Primary squamous cell carcinoma of the parotid gland

Tumour Recurrence, Depth of Invasion, and Temple Location as Independent Prognostic Parameters of Lymph Node Metastases of Head and Neck Cutaneous Squamous Cell Carcinomas

The excellent survival rate of cutaneous squamous cell carcinoma (cSCC) exceeding 90% is reduced by the presence of nodal metastases by over 50%. We analysed various risk parameters of cSCC to predict the incidence of nodal metastases. A total of 118 patients with the head cSCC were included in a single-institution retrospective study covering the period from 2008 to 2020. Tumour recurrence, temple location, and tumour infiltration depth were found to be independent predictors of nodal metastases (increasing the probability of metastases by 8.0, 8.1, and 4.3 times, respectively). Furthermore, univariate analysis shows that the tumour size and T stage are significant factors increasing the risk of metastases. Several independent risk factors for the development of metastases in the head cSCC have been confirmed. These findings might help identify at-risk patients who require additional attention for adequate radical treatment and close follow-up. In contrast, elective treatment of lymph nodes is not recommended due to the low incidence of regional metastases.

Parotid Gland Metastases of Cutaneous Squamous Cell Carcinoma of the Head: Occult Metastases Occurrence and Their Late Manifestation

Cutaneous squamous cell carcinomas (cSCC) are malignant tumours with excellent prognosis unless nodal metastases develop. The aim of our study is to determine the prognostic significance of the clinical stage of parotid gland metastases and the incidence of occult cervical lymph node involvement in cSCC of the head. Our retrospective analysis includes 39 patients with cSCC parotid gland metastases, 15 of whom had concurrent cervical node involvement. In 32 patients, the lymph nodes manifested at stage N3b. A total of 26 patients were treated with parotidectomy, 9 patients received radiotherapy alone, and 4 received symptomatic therapy. The surgical treatment included either total conservative (21 cases) or superficial parotidectomy (5 cases) and neck dissection (therapeutic neck dissections in 11 cases and elective in 14 cases). In all cases, surgery was performed with sufficient tumour-free resection margins. Adjuvant radiotherapy was administered postoperatively in 16 patients. Occult metastases were present in 21% of cases after an elective neck dissection, but not in any case in the deep lobe of the parotid gland. The five-year overall survival and recurrence-free interval were 52% and 55%, respectively. Patients with the cN3b stage and G3 histological grade tend to have a worse prognosis, but not at a statistically significant level. The prognosis was not worse in patients with concurrent parotid and cervical metastases compared to those with metastases limited to the parotid gland only. The addition of adjuvant irradiation, in comparison to a single modality surgical treatment, was the only statistically significant prognostic factor that reduced the risk of death from this diagnosis (p=0.013). The extent of parotidectomy (partial vs. total) had no impact on either the risk of recurrence or patient prognosis. The combination of surgery with irradiation provides the best results and should be applied to all patients who tolerate the treatment. A partial superficial parotidectomy should be sufficient, with a minimum risk of occult metastasis in the deep lobe. Conversely, the relatively high incidence of occult neck metastases indicates that patients could likely benefit from elective neck dissection.

Elective parotidectomy and neck dissection are not beneficial in cutaneous squamous cell carcinoma of the head

OBJECTIVE

Cutaneous Squamous Cell Carcinoma (cSCC), a tumor with a significantly increasing incidence, is mostly diagnosed in the head region, where tumors have a worse prognosis and a higher risk of metastases. The presence of metastases reduces specific five-year survival from 99% to 50%. As the risk of occult metastases does not exceed 10%, elective dissection of the tributary parotid and neck lymph nodes is not recommended.

METHODS

We retrospectively analyzed a group of 12 patients with cSCC of the head after elective dissections of regional (parotid and cervical) nodes by means of superficial parotidectomy and selective neck dissection.

RESULTS

We diagnosed occult metastases neither in the cervical nor parotid nodes in any patient. None were diagnosed as a regional recurrence during the follow-up period.

CONCLUCION

Our negative opinion on elective parotidectomy and neck dissection in cSCC of the head is in agreement with the majority of published studies. These elective procedures are not indicated even for tumors showing the presence of known (clinical and histological) risk factors for lymphogenic spread, as their positive predictive value is too low. Elective parotidectomy is individually considered as safe deep surgical margin. If elective parotidectomy is planned it should include only the superficial lobe. Completion parotidectomy and elective neck dissection are done in rare cases of histologically confirmed parotid metastasis in the parotid specimen. Preoperatively diagnosed parotid metastases without neck involvement are sent for total parotidectomy and elective selective neck dissection. Cases of clinically evident neck metastasis with no parotid involvement, are referred for comprehensive neck dissection and elective superficial parotidectomy. The treatment of concurrent parotid and cervical metastases includes total conservative parotidectomy and comprehensive neck dissection.

LEVEL OF EVIDENCE

How common is the problem? Step 4 (Case-series) Is this diagnostic or monitoring test accurate? (Diagnosis) Step 4 (poor or non-independent reference standard) What will happen if we do not add a therapy? (Prognosis) Step 4 (Case-series) Does this intervention help? (Treatment Benefits) Step 4 (Case-series) What are the COMMON harms? (Treatment Harms) Step 4 (Case-series) What are the RARE harms? (Treatment Harms) Step 4 (Case-series) Is this (early detection) test worthwhile? (Screening) Step 4 (Case-series).

Parotidectomy and neck dissection in locally advanced and relapsed cutaneous squamous cell carcinoma of the head and neck region

OBJECTIVE

To investigate the prognostic factors to developing parotid and neck metastasis in locally advanced and relapsed Cutaneous Squamous Cell Carcinoma (CSCC) of the head and neck region.

METHODS

Single-center retrospective cohort study enrolling consecutive patients with advanced CSCC from 2009 to 2019. Seventy-four cases were identified. Study variables demographic data, clinical skin tumor stage, neck stage, parotid stage (P stage), surgical treatment features, and parotid, regional, and distant metastases. Survival measures: Overall Survival (OS) and Disease-Specific Survival (DSS).

RESULTS

The study group included 72.9% men (median age, 67 years); 67.5% showed T2/T3 tumors, 90.5% comorbidities, 20.2% immunosuppressed, with median follow-up: 35.8 months. The most frequent skin primary were auricular and eyelid regions, 75% underwent primary resection with flap reconstruction. Parotid metastasis was present in 50%, 32.4% showing parotid extracapsular spread, multivariate analysis found OR = 37.6 of positive parotid metastasis evolving into positive neck metastasis, p = 0.001. Occult neck metastasis, neck metastasis, and neck extracapsular spread were observed in 13.5%, 51.3%, and 37.8%, respectively. Kaplan-Meier survival: Clinical T4 versus T1, p = 0.028, P1 stage: 30% and 5% survival at 5 and 10 years, P3 stage: 0%, p = 0.016; OS and DSS showed negative survival for the parotid metastasis group, p = 0.0283.

CONCLUSION

Our outcomes support a surgically aggressive approach for locally advanced and relapsed CSCC, with partial parotidectomy for P0, total parotidectomy for P1-3, selective I-III neck dissection for all patients and adjuvant radiochemotherapy to appropriately treat these patients with advanced CSCC of the head and neck region.

LEVEL OF EVIDENCE

II b - Retrospective Cohort Study - Oxford Centre for Evidence-Based Medicine (OCEBM).

Clinico-Epidemiological Analysis of Most Prevalent Parotid Gland Carcinomas in Poland over a 20-Year Period

(1) Background: Malignant tumours of the salivary glands have different clinical and histopathological characteristics. They most commonly involve the parotid gland. Histopathologically, the most common are mucoepidermoid carcinoma (MEC), adenoid cystic carcinoma (AdCC), acinic cell carcinoma (AcCC), adenocarcinoma, carcinoma in pleomorphic adenoma (CPA), and squamous cell carcinoma (SCC). (2) Methods: We analysed 2318 patients with malignant parotid gland tumours reported to the National Cancer Registry (NCR) in Poland over 20 years (1999-2018). The demographic characteristics of patients, clinical factors, and overall survival (OS) were analysed. (3) Results: The average age was 61.33 ± 16.1 years. The majority were males (55%) and urban citizens (64%). High percentage of carcinomas was diagnosed in locoregional (33.7%) and systemic (10.4%) stadium. The most prevalent diagnoses were SCC (33.3%) and adenocarcinoma (19.6%). Surgical resection with adjuvant RT (42.1%) was the most common treatment. The OS analysis showed a median survival time of 5.6 years. The most favorable median OS was found in patients with AcCC (18.30 years), the worst for SCC (1.58 years). (4) Conclusion: AcCC has the best prognosis and SCC the worst. Tumour stadium, treatment, and demographic factors affect prognosis. Improvements in diagnosis and re-evaluation of treatment standards are necessary to enhance the outcome of patients with parotid gland cancers in Poland.

Morphologic CT and MRI features of primary parotid squamous cell carcinoma and its predictive factors for differential diagnosis with mucoepidermoid carcinoma

Background

Primary parotid squamous cell carcinoma (SCC) is a rare entity with a poor prognosis. Pathologically, the diagnosis of it requires the exclusion of parotid mucoepidermoid carcinoma (MEC). Currently, the imaging features of primary parotid SCC and the predictive indicators for differential diagnosis of the two entities have not been well reported. Our purpose was to identify the imaging characteristics of primary parotid SCC and to determine the predictive factors for its’ differential diagnosis.

Results

Thirty-one participants with primary parotid SCC and 59 with primary parotid MEC were enrolled. Clinical, CT and MRI features were reviewed and compared by univariate analysis. Then, multinomial logistic regression was used to determine the predictors to distinguish parotid SCC from MEC. Most primary parotid SCCs exhibited irregular shape, ill-defined margin, incomplete or no capsule, heterogeneous and marked or moderate enhancement, necrosis, local tumor invasiveness (LTI). Age, maximal dimension, shape, degree of enhancement, gradual enhancement, necrosis, and LTI were different between the primary parotid SCCs and MECs in univariate analysis (p < 0.05). While in multinomial logistic regression analysis, only age and necrosis were the independent predictors for distinguishing parotid SCC from MEC, and this model exhibited an area under curve of 0.914 in ROC curve analysis.

Conclusions

Primary parotid SCC has some distinct imaging features including the large tumor size, irregular shape, ill-defined margin, and particularly the marked central necrosis. Patients with age ≥ 51.5 years and necrosis on the image of the primary tumor in the parotid gland could be more likely to be SCCs than MECs.

Nomogram-Based Prediction of Overall and Disease-Specific Survival in Patients With Postoperative Major Salivary Gland Squamous Cell Carcinoma

Background : The major salivary gland squamous cell carcinoma is a rare head and neck tumor, often accompanied by lymph node metastasis. Even if the patient undergoes surgery, the prognosis remains unsatisfactory. To explore the prognostic factors of postoperative major salivary gland squamous cell carcinoma to establish a prognostic risk stratification model to guide clinical practice. Methods: Patients’ information was retrieved from the Surveillance, Epidemiology, and End Results database from 2004 to 2018. Optimal cutoff points were determined using X-tile software, and overall survival and disease-specific survival were calculated by the Kaplan-Meier method. Independent prognostic factors affecting the overall survival and disease-specific survival were identified by multivariate analysis, and corresponding 2 nomogram models were constructed. The discriminative ability and calibration of nomograms were evaluated by the Concordance index, area under curves, and calibration plots. Results: A total of 815 patients with postoperative major salivary gland squamous cell carcinoma were enrolled. The cutoff values for the number of lymph nodes were 2, and the cutoff values for the lymph node ratio were 0.11 and 0.5, respectively. Age, T stage, tumor size, lymph nodes, lymph node ratio, and radiotherapy were prognostic factors for overall survival and disease-specific survival. Nomograms for disease-specific survival and overall survival were established and showed favorable performance with a higher Concordance index and area under curves than that of the tumor–node–metastasis stage and Surveillance, Epidemiology, and End Results stage. The calibration plots of 1-, 3-, and 5-year overall survival and disease-specific survival also exhibited good consistency. What's more, patients were divided into low-, moderate-, and high-risk groups according to the scores calculated by the models. The overall survival and disease-specific survival of patients in the high-risk group were significantly worse than those in the moderate- and low-risk group. Conclusions: Our nomogram integrated clinicopathological features and treatment modality to demonstrate excellent performance in risk stratification and prediction of survival outcomes in patients with major salivary gland squamous cell carcinoma after surgery, with important clinical value.

High Rates of Ultraviolet-Signature Mutations in Squamous Cell Carcinomas of the Parotid Gland and Prognostic Implications

In the absence of clear pathologic differences, clinical history may differentiate potential primary parotid squamous cell carcinomas (SCC) from metastases. The presence of an ultraviolet (UV) signature can distinguish between tumors of cutaneous and non-cutaneous origin. This study aimed to investigate rates of UV signature mutations in squamous cell carcinomas of the parotid gland as well as differences in clinical features between tumors of cutaneous and non-cutaneous origin. Clinical and pathologic data were collected from 71 patients with SCC involving the parotid gland, of which 48 had cutaneous, 10 had mucosal, and 13 had no history of SCC. In 34 available cases, genomic DNA was isolated from formalin-fixed paraffin-embedded tissue specimens and sequenced using a targeted hybrid capture 1213 gene panel. Tumor mutational burden and COSMIC (Catalogue of Somatic Mutations in Cancer) mutational signatures were calculated. Most (74%) were UV-positive. Patients with UV-positive tumors were significantly older, white, and had higher rates of sun exposure. Patients with UV-negative tumors had a significantly higher mortality rate and shorter time to death: 6 (67%) died of disease with a median time to death of 9 months compared to 5 (20%) UV-positive patients who died of disease with a median time to death of 32 months. Pathologic features did not significantly vary by clinical history or UV status. The presence of a UV-signature combined with clinical history can be used to determine the primary source of SCC involving the parotid gland. UV-positivity may reflect a less aggressive disease course in an older population.

Cancer Stem Cell Markers in Squamous Cell Carcinomas of the Salivary Glands

BACKGROUND

Cancer stem cells (CSC) are cells that exhibit stem cell properties and are pivotal in tumor biology. CSC markers have been described for many tumorous entities. However, to this date, there is no data on CSC markers in respect to squamous cell carcinomas (SCC) of the salivary glands.

METHODS

Histologic samples from patients with salivary gland SCCs were stained for CSC markers (ALDH-1/BMI-1/SOX-2/CD-44/vimentin) and divided into high and low expression subgroups. These were then correlated with tumor and patient characteristics as well as overall survival (OS), disease-specific survival, recurrence-free survival and local control rates (LCR) after 3 and 5 years.

RESULTS

Overall, 31 samples were included. CD-44 and ALDH-1 expression were associated with tumor origin (metastatic/primary disease, p = 0.048 and p = 0.011, respectively). Strong BMI-1 expression was associated with poorer OS (62.9 vs. 27.3%, p = 0.029), strong SOX-2 expression was associated with poorer LCR (62.5 vs. 21.9%, p = 0.007).

CONCLUSION

CD-44 and ALDH-1 may be useful in differentiating between primary SCCs and metastatic disease. BMI-1 and SOX-2 are correlated with poorer prognosis.

The Role of Postoperative Radiotherapy and Prognostic Model in Primary Squamous Cell Carcinoma of Parotid Gland

Background

Primary squamous cell carcinoma of parotid gland (parotid SCC) is a high malignant histologic subtype of parotid cancers with aggressive clinical presentation. However, the clinical features and survival benefit of postoperative radiotherapy (PORT) for primary parotid SCC are not well known.

Methods

A retrospective population-based study was performed to identify the role of PORT in parotid SCC patients diagnosed between 1975 and 2016 from SEER database. A prognostic risk model was established based on patient clinical features, including age, tumor stage, and node involvement status. Patients were stratified into high, intermediate, and low risk according to this model. The survival benefit of radiotherapy was compared in the whole cohort and different risk groups.

Results

Nine hundred thirty-one parotid SCC patients were extracted from SEER database, 634 (68.1%) in the RT group and 286 (30.7%) in the non-RT group. Overall, 503 (54.0%) deaths occurred, with a median follow-up of 84 months, the 5-year OS was 43.6% in the whole cohort, 47.7 vs 35.9% in patients with/without PORT (P = 0.005), and 58.9 vs. 38.8 vs. 27.1% in low-, intermediate-, and high-risk group (P < 0.001). Compared with surgery alone, PORT significantly improved the OS of patients with medium risk (47.5 vs. 20.6, P < 0.001), whereas not in the low risk (61 vs. 54%, P = 0.710) and high (25.6 vs. 28.7%, P = 0.524).

Conclusion

This prognostic model can separate the patients with parotid squamous cell carcinoma into different risk. PORT significantly improved the OS of patients with intermediate risk, whereas high-risk group may need more intensive treatment strategies.

Primary squamous cell carcinoma of the parotid gland: clinicopathological characteristics, treatment, and prognosis

Squamous cell carcinoma (SCC) of the parotid gland is a rare aggressive malignancy with a poor prognosis. The clinical behaviour, histopathological characteristics, and treatment strategies for parotid SCC still need to be comprehensively demonstrated. In this study, a retrospective review of patients diagnosed with parotid SCC was performed, covering the past two decades. Twenty-nine patients with primary parotid SCC and 10 patients with recurrent parotid SCC were identified. The clinicopathological characteristics of parotid SCC were summarized. Imaging records were used to determine the extent of invasion of the parotid SCC. Histopathological alterations in the parotid resulting from the infiltration of SCC were demonstrated. A set of treatment strategies was developed, involving parotidectomy, neck dissection, facial nerve treatment, defect repair, adjuvant radiotherapy, and chemotherapy/targeted therapy. The median patient survival was 24 months for those with primary parotid SCC and 14.5 months for those with recurrent parotid SCC. Comparatively, patients with a larger tumour size of primary parotid SCC experienced poorer overall survival (hazard ratio 8.986; P=0.013). Great efforts have been made over the past two decades to identify and treat parotid SCC. Consensus regarding therapeutic options for parotid SCC has not been widely achieved and there is still a great need for well-designed prospective studies.

Evaluation of Lateral Temporal Bone Resection in Locally Advanced Tumours of the Parotid Gland

This study evaluated the effects of lateral temporal bone resection (LTBR) on local tumour control in patients with locally advanced parotid gland tumours. The medical records of seven patients treated with radical parotidectomy combined with LTBR for locally advanced primary parotid tumour at the Otolaryngology Department of Dokuz Eylul University between January 1995 and December 2016 were retrospectively evaluated. Demographic variables, tumour characteristics, treatment properties, postoperative complications, follow-up durations and local, regional and distant recurrences were analysed. Before referral to our clinic, four patients had de novo primary parotid tumours, and three patients had a recurrence of primary parotid tumours. The histopathologic diagnoses were squamous cell carcinoma in two patients, and adenosquamous carcinoma, malignant myoepithelial carcinoma, adenocarcinoma, adenoid cystic carcinoma and spindle cell sarcoma in the other patients. During the follow-up period, one patient died due to postoperative pulmonary embolism in the first month, and four patients died due to distant metastasis without local or regional recurrences. LTBR combined with radical parotidectomy in locally advanced primary malignant parotid gland tumours is a feasible surgical technique for local tumour control. However, the most common cause of death in these cases is distant metastases, despite appropriate resection.

Oncologic outcome and potential prognostic factors in primary squamous cell carcinoma of the parotid gland

BACKGROUND

Primary parotid squamous cell carcinoma (SCC) is an uncommon tumour, and there is limited data on its prognosis and treatment. The goal of the current study was to analyse the potential prognostic factors and clinical outcomes for this tumour type.

METHODS

Consecutive patients with surgically treated primary parotid SCC were retrospectively enrolled in this study. The primary end point was locoregional control (LRC) and disease-specific survival (DSS), which were calculated by the Kaplan-Meier method. Independent prognostic factors were evaluated by the Cox proportional hazards method.

RESULTS

In total, 53 patients were included for analysis. Perineural and lymphovascular invasion were observed in 21 and 16 patients, respectively. Intraparotid node (IPN) metastasis was reported in 23 patients with an incidence rate of 43.3%. Twenty-six patients with cN0 disease underwent neck dissection, and pathologic node metastasis was observed in 10 cases. The 5-year LRC and DS S rates were 35 and 49%, respectively. The Cox model was used to report the independence of disease stage and IPN metastasis in predicting LRC and the independence of disease stage and perineural invasion in predicting DSS.

CONCLUSIONS

The prognosis of primary parotid SCC is relatively unfavourable. IPN metastasis significantly decreases disease control, disease stage is the most important prognostic factor, and neck dissection is suggested for patients at any stage.

Understanding primary parotid squamous cell carcinoma - A systematic review

INTRODUCTION

The true incidence of primary parotid squamous cell carcinoma (SCC) is unknown and likely overestimated in the literature. The aim of this systematic review is to examine the diagnosis, aetiology and incidence of parotid SCC by analysing studies evaluating primary parotid SCC.

METHODS

A systematic search of Medline, EMBASE and Cochrane library was performed. A narrative synthesis was done.

RESULTS

A total of 14 observational retrospective studies on primary parotid SCC were included. There are currently no standard criteria for ascertainment of primary parotid SCC. Primary parotid SCC is thought to be due to squamous metaplasia within the ductal epithelium and subsequent invasive squamous carcinoma. Histological features that favour primary disease includes SCC confined to parotid parenchyma with no direct communication to the skin and the absence of mucin. Incidence of primary parotid SCC varied from 1.54 to 2.8 cases per million person-years. Around 30%-86% of patients recorded to have primary parotid SCC on clinical records, when scrutinised, were in fact secondary to parotid lymph node involvement following regional advancement from skin or upper aerodigestive tract SCC.

CONCLUSION

Primary parotid SCC is rare and it is currently a diagnosis of exclusion. Thorough clinical assessment including endoscopy, preoperative imaging and the scrutiny of histopathological findings allow for differentiation between primary and secondary SCC within the parotid. This thus affects both initial treatment and subsequent follow-up.

Chronic atypical first bite syndrome and primary squamous cell carcinoma of the parotid

BACKGROUND

First bite syndrome is a well-recognized complication of parapharyngeal space surgery. There are no reported cases of protracted first bite syndrome and subsequent diagnosis of a primary squamous cell carcinoma (SCC) of the parotid.

METHODS

We present the case of a 73-year-old man with no surgical history and 9 years of first bite syndrome who was ultimately diagnosed with a primary SCC of the parotid. Diagnostic workup, including MRI and biopsy, along with oncologic treatment, were performed.

RESULTS

Surgical treatment confirmed malignancy and also resulted in complete resolution of the first bite syndrome.

CONCLUSION

First bite syndrome without prior surgery may warrant further diagnostic workup with imaging to evaluate for salivary gland pathology. When no radiographic mass lesion is detected but the patient displays protracted symptoms unresponsive to conservative therapy, one should maintain an index of suspicion for malignancy, especially in the presence of symptom escalation.

Comparison of microRNA profiles between benign and malignant salivary gland tumors in tissue, blood and saliva samples: a prospective, case-control study

Introduction

Salivary gland tumors (SGTs) are rare head and neck malignancies consisting of a spectrum of tumors with different biological behaviors.

Objective

In this study we aimed to find out differential expression of microRNA profiles between benign and malignant SGTs.

Methods

We investigated the possible role of 95 microRNAs in the 20 patients with salivary gland tumors with comparison of 17 patients without malignancy or salivary gland diseases. Sixteen of the tumors were benign (seven pleomorphic adenomas, nine Warthin tumors), four of them were malignant (two squamous cell carcinomas, one high grade mucoepidermoid carcinoma, one adenocarcinoma). Serum and saliva samples were collected from both patients and control group. Tissue samples of tumor masses were also collected from patient group.

Results

Among studied microRNAs miR-21, miR-23a, miR-27a, miR-223, miR-125b, miR-126, miR-146a, miR-30e were down regulated in the benign group compared to control group in the serum samples (p-values are 0.04, 0.00005, 0.00005, 0.0022, 0.031, 0.00008, 0.044, and 0.0007, respectively). When tissue samples were studied miR-21, miR-31, miR-199a-5p, miR-146b, miR-345 were up-regulated in the malignant group compared to benign group (p values are 0.006, 0.02, 0.013, 0.013, 0.041, respectively). miR-30e showed statistically significant up-regulation in malignant tumor group's plasma samples compared to benign group (p = 0.034). There was no statistically significant difference in saliva samples between groups.

Conclusion

Our results showed that different microRNAs may play role in salivary tumor pathogenesis according to biological behavior. Although there was no difference in saliva samples between groups, according to tissue and serum samples miR-21 and 30e may have an important role; since they were down-regulated in benign tumors whereas up-regulated in malignant ones.

A proportion of primary squamous cell carcinomas of the parotid gland harbour high-risk human papillomavirus

AIMS

In the current study, we aimed to examine primary parotid squamous cell carcinoma (ParSCC) for the presence of high-risk human papillomavirus (HR-HPV) and associated molecular alterations.

METHODS AND RESULTS

Eight cases of ParSCC were retrieved after a detailed clinicopathological review to exclude the possibility of metastasis and/or extension from another primary site. HR-HPV status was determined on the basis of immunohistochemistry (IHC) for p16 expression and chromogenic in-situ hybridization (CISH) for HR-HPV. All cases were genotyped with a multiplexed mass spectrometry assay interrogating 91 hotspot mutations in eight cancer-related genes (EGFR, KRAS, NRAS, BRAF, PIK3CA, AKT1, MEK1 and ERBB2), and studied by fluorescence in-situ hybridization for PTEN copy number alteration. Three of eight cases (37.5%) were positive for the presence of HR-HPV by CISH and p16 IHC. One of three (33%) HR-HPV-positive cases harboured a PTEN hemizygous deletion, and one (33%) HR-HPV-positive case harboured a PIK3CA E545K somatic mutation. No alteration of the PTEN-PI3K pathway was detected in HR-HPV-negative tumours. Over a median follow-up period of 66.2 months, only the patient with the HR-HPV-positive PIK3CA-mutated tumour died of his disease, the remaining seven patients being disease-free.

CONCLUSIONS

Given the established aetiological role of HR-HPV in other head and neck squamous cell carcinomas, it is likely that HR-HPV represents an oncogenic driver in the pathogenesis of more than one-third of ParSCCs. The presence of HR-HPV in ParSCC may be coupled with alterations in the PTEN-PI3K pathway. Further studies on HR-HPV and the molecular characterization of a larger number of ParSCCs are needed to determine the clinical significance of these findings.

Squamous cell carcinoma of the parotid gland: a population-based analysis of 2545 cases

PURPOSE

Squamous cell carcinoma (SCC) of the parotid gland is an uncommon tumor, which generally affects older patients. In this study, we explore various aspects of this entity using a national population-based database.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) registry was used to extract data on frequency, incidence, and disease-specific survival (DSS) from 1973 to 2009. Variables analyzed included age, gender, race, histologic grade, stage and treatment. Cox proportional hazards analysis was conducted.

RESULTS

A total of 2545 cases were identified. Parotid SCC was most common in males (79.8%), whites (92.9%), and patients aged ≥75 years (51.4%). Incidence increased slightly over the past three decades (annual percent change 1.90%, p<0.05). Overall 5-year DSS was 54.4%. Statistically significant poor prognostic factors included black race, age ≥75 years, tumor T3 or greater, and higher clinical stage at diagnosis. Elective neck dissection (END) in patients staged N0 was associated with higher DSS (78.3% versus 51.1%, p<0.0001). The omission of END was associated with a three-fold greater hazard of death (hazard ratio 3.19, 95% confidence interval 1.53-7.26, p=0.0016), regardless of whether or not radiotherapy was given.

CONCLUSION

Parotid SCC is uncommon, and data on treatment decisions are limited. Our study profiles the demographic, clinicopathologic, incidence, and survival features of this entity. Perhaps most notably, our results support the practice of END of the N0 neck.

Primary squamous cell carcinoma of the parotid gland: a rare entity

Primary squamous cell carcinoma of the parotid gland is a rare aggressive malignancy. It is a rapidly advancing lesion which, if not recognised and treated early, results in high morbidity and mortality. Despite radical surgery and adjuvant radiotherapy, prognosis of this cancer continues to be poor. Careful clinical and histological examination is mandatory to differentiate this tumour from metastatic squamous cell carcinoma and other primary malignancies of the parotid. The authors hereby report the case of a 50-year-old male patient who presented with a progressively increasing, painless mass in parotid region of 6 months duration. An initial fine-needle aspiration cytology and subsequent histopathological examination confirmed that the tumour was squamous cell carcinoma. As no other primary source could be demonstrated in the patient, a final diagnosis of primary squamous cell carcinoma of parotid was offered. Currently the patient is on regular follow-up without any signs of recurrence.

Epidermoid Carcinoma Involving the Parotid Gland and Orbital Region: Case Report of a Rare Entity

Epidermoid carcinoma (also known as squamous cell carcinoma) of the parotid gland is more prevalent among the elderly, as are other head and neck tumors. In most cases it is observed either as a nodal metastasis of a primary tumor that drains into the parotid area or as a direct extension of a tumor that has originated in the upper dermis. Primary epidermoid carcinomas arising directly from the parotid gland are extremely rare. Similarly, secondary invasion of the orbital region by a neighboring tumor is more common than primary epidermoid carcinoma of the orbit, which is also rare. In this article, we discuss the diagnosis and treatment of a rare case of epidermoid carcinoma simultaneously invading the parotid gland and the orbit.