Primary intranodal Warthin-like variant of mucoepidermoid carcinoma

This report describes a rare case of primary intranodal Warthin-like mucoepidermoid carcinoma (WL-MEC) presenting as a left level II lymph node mass in a 48-year-old man. Warthin-like mucoepidermoid carcinoma is a recently defined variant of MEC that bears a close histologic resemblance to Warthin tumor. Whereas MEC has readily identifiable key histologic features that render diagnosis relatively straightforward, WL-MEC is a challenging diagnosis due to overlapping histologic features and only limited case reports in the literature. This case was initially diagnosed as primary intranodal MEC after the exclusion of metastasis by imaging. It was not until years later, upon review of historic cases, that the diagnosis of WL-MEC was established. This diagnosis was further supported by molecular testing that was not available at the time of the original diagnosis.

Macroscopic examination of pathology specimens: a critical reappraisal

Meticulous macroscopic examination of specimens and tissue sampling are crucial for accurate histopathology reporting. However, macroscopy has generally received less attention than microscopy and may be delegated to relatively inexperienced practitioners with limited guidance and supervision. This introductory paper in the minisymposium, Macroscopy Under the Microscope, focuses on issues regarding macroscopic examination and tissue sampling that have been insufficiently addressed in the published literature. It highlights the importance of specimen examination and sampling, discusses some general principles, outlines challenges and suggests potential solutions. It is critical to get macroscopy right the first time as it may not be possible to rectify errors even with expert histological assessment or to retrospectively collect missing data after the specimen retention period. Dissectors must, therefore, receive adequate guidance and supervision until they are proficient in macroscopic specimen examination. We emphasise the importance of the clinical context, optimal specimen fixation, succinct and clinically relevant macroscopic descriptions, macrophotography and judicious tissue sampling. We note that current recommendations based on the number of blocks to be submitted per maximum tumour dimension are ambiguous as the amount of tissue submitted in a cassette is not standardised and it is unclear whether 'block' refers to a tissue block or a paraffin block. Concerns around potential oversampling of 'therapeutic' specimens that could result in overdiagnosis due to detection of incidentalomas are also discussed. We hope that the issues discussed in this paper will engender debate on this clinically critical aspect of pathology practice.

Macroscopy of specimens from the head and neck

Macroscopic examination of surgical resections from the head and neck may be difficult due to the complex anatomy of this area. Recognition of normal anatomical structures is essential for accurate assessment of the extent of a disease process. Communication with the surgical team, correct specimen orientation and sampling are critical for assessment and the importance of radiological and clinical correlation is emphasised. Tumour involvement at each subsite is highlighted with reference to where there are implications on pathological staging and the potential need for adjuvant therapy.

Practice patterns in management of differentiated thyroid cancer since the 2014 British Thyroid Association (BTA) guidelines

BACKGROUND

The updated 2014 BTA guidelines emphasised a more conservative, risk adapted model for the management of low-risk differentiated thyroid cancer (DTC). In comparison to historical approach of total thyroidectomy combined with radioactive iodine, treatment de-escalation is increasingly supported.

AIMS

To evaluate the impact of the updated BTA guidelines on the management of DTC cases at regional UK centre.

METHODS

All DTC patients were retrospectively identified from regional thyroid MDT database between Jan2009-Dec2020. Oncological treatment and clinico-pathological characteristics were analysed.

RESULTS

623 DTC cases were identified; 312 (247 female: 65 male) between 2009 and 2014 and 311 (225 female: 86 male) between 2015 and 2020. Median age is 48 years (range 16-85). By comparing pre- and post-2015 cohorts, there was a significant drop in total thyroidectomy (87.1% vs 76.8%, p = 0.001) and the use of radioactive iodine (RAI) (73.1% vs 62.1%, p = 0.003) in our post-2015 cohort. When histological adverse features were analysed, extra-thyroidal extension (4.2% vs 17.0%, p=< 0.001), lymphovascular invasion (31.4% vs 50.5%, p=<0.001) and multi-centricity (26.9% vs 43.4%, p = 0.001) were significantly increased in the post 2015 cohort. Nonetheless, total thyroidectomy (TT) remains the treatment choice for low risk T1/2 N0 M0 disease in 65.3% (124/190) in post-2015 cohort for several reasons. Reasons include adverse histological features (50.8%), benign indications (32.5%), contralateral nodules (11.7%), patient preference (2.5%), and diagnostic uncertainty (2.5%).

CONCLUSION

Our study confirms a move towards a more conservative approach to patients with low-risk DTC in the UK, which is in keeping with the BTA 2014 guideline and international trends, but total thyroidectomy remains prevalent for low risk T1/2 N0 M0 disease for other reasons.

Developing and Validating a Multivariable Prognostic-Predictive Classifier for Treatment Escalation of Oropharyngeal Squamous Cell Carcinoma: The PREDICTR-OPC Study

PURPOSE

While there are several prognostic classifiers, to date, there are no validated predictive models that inform treatment selection for oropharyngeal squamous cell carcinoma (OPSCC).Our aim was to develop clinical and/or biomarker predictive models for patient outcome and treatment escalation for OPSCC.

EXPERIMENTAL DESIGN

We retrospectively collated clinical data and samples from a consecutive cohort of OPSCC cases treated with curative intent at ten secondary care centers in United Kingdom and Poland between 1999 and 2012. We constructed tissue microarrays, which were stained and scored for 10 biomarkers. We then undertook multivariable regression of eight clinical parameters and 10 biomarkers on a development cohort of 600 patients. Models were validated on an independent, retrospectively collected, 385-patient cohort.

RESULTS

A total of 985 subjects (median follow-up 5.03 years, range: 4.73-5.21 years) were included. The final biomarker classifier, comprising p16 and survivin immunohistochemistry, high-risk human papillomavirus (HPV) DNA in situ hybridization, and tumor-infiltrating lymphocytes, predicted benefit from combined surgery + adjuvant chemo/radiotherapy over primary chemoradiotherapy in the high-risk group [3-year overall survival (OS) 63.1% vs. 41.1%, respectively, HR = 0.32; 95% confidence interval (CI), 0.16-0.65; P = 0.002], but not in the low-risk group (HR = 0.4; 95% CI, 0.14-1.24; P = 0.114). On further adjustment by propensity scores, the adjusted HR in the high-risk group was 0.34, 95% CI = 0.17-0.67, P = 0.002, and in the low-risk group HR was 0.5, 95% CI = 0.1-2.38, P = 0.384. The concordance index was 0.73.

CONCLUSIONS

We have developed a prognostic classifier, which also appears to demonstrate moderate predictive ability. External validation in a prospective setting is now underway to confirm this and prepare for clinical adoption.

A quantitative assessment of the number of disease foci in papillary thyroid cancer

AIM

Multifocality is a frequent feature of papillary thyroid carcinoma (PTC). Its prognostic value is controversial although national guidelines recommend treatment intensification if present. However, multifocality is not a binary but discrete variable. This study aimed to examine the association between increasing number of foci and risk of recurrence following treatment.

METHODS

577 patients with PTC were identified with median follow-up of 61 months. Number of foci were taken from pathology reports. Log-rank test was used to assess significance. Multivariate analysis was performed and Hazard Ratios were calculated.

RESULTS

Of 577 patients, 206(35%) had multifocal disease and 36(6%) recurred. 133(23%), 89(15%) and 61(11%) had 3+, 4+ or 5+ foci respectively. The 5-year RFS stratified by number of foci was 95%v93% for 2+foci (p = 0.616), 95%v96% for 3+foci (p = 0.198) and 89%v96% for 4+foci (p = 0.022). The presence of 4 foci was associated with an over 2-fold risk of recurrence (HR 2.296, 95% CI 1.106-4.765, p = 0.026) although this was not independent of TNM staging. Of the 206 multifocal patients, 31(5%) had 4+foci as their sole risk factor for treatment intensification.

CONCLUSION

Although multifocality per se does not confer worse outcome in PTC, finding 4+foci is associated with worse outcome and could therefore be appropriate as a cut-off for treatment intensification. In our cohort, 5% of patients had 4+foci as a sole indication for treatment intensification, suggesting that such a cut off could impact clinical management.

The role of liquid biopsy in management of the neck with indeterminate response on post-treatment imaging following non-surgical management of oropharyngeal cancer

INTRODUCTION

This study aimed to determine if post-treatment HPV cell-free DNA (cfDNA) can assist in the decision-making process for salvage neck dissection in patients following non-surgical treatment of oropharyngeal squamous cell carcinoma (OPSCC) with a partial response in the neck on imaging at 12 weeks post-treatment.

METHODS

86 patients who completed treatment were prospectively recruited through the regional multidisciplinary team (MDT). Treatment response was categorised as complete response (CR), partial response (PR) or progressive disease on 12-week post-treatment imaging. Pre- and post-treatment blood samples were assessed for HPV cfDNA through droplet digital PCR (ddPCR).

RESULTS

Eight patients had an isolated partial response in the neck. One (12.5%) had detectable HPV cfDNA (22.96 copies/ml) at ∼12 weeks post-treatment with positive disease on subsequent neck dissection (positive predictive value; PPV = 100%). Of the seven patients with undetectable HPV cfDNA, two patients had evidence of regional disease recurrence at 23.9 and 27.4 months respectively (negative predictive value; NPV = 71%).

CONCLUSION

The detection of HPV cfDNA may help target salvage therapy in patients with a partial response in the neck. Follow-up studies in larger cohorts would be required to further validate the use of post-treatment HPV cfDNA in the management of OPSCC.

Histology segmentation using active learning on regions of interest in oral cavity squamous cell carcinoma

In digital pathology, deep learning has been shown to have a wide range of applications, from cancer grading to segmenting structures like glomeruli. One of the main hurdles for digital pathology to be truly effective is the size of the dataset needed for generalization to address the spectrum of possible morphologies. Small datasets limit classifiers' ability to generalize. Yet, when we move to larger datasets of whole slide images (WSIs) of tissue, these datasets may cause network bottlenecks as each WSI at its original magnification can be upwards of 100 000 by 100 000 pixels, and over a gigabyte in file size. Compounding this problem, high quality pathologist annotations are difficult to obtain, as the volume of necessary annotations to create a classifier that can generalize would be extremely costly in terms of pathologist-hours. In this work, we use Active Learning (AL), a process for iterative interactive training, to create a modified U-net classifier on the region of interest (ROI) scale. We then compare this to Random Learning (RL), where images for addition to the dataset for retraining are randomly selected. Our hypothesis is that AL shows benefits for generating segmentation results versus randomly selecting images to annotate. We show that after 3 iterations, that AL, with an average Dice coefficient of 0.461, outperforms RL, with an average Dice Coefficient of 0.375, by 0.086.

Abstract 3408: Longitudinal measurement of HPV copy number in cell free DNA predicts progression free survival in HPV positive oropharyngeal cancer

Oropharyngeal squamous cell carcinoma (OPSCC) is increasing in global prevalence and is divided into two types dependent on association with human papillomavirus (HPV), with a more favorable prognosis in HPV+ve tumors. Assay of HPV copy number in plasma cell-free DNA (cfDNA) provides a minimally invasive method for detecting and monitoring tumor-derived HPV, with potential for enhancing clinical care. We have evaluated the utility of cfDNA droplet digital PCR (ddPCR) as a method for characterisation and longitudinal monitoring of patients with OPSCC in a prospectively recruited cohort of 104 OPSCC patients. ddPCR assay of cfDNA for five HPV types showed overall 95% concordance with p16 immunohistochemistry (IHC) and PCR analysis of solid tumor tissue. Longitudinal sampling in 48 HPV+ve patients, with median follow-up of 20 months, strongly predicted patient outcomes. Progression-free survival, stratified respectively by the presence or absence of detectable HPV cfDNA at a median of 13 weeks post-treatment, was 50% and 88% (p=0.001, hazard ratio 10.0 (95% CI 2.1-47.1)). In two patients, greater reliance on sequential HPV measurement would have avoided surgical intervention which ultimately did not confirm disease recurrence. The high concordance of pre-treatment plasma cfDNA-HPV analysis with p16 IHC and HPV-PCR of solid tissue, together with the predictive value and utility of sequentially measured post-treatment cfDNA-HPV copy number, provide a compelling case for the routine use of cfDNA-HPV ddPCR in management of OPSCC and for clinical trials to assess its impact on treatment outcomes.

Citation Format: Martyna Joanna Adamowicz, Sophie J. Warlow, John P. Thomson, Lara M. Carey, Helen Thain, Robert Wescott, Kate Cuschieri, Lucy Q. Li, Brendan Conn, Ashley Hay, Iain J. Nixon, Timothy J. Aitman. Longitudinal measurement of HPV copy number in cell free DNA predicts progression free survival in HPV positive oropharyngeal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3408.

Longitudinal measurement of HPV copy number in cell-free DNA is associated with patient outcomes in HPV-positive oropharyngeal cancer

INTRODUCTION

Oropharyngeal squamous cell carcinoma (OPSCC) is increasing in global prevalence and is divided into two types dependent on association with human papillomavirus (HPV). Assay of HPV copy number in plasma cell-free DNA (cfDNA) provides a minimally invasive method for detecting and monitoring tumour-derived HPV, with potential for enhancing clinical care.

MATERIALS AND METHODS

In a prospectively recruited cohort of 104 OPSCC patients, we evaluate the utility of cfDNA droplet digital PCR (ddPCR) as a method for characterisation and longitudinal monitoring of patients with OPSCC.

RESULTS

ddPCR assay of pre-treatment plasma cfDNA for five HPV types showed overall 95% concordance with p16 immunohistochemistry and PCR analysis of tumour tissue. Longitudinal sampling in 48 HPV+ve patients, with median follow-up of 20 months, was strongly associated with patient outcomes. Persistently elevated cfDNA-HPV post-treatment was associated with treatment failure (2/2 patients) and an increase of cfDNA-HPV in patients whose HPV levels were initially undetectable post-treatment was associated with disease recurrence (5/6 patients). No recurrence was observed in patients in whom cfDNA-HPV was undetectable in all post-treatment samples. In two patients, sequential HPV measurement could have avoided surgical intervention which did not confirm recurrence.

CONCLUSION

The high concordance of pre-treatment plasma cfDNA-HPV analysis with tissue-based assays, together with the clinical associations of sequentially measured post-treatment cfDNA-HPV copy number add to a growing body of evidence that suggest utility of cfDNA-HPV ddPCR in management of OPSCC. Standardised clinical trials based on these data are now needed to assess the impact of such testing on overall patient outcomes.

Evaluation of Histopathological Risk Model in a Cohort of Oral Squamous Cell Carcinoma Patients Treated with Accompanying Neck Dissection

To investigate the applicability of the validated histological risk model in a cohort of oral cavity squamous cell carcinoma patients treated concurrently with neck dissections. Primary tumours from 85 patients with primary excision of T1 and T2 Oral Squamous Cell Carcinomas (TNM 7th edition) including neck dissection were scored by three pathologists in consensus according to the validated risk model. The risk score data, along with traditional dataset values, were analysed to determine possible association with nodal metastasis and extracapsular spread. Seventy-two patients (54%) were classified with low or intermediate risk and 62 (46%) patients were 'high risk'. A chi squared test showed that cases with nodal metastasis were highly statistically significant with the overall risk model score (X² = 22.62 p = 0.0001). None of the neck dissections from tumours with low risk score showed evidence of metastasis (NPV = 100%) suggesting the risk score may also be a useful tool for predicting an absence of metastasis. Risk assessment of low-stage oral squamous cell carcinoma primary tumours may be predictive of the presence or absence of metastasis at presentation. Knowledge of the risk score and its constituent parts may inform treatment decisions at multidisciplinary meetings. Low risk squamous cell carcinoma may be a rare variant with low metastatic potential and excellent long-term survival.

Evaluating the predicted impact of changes to the AJCC/TMN staging system for differentiated thyroid cancer (DTC): A prospective observational study of patients in South East Scotland

OBJECTIVES

To assess the impact of the eighth edition AJCC/TMN staging system on patients with new diagnoses of differentiated thyroid cancers presenting to our regional multidisciplinary team meetings.

DESIGN

We analysed Endocrine Cancer MDT meeting records from 2009 to 2015 to identify all patients in the region presenting with a new diagnosis of differentiated thyroid cancer. We re-staged patients according to the eighth edition AJCC/TNM staging classification and analysed the survival outcomes of patients in each stage under the seventh and eighth systems.

SETTING

Tertiary referral centre in South East Scotland (NHS Lothian).

PARTICIPANTS

Three hundred and sixty-one patients were newly diagnosed with DTC within South East Scotland during the study period and met our inclusion criteria.

MAIN OUTCOME MEASURES

Disease-specific mortality at any time during follow-up.

RESULTS

In total, 119 of 361 (33%) patients were re-staged when the eighth edition AJCC/TMN system was applied. The number of patients classified as having advanced stage (III/IV) disease fell from 76 (21%) to 8 (2%). The most common reason for down-staging was re-classification of tumour size, a factor in 96 (80.7%) down-staged patients. The five-year disease-specific survival of the cohort overall was 98%. Overall, 7 (1.9%) thyroid cancer-related deaths occurred during follow-up, three of whom were down-staged.

CONCLUSIONS

On implementation of the eighth edition of the AJCC/TMN staging system, we expect many patients who would previously have been considered to have advanced thyroid cancer will now be classified as early stage. This will accurately reflect their excellent survival outcomes.

Bilateral submandibular gland nodular oncocytic hyperplasia with papillary cystadenoma-like areas

A 57-year-old man presented in 2016 with a 4-month history of a right submandibular mass, having undergone left submandibular gland (SMG) excision in 2003. Imaging suggested a benign tumour and subsequent core biopsy findings suggested a nodular oncocytic hyperplasia, similar to the tumour removed from the contralateral side. This was confirmed on histological analysis following right submandibular gland excision which showed characteristic features of nodular oncocytic hyperplasia along with an unusual diffuse papillary cystadenoma-like ductal proliferation, similar to that seen in the 2003 specimen. A diagnosis of multinodular adenomatous oncocytic hyperplasia (MAOH) was rendered in order to communicate the unique histological features that have otherwise not been described in the literature. We believe that this is the first reported case of non-synchronous multinodular oncocytic hyperplasia and the first case affecting the submandibular glands.

Metastasising Pleomorphic Salivary Adenoma: A Rare Case Report of a Massive Untreated Minor Salivary Gland Pleomorphic Adenoma with Concurrent Ipsilateral Cervical Node Metastases

Salivary gland tumours constitute approximately 1-5% of all human neoplasms. Pleomorphic adenoma (PA) is the commonest benign neoplasm affecting the parotid gland most often (> 75%), followed by the submandibular gland (13%), then the palate (9%). Metastasising pleomorphic adenoma (MPA) is extremely rare. The effects can be severe and a reported 40% of MPA patients die with disease. This case represents the first known case in English literature of an untreated minor salivary gland PSA of the palate metastasising to an ipsilateral cervical node. We report a 61 year old female who presented with a large tumour occupying the palatal vault, and cervical neck mass. The oral tumour was believed to have been growing over four decades. The patient died eight months following surgical resection. Of known cases, male: female ratio is 35:51 and the mean age at diagnosis is 49.2. Most commonly, MPA is detected in bone 33.3% (n = 29), lung 31% (n = 27) and cervical lymph nodes 20.7% (n = 18). Thorough reporting is deemed essential to further understand the biological differences of non metastasising and metastasising PAs, treatment outcomes, prognosis and survival rates.

Decompression of keratocystic odontogenic tumors leading to increased fibrosis, but without any change in epithelial proliferation

OBJECTIVE

The aim of this study was to investigate whether decompression treatment induces changes in the histology or biologic behavior of keratocystic odontogenic tumor (KCOT).

STUDY DESIGN

Seventeen patients with KCOT underwent decompression treatment with or without enucleation. Histologic evaluation and immunohistochemical expression of p53, Ki-67, and Bcl-2 were analyzed by using conventional microscopy.

RESULTS

KCOT showed significantly increased fibrosis (P = .01) and a subjective reduction in mitotic activity (P = .03) after decompression. There were no statistically significant changes in the expression of proliferation markers. An increase in daughter-cysts or epithelial rests was seen after decompression (P = .04). Recurrence was noted in four of 16 cases, and expression of p53 was strongly correlated with prolonged duration of treatment (P = .01) and intense inflammatory changes (P = .02).

CONCLUSIONS

Structural changes in the KCOT epithelium or capsule following decompression facilitate surgical removal of the tumor. There was no statistical evidence that decompression influences expression of proliferation markers in the lining, indicating that the potential for recurrence may not be restricted to the cellular level. The statistically significant increase of p53 expression with increased duration of treatment and increase of inflammation may also indicate the possibility of higher rates of recurrence with prolonged treatment and significant inflammatory changes.

Population-based p16 and HPV positivity rates in oropharyngeal cancer in Southeast Scotland

We assessed a population-based cohort of patients diagnosed with oropharyngeal squamous cell carcinoma in Southeast Scotland over 13 months. p16 and human papilloma virus (HPV) expression were determined, and correlated with stage, treatment, smoking and alcohol history, and disease outcomes. Retrospective analysis was performed on 60 patients. p16 immunohistochemistry and HPV genotyping were performed on formalin-fixed paraffin-embedded tissues. HPV infection (as defined by p16 positivity and/or HPV PCR positivity) was identified in 57% of samples, while dual positives were detected in 45% of cases. HPV16 was most prevalent of the HPV types and was associated with 90% of positive samples. Cause-specific 1-year and 2-year survivals were 82.5% and 78.2%, respectively. The p16-positive and HPV-positive groups demonstrated significantly increased cause-specific survival in comparison with their negative counterparts.

Necrotising sialometaplasia in the floor of mouth

INTRODUCTION

Necrotising sialometaplasia is a benign self-limiting inflammatory process which occurs in the salivary gland tissue. The condition is a diagnostic challenge mimicking malignancy both clinically and histopathologically. Commonly, it presents in the hard palate.

CASE REPORT

Here, we report an unusual case in a 56-year-old man which presented in the floor of the mouth.

Uncommon presentation of nasopharyngeal extramedullary plasmacytoma: a case report and literature review

OBJECTIVE

We report an exceptional presentation of extramedullary plasmacytoma of the nasopharynx without bone marrow involvement or other characteristics of multiple myeloma.

METHOD

Case report and a review of the world literature concerning the clinical presentation, histopathological features, optimal treatment and prognosis of nasopharyngeal extramedullary plasmacytoma.

RESULTS

Reports of patients with symptomatic extramedullary plasmacytomas of the nasopharynx eventually being documented with histopathological evidence are not uncommon; however, the converse appears to be an extremely rare event. The patient was completely asymptomatic and following a paroxysm of coughing, expectorated a polypoidal nodule, which on histopathological investigation had features suggestive of extramedullary plasmacytoma.

CONCLUSION

Although these tumours commonly present with significant nasal symptoms, this exceptional presentation in an asymptomatic patient has never been previously reported. Unusual presentations of rare tumours can pose considerable diagnostic dilemmas to both the surgeon and histopathologist. Awareness of these rarities is important to ensure the best patient care.

In vitro examination of suspicious oral lesions using optical coherence tomography

We compared findings of optical coherence tomography (OCT) with histopathological results of suspicious oral lesions to assess the feasibility of using OCT to identify malignant tissue. Thirty-four oral lesions from 27 patients had swept-source frequency-domain OCT. Four variables were assessed (changes in keratin, epithelial, and sub-epithelial layers, and identification of the basement membrane) and from this we calculated whether or not there were architectural changes. These data were then compared with histopathological results. Two clinicians, who were unaware of the clinical and histopathological diagnoses, decided whether biopsy was necessary. The basement membrane was recognised in only 15 oral lesions. OCT could identify diseased areas but could not provide a diagnosis or differentiate between lesions. The two clinicians, who recommended biopsy agreed in all cases. This pilot study confirms the feasibility of using OCT to identify architectural changes in malignant tissues.