cystic variant of acinic cell carcinoma is a rare, cystic, primary neoplasm of salivary gland that occurs commonly in parotid. The tumor shows high local recurrence rate and has poorer prognosis compared to classic acinic cell carcinoma. Preoperative cytological diagnosis of papillary cystic variant of acinic cell carcinoma of parotid, in the case described here was the basis for adequate and timely surgical management with good results.

MTA1 Expression in Benign and Malignant Salivary gland Tumors

INTRODUCTION

Salivary gland tumors (SGTs) are important parts of human neoplasms. The most common SGT is pleomorphic adenoma and the most common malignant SGTs are mucoepidermoid carcinoma and adenoid cystic carcinoma (ACC). Metastasis-associated genes 1 (MTA1), a member of the nucleosome remodeling and histone deacetylation complex, is one newly discovered gene which recruits histone deacetylation, causing ATP-dependent chromosome remodeling, and regulating transcription. MTA1 had been shown to be overexpressed in malignant tumors with the enhancement of invasion and metastasis.

MATERIALS AND METHODS

Fifty-six samples of salivary gland tumors from the Khalili Hospital archive, including 20 cases of pleomorphic adenoma, 17 cases of mucoepidermoid carcinoma, 19 cases of ACC, and 23 cases of normal salivary gland tissues were chosen for immunohistochemical analysis of MTA1.

RESULTS

MTA1 expression in the malignant tumors was significantly higher than that in pleomorphic adenoma (P<0.001), and higher in pleomorphic adenoma than the normal salivary glands(P< 0.001). In total, 69.6% of normal salivary gland tissues showed MTA1, but all cases of salivary gland tumors were positive for MTA1. High nuclear expression of MTA1 was detected in 83.3% (30/36) of the malignant salivary gland tumors and 45% (9/20) of pleomorphic adenoma, while low MTA1 expression was seen in all of the normal salivary gland tissues. No statistically significant correlation was found between MTA1 protein expression and any clinicopathological features (P>0.05).

CONCLUSION

Our findings demonstrate that MTA1 was significantly overexpressed in malignant salivary gland neoplasm in comparison to a lower level in benign pleomorphic adenoma, suggesting that MTA1 protein might be involved in carcinogenesis.

Outcomes and prognostic factors for major salivary gland carcinoma following postoperative radiotherapy

PURPOSE

To report outcomes of postoperative radiotherapy (PORT) for major salivary gland carcinoma (SGC) and identify patients at high risk of distant metastases (DM).

METHODS AND MATERIALS

Patients with major SGC treated between 2000-2012 were identified. All patients underwent initial primary resection, with neck dissection (ND) therapeutically (if N+) or electively in high risk N0 patients. PORT was delivered using 3D-CRT or IMRT. Multivariable analysis (MVA) assessed predictors for DM, cause-specific (CSS) and overall survival.

RESULTS

Overall 304 patients were identified: 48% stage III-IVB, 22% lymphovascular invasion (LVI), 50% involved margins and 64% high risk pathology. ND was performed in 154 patients (51%). Adjuvant chemotherapy was used in 10 patients (3%). IMRT was delivered in 171 patients (56%) and 3D-CRT in 133 (44%). With a median follow-up of 82 months, the 5-(10-) year local, regional, distant control, CSS and OS were 96% (96%), 95% (94%), 80% (77%), 83% (82%) and 78% (75%), respectively. DM was the most frequent treatment failure (n=62). On MVA, stage III-IVB and LVI significantly correlated with DM, CSS and OS, while positive margins predicted DM and CSS, and high risk pathology predicted DM. No grade ⩾ 4 RTOG late toxicity was reported; 9 patients had grade 3, including osteoradionecrosis (n=4), neck fibrosis (n=3), trismus (n=1) and dysphagia (n=1).

CONCLUSIONS

Surgery and PORT with 3D-CRT/IMRT produced excellent long-term outcomes. Further research is required for patients with stage III-IVB, LVI, positive margins and high risk pathology to determine the incremental benefit of systemic therapy in management of SGC.

Clinicopathological analysis of salivary gland tumors over a 15-year period

Salivary gland tumors (SGT) are rare neoplasms that generate interest due to their histopathological diversity and clinical behavior. The aims of the present study were to investigate clinicopathological aspects of SGTs diagnosed at a tertiary health center and compare the findings with epidemiological data from different geographic locations. Cases of tumor in the head and neck region at a single health center in the period between 1995 and 2010 were reviewed. Patient gender, age and ethnic group as well as anatomic location, histological type and clinical behavior of the tumor were recorded. Availability of complete information about these aspects was considered the inclusion criteria. Descriptive statistical analysis of the data was performed using the frequencies of categorical variables. Among the 2168 cases of tumors in the head and neck region, 243 (11.20%) cases were diagnosed in the salivary glands, 109 of which met the inclusion criteria: 85 (78%) benign tumors and 24 (22%) malignant tumors. Mean patient age was 46.47 years. The female gender accounted for 56 cases (51.4%) and the male gender accounted for 53 (48.3%). The major salivary glands were affected more (75.2%) than the minor glands. The most frequent benign and malignant SGTs were pleomorphic adenoma (81.2%) and adenoid cystic carcinoma (58.3%), respectively. In conclusion, pleomorphic adenoma and adenoid cystic carcinoma are the most frequent benign and malignant lesions, respectively. Comparing the present data with previous studies on SGTs, one may infer that some demographic characteristics and the predominance of malignant tumors vary in different geographic regions.

Characteristics of salivary gland tumours in the United Arab Emirates

Salivary gland tumours (SGT) are relatively rare cancers characterised by striking morphological diversity and wide variation in the global distribution of SGT incidence. Given the proximity to the head and neck structures, management of SGT has been clinically difficult. To the best of our knowledge, there are no epidemiological studies on SGT from the United Arab Emirates (UAE) or the Gulf Cooperation Council Countries (GCC). Patient charts (N = 314) and associated pathological records were systematically reviewed between the years 1998–2014. Predominance of benign (74%) compared with malignant (26%) SGT was observed. Among the 83 malignant SGT identified, frequency was higher in males (61%) than in females (39%) and peak occurrence was in the fifth decade of life. Mucoepidermoid carcinoma was the most common type of tumour (35%) followed by adenoid cystic carcinoma (18.1%) and acinar cell carcinoma (10.8%). A similar pattern of tumour distribution was seen in patients from GCC, Asian, and Middle East countries. This is the first report to address the distribution of salivary gland tumours in a multiethnic, multicultural population of the Gulf. The results suggest that the development of an SGT registry will help clinicians and researchers to better understand, manage, and treat this rare disease.

Predictors of Nodal Metastasis in Parotid Malignancies: A National Cancer Data Base Study of 22,653 Patients

OBJECTIVE

(1) To identify predictors of nodal disease in parotid malignancies using various clinical and pathologic variables. (2) To examine the effect of nodal disease on overall survival (OS) in parotid cancers

STUDY DESIGN

Retrospective database review.

SETTING

National Cancer Data Base (1998-2012).

SUBJECTS AND METHODS

We identified all cases of primary parotid malignancies in the United States between 1998 and 2012 in the National Cancer Data Base. Eight histopathologies, constituting >80% of all cases, were examined for nodal metastasis and survival.

RESULTS

We identified 22,653 cases of primary parotid cancer. Eight major histologies were studied, with mucoepidermoid carcinoma (31%), acinic cell carcinoma (18%), adenocarcinoma (14%), and adenoid cystic carcinoma (9%) being most common. Regional nodal disease incidence was 24.4% overall and varied by histopathology. Salivary ductal carcinoma had the highest incidence of both nodal metastasis and occult lymph node metastasis. Overall, N0 patients lived significantly longer than N+ (5-year OS, 79% vs 40%; P < .001). Low-grade disease had significantly better survival than high-grade (5-year OS, 88% vs 69%; P < .001). Occult nodal disease was found in 10.2% and varied by histopathology.

CONCLUSION

Regional lymph node metastasis significantly decreases survival in many parotid malignancies. High-grade cancers had higher incidences of regional disease than did low grade. Adenocarcinoma had the highest mortality when regional disease was present. Incidence of occult disease varied by histology, but incidence was <10% for all low-grade disease. High T stage and grade are significant independent predictors of nodal disease for most histopathologies.