The Natural History and Treatment Outcomes of Perineural Spread of Malignancy within the Head and Neck

Clinical outcomes in perineural spread of cutaneous squamous cell carcinoma via the ophthalmic nerve

BACKGROUND

There are no large studies reporting oncological or survival outcomes for patients diagnosed with perineural spread (PNS) of cutaneous squamous cell carcinoma (cSCC) via the ophthalmic nerve (V1). Where orbital exenteration may be necessary for curative treatment, it is critical to have survival data with which the morbidity associated with surgical treatment can be justified. Furthermore, with the emerging treatment option of immunotherapy, current standard of care outcomes are needed to help guide future trial design and eventually changed management guidelines.

OBJECTIVE

To determine the oncological and survival outcomes observed in patients with PNS of cSCC via V1.

MATERIALS AND METHODS

Retrospective analysis of prospectively maintained cohort of patients with PNS of cSCC via V1 treated in a tertiary Australian head and neck oncology/skull base referral center. Consecutive sample of 53 patients managed between March 1, 1999 and April 30, 2020. Follow-up closure date was September 1, 2021. Curative-intent surgery, curative-intent radiotherapy, or palliative care was undertaken. Endpoints included five-year overall, disease-specific, and disease-free survival from the date of treatment.

RESULTS

Five-year Kaplan-Meier overall survival was 61.9% (95% CI 46.2%-74.3%), with disease-specific survival of 74.6% (95% CI 58.8%-85.3%), and disease-free survival 62.1% (95% CI 46.5%-74.3%). Survival was superior in patients treated via surgery and adjuvant radiotherapy than in those receiving surgery alone or definitive radiotherapy. Survival was superior among patients with less advanced disease as assessed by the Williams zonal staging system; patients with Zone 1 disease had disease-specific survival of 94.1% at 5 years with 82.5% disease-free survival.

DISCUSSION

Five-year oncological and survival outcomes in this cohort were favorable. Superior survival was observed in patients treated with curative-intent surgery and adjuvant radiotherapy. Less extensive disease as delineated by the Williams zonal staging system was associated with improved survival.

CONCLUSION

Surgical resection with adjuvant radiotherapy confers favourable oncological and survival outcome in patients with V1 PNS, particularly with early disease limited to Zone 1.

Assessment of perineural spread in advanced cutaneous squamous cell carcinomas treated with immunotherapy

BACKGROUND

Cutaneous squamous cell carcinoma (CSCC) has a propensity for perineural spread (PNS) which is associated with poorer treatment outcomes. Immunotherapy is the new standard of care treatment for advanced CSCC resulting in durable responses. PNS is not captured by traditional response assessment criteria used in clinical trials, e.g. RECIST 1.1, and there is limited literature documenting radiological PNS responses to immunotherapy. In this study we assess PNS responses to immunotherapy using a modified grading system.

METHODS

This is an Australian single-center retrospective review of patients with advanced CSCC who were treated with immunotherapy between April 2018 and February 2022 who had evidence of PNS on pre-treatment magnetic-resonance imaging (MRI). The primary outcome was blinded overall radiological response in PNS using graded radiological criteria, post-commencement of immunotherapy. Three defined timepoints (< 5 months, 5-10 months, > 10 months) were reviewed. Secondary outcomes included a correlation between RECIST 1.1 and PNS assessments and the assessment of PNS on fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT).

RESULTS

Twenty CSCC patients treated with immunotherapy were identified. Median age was 75.7 years and 75% (n = 15) were male. All patients had locoregionally advanced disease and no distant metastases. Median follow-up was 18.5 months (range: 2-59). 70% (n = 14) demonstrated a PNS response by 5 months. Three patients experienced pseudoprogression. One patient had PNS progression by the end of study follow up. RECIST 1.1 and PNS responses were largely concordant at > 10 months (Cohen's Kappa 0.62). 5/14 cases had features suspicious for PNS on FDG-PET/CT.

CONCLUSIONS

PNS response to immunotherapy can be documented on MRI using graded radiological criteria. High response rates were seen in PNS with the use of immunotherapy in this cohort and these responses were largely concordant with RECIST 1.1 assessments. FDG-PET/CT demonstrated limited sensitivity in the detection of PNS.

Evaluation of facial nerve perineural spread from cutaneous squamous cell carcinoma using 3T MR neurography

INTRODUCTION

Perineural spread (PNS) is a rare but potentially fatal consequence of cutaneous squamous cell carcinoma (cSCC) of the head and neck. We aimed to evaluate the accuracy of 3T MR neurography in detecting and defining the extent of facial nerve (VII) PNS from cSCC, and highlight characteristic radiological features in peripheral branches to improve early diagnosis.

METHODS

Single-institution retrospective review of 38 patients with clinical, radiological, and/or histopathological findings consistent with VII PNS from cSCC who underwent pre-operative 3T MR neurography.

RESULTS

Compared to histopathology (gold standard), 3T MR neurography had a sensitivity of 89% and positive predictive value of 97%. In true-positive cases (n = 33), zonal extent was correctly identified in 100%. Seventy-nine% had simultaneous trigeminal nerve (V) PNS, mostly involving the auriculotemporal branch of the mandibular nerve (64%). When the causative lesion was absent (n = 23), the extra-temporal VII demonstrated asymmetrical enhancement alone (n = 6), bulky expansion (n = 8), or extra-neural spread (n = 9). Peripheral VII branch involvement, particularly the buccal and zygomatic, was readily identified using known anatomical landmarks.

CONCLUSION

3T MR neurography is highly accurate in evaluating VII PNS from cSCC, and thus should be specifically requested by physicians if suspicious for disease. Coexistent V PNS was common, highlighting the need to examine V branches to allow complete treatment planning. The unique radiological patterns identified showcases disease progression. As early detection improves patient outcomes, the radiologist must look for peripheral VII involvement in specific anatomical areas, which is within the capabilities of 3T MR neurography.

Persisting facial nerve palsy or trigeminal neuralgia - red flags for perineural spread of head and neck cutaneous squamous cell carcinoma (HNcSCC)

BACKGROUND

Perineural spread (PNS) of head and neck cutaneous squamous cell carcinoma (HNcSCC) is a unique diagnostic challenge, presenting with insidious trigeminal (CN V) or facial nerve (CN VII) neuropathies without clinically discernible primary masses. These patients are often sub-optimally investigated and misdiagnosed as Bell's palsy or trigeminal neuralgia. This case series highlights the red flags in history and pitfalls that lead to delays to diagnosis and treatment.

METHODS

A retrospective case series of 19 consecutive patients with complete clinical histories with HNcSCC PNS without an obvious cutaneous primary lesion at time of presentation to a quaternary head and neck centre in Australia were identified and included for analysis.

RESULTS

Fifteen had CN VII PNS, 17 had CN V PNS, and 13 had both. The overall median symptom-to-diagnosis time was 12-months (IQR-15 months). Eight patients had CN VII PNS and described progressive segmental facial nerve palsy with a median symptom-to-diagnosis time of 9-months (IQR-11.75 months). Eleven patients had primary CN V PNS and described well localized parathesia, formication or neuralgia with a median symptom-to-diagnosis time of 19-months (IQR 27.5 months).

CONCLUSION

PNS is often mistaken for benign cranial nerve dysfunction with delays in diagnosis worsening prognosis. Red flags such as progressive CN VII palsy or persistent CN V paraesthesia, numbness, formication or pain, particularly in the presence of immuno-compromise and/or a history of facial actinopathy should raise suspicion for PNS. Gadolinium-enhanced MR Neurography should be obtained expediently in patients with persistent/progressive CN V/CN VII palsies in patients with red flags, with low threshold for referral to a Head and Neck Surgeon.

Development of an in vivo murine model of perineural invasion and spread of cutaneous squamous cell carcinoma of the head and neck

Introduction

Cutaneous squamous cell carcinoma of the head and neck (cSCCHN) can metastasize by invading nerves and spread toward the central nervous system. This metastatic process is called perineural invasion (PNI) and spread (PNS). An in vivo sciatic nerve mouse model is used for cSCCHN PNI/PNS. Here we describe a complementary whisker pad model which allows for molecular studies investigating drivers of PNI/PNS in the head and neck environment.

Methods

A431 cells were injected into the whisker pads of BALB/c Foxn1nu and NSG-A2 mice. Tumor progression was monitored by bioluminescence imaging and primary tumor resection was performed. PNI was detected by H&E and IHC. Tumor growth and PNI were assessed with inducible ablation of LOXL2.

Results

The rate of PNI development in mice was 10%-28.6%. Tumors exhibited PNI/PNS reminiscent of the morphology seen in the human disease. Our model's utility was demonstrated with inducible ablation of LOXL2 reducing primary tumor growth and PNI.

Discussion

This model consists in a feasible way to test molecular characteristics and potential therapies, offers to close a gap in the described in vivo methods for PNI/PNS of cSCCHN and has uses in concert with the established sciatic nerve model.

Perineural invasion and perineural spread in periocular squamous cell carcinoma

Perineural invasion (PNI) in cutaneous squamous cell carcinoma (SCC) of the periocular region is a prognostic marker of adverse tumour outcomes. PNI carries a well-established risk of tumour recurrence, regional metastasis and higher likelihood of mortality. This review will explore and stratify the risks conferred by histological PNI parameters. The radiological features of perineural spread (PNS) and the imaging sequences that delineate these findings will also be highlighted. Surgical excision with en face margin control is the preferred technique for achieving histological clearance. Adjuvant radiotherapy improves treatment outcomes in the setting of concomitant high-risk features. For locally advanced or metastatic cutaneous SCC, immunotherapy represents a novel treatment alternative. This review will provide an algorithm for the diagnosis and management of periocular SCC with PNI and PNS.

Patterns and predictors of site-specific recurrence in cervical cancer after radical hysterectomy

AIM

This study examines patterns and predictors of site-specific recurrence to explore the causes of local recurrence of cervical cancer.

METHODS

Radical hysterectomy was performed in 121 patients (stage IB-IIB). Nerve-sparing was performed whenever possible. The first recurrence in local, regional, and distant areas was examined. We investigated the possibility of nerve involvement in local recurrence, focusing on paravaginal tissues containing the pelvic plexus. We provide Supporting Information on local recurrence in the paravaginal area.

RESULTS

Local recurrence was an independent event from regional or distant recurrence. Local recurrence was seen only in high-risk patients, while regional and distant recurrences were not or less related to the risk category. The independent risk factors by logistic regression for local, regional, and distant recurrence were parametrial invasion, vaginal invasion, and lymph node metastasis, respectively. Local recurrence showed a comparable or more significant negative impact on survival than distant recurrence. Among seven patients with local recurrences, five had a recurrence in the paravagina. The rate of paravaginal recurrence was one in 76 early-stage and four in 45 locally advanced diseases. Four sites of paravaginal recurrence occurred on the nerve-sparing side and two on the non-nerve-sparing side. Supporting Information demonstrated histological evidence of perineural spread into the pelvic plexus and perineural invasion of the primary tumor.

CONCLUSIONS

A high percentage of local recurrences are in paravaginal tissue containing the pelvic plexus. The causal association of nerve-sparing surgery and perineural invasion with local recurrence needs to be investigated in large prospective studies.

Survival outcomes of perineural spread in head and neck cutaneous squamous cell carcinoma

AIM

To present an institution's experience and survival outcomes for patients with head and neck cutaneous squamous cell carcinoma (HNcSCC) and perineural spread (PNS).

METHOD

Retrospective study of patients with HNcSCC and PNS treated between January 2010 and August 2020 from the Sydney Head and Neck Cancer Institute database, Sydney, Australia; a high-volume, tertiary, academic head and neck centre. Patient demographics, primary site, involved cranial nerves, treatment modality, loco-regional failure and survival data were obtained.

RESULTS

Forty-five patients were identified, of which 32 patients were male (71%). Mean age at diagnosis was 68.7 years (range 43-90). Median follow-up was 16.1 months (range 1-107). The trigeminal nerve was most frequently involved (n = 30, 66.6%) followed by facial nerve (n = 13, 28.9%). Most patients underwent surgery followed by radiotherapy (n = 33, 73%) and eight received definitive radiotherapy. The median overall survival (OS) was 4.5 years (95% CI 3.71-5.38), median disease-specific survival 5.1 years (95% CI 4.21-5.97) and median disease-free survival (DFS) was 1.7 years (95% CI 1.11-2.22). The estimated 5-year OS and DFS were 45% and 25%, respectively. Patients treated with surgery and adjuvant radiotherapy with a clear proximal nerve margin had favourable DFS (P = 0.035) and trended towards better OS (P = 0.134) compared with patients with an involved nerve margin. Patients treated surgically with involved proximal nerve margins had similar outcomes compared with patients with treated definitive radiotherapy (HR 0.80, 95% CI 0.29-2.22, P = 0.664).

CONCLUSION

The likelihood of achieving a clear proximal nerve margin should be a strong consideration in the selection of appropriate patients for primary surgery.

Neurotropic Cutaneous Malignancies: Case Report on Keratinocyte Derived Malignancies of the Head and Neck With Perineural Invasion

Background

The recent addition of immunotherapy as a treatment modality to surgery and radiation has vastly improved disease control for patients with keratinocyte-derived carcinomas (KCs) that are incurable with local therapies alone. With the advent of immune checkpoint inhibitors (ICPis) in non-melanoma skin cancers comes diagnostic and therapeutic challenges when considering treatment strategies for patients presenting with clinical perineural invasion (cPNI) of locally advanced KC of the head and neck.

Objectives

We report four cases that convey the diagnostic and therapeutic complexity of managing patients with neuropathic symptoms from cutaneous neurotropic carcinomas of the head and neck. We also discuss an updated review regarding immunotherapies and perineural invasion within KC management.

Conclusion

Patients presenting with symptoms suspicious for cPNI warrant an expanded diagnostic evaluation to correlate neurological findings with neurotropic spread of disease. While nerve biopsies can be precarious in sensitive areas, a history of skin cancer and clinical presentation suggestive of neurotropism may be enough to pursue timely management in the form of surgery, radiation, and/or systemic therapy given each patient’s individual priorities, comorbidities, and prognosis. When adding ICPi as a treatment modality for patients with disease not amenable to local therapies, the potential for immune-related adverse events must be considered. A multi-disciplinary review and approach to the management of patients with KC and cPNI is essential for obtaining optimal patient outcomes.

Facial nerve perineural spread from cutaneous squamous cell carcinoma of the head and neck: A single institution analysis of epidemiology, treatment, survival outcomes, and prognostic factors

BACKGROUND

This study aimed to examine patients with facial nerve (VII) perineural spread (PNS) from cutaneous squamous cell carcinoma of the head and neck.

METHODS

Retrospective analysis of patients managed by an Australian tertiary center between 2000 and 2019.

RESULTS

Seventy three patients were included. Most presented with recurrent disease (89.0%) and simultaneous trigeminal nerve (V) involvement (67.1%). Of the 55 patients (75.3%) who received curative intent treatment, 48 received surgery plus/minus post-operative radiotherapy. In these patients, 5-year disease-free survival, disease-specific survival, and overall survival was 50.7%, 68.7%, and 58.1%, respectively. Pathological nodal disease, involved margins, increasing VII zonal extent, and concurrent zone 2 V PNS significantly worsened outcomes.

CONCLUSION

High rates of recurrent disease reflects the importance of adequate treatment of the primary. Surgery and post-operative radiotherapy remains the mainstay treatment. Outcomes are improved in early-stage disease and with clear surgical margins, reinforcing the need for prompt diagnosis and intervention.

Immunotherapy for the treatment of perineural spread in cutaneous head and neck squamous cell carcinoma: Time to rethink treatment paradigms

BACKGROUND

Immune checkpoint inhibitors have shown promising antitumour activity. Application in head and neck cutaneous squamous cell carcinoma (cSCC) large nerve perineural spread (PNS) is limited.

METHODS

Retrospective review of 13 patients with PNS receiving anti-PD-1 therapy from September 2017 to May 2021 is presented. Primary endpoints were objective response (complete or partial response) and median time to progression, determined by Head and Neck Multi-Disciplinary Team (MDT) and independent radiology review of magnetic resonance imaging (MRI) and/or computed tomography/positron emission tomography (CT/PET).

RESULTS

Objective response was observed in 9/13 patients (69%), with complete response in 6 (46%) and partial response in 3 patients (23%). Median time to response was 2.1 months (IQR 1.8-2.7 months). There were 3 (23%) patients with progressive disease, with median time to progression of 3.5 months. There were no grade 3-4 treatment related adverse events.

CONCLUSIONS

This case series supports developing evidence for anti-PD-1 checkpoint inhibitor therapy for perineural spread, supporting future prospective clinical trials in this patient population.

Redefining Perineural Invasion in Head and Neck Cutaneous Squamous Cell Carcinoma

OBJECTIVE

Perineural invasion (PNI) negatively affects disease-specific survival in patients with head and neck cutaneous squamous cell carcinoma (HNcSCC). We aim to analyze the prognostic implications of PNI-related features.

STUDY DESIGN

Retrospective cohort study.

SETTING

Academic tertiary care hospital.

METHODS

Retrospective chart review was performed on 104 patients diagnosed with HNcSCC between January 2011 and October 2019 who underwent resection, parotidectomy, and neck dissection with more than 1 year of follow-up. PNI was classified as incidental (identified on histopathology alone) or clinical (present on radiography and/or physical exam). Primary outcome measures were overall survival and disease-free survival (DFS). Kaplan-Meier analysis, logistic regression, and Cox regression were performed.

RESULTS

The overall 5-year DFS was 57.9%. Sixty-one patients had PNI. On histopathology, 28 lesions showed complete nerve encirclement, 10 involved >5 nerves, and 12 involved named nerves. Patients with facial weakness (P = .026) and positive margins (P = .0029) had a higher likelihood of histopathologic PNI, and positive margins retained significance on multivariable analysis (P = .0079). Worse DFS was seen in patients with PNI (P = .004), advanced tumor stage (P = .049), positive margins (P = .014), and >5 nerves involved (P = .0061). Furthermore, histopathologic PNI was a predictor of DFS (hazard ratio [HR], 3.07; 95% CI, 0.33-1.38; P = .0061) overall and in the clinical PNI cohort (HR, 3.43; 95% CI, 1.65-7.10; P = .00091).

CONCLUSION

DFS was significantly worse in patients with PNI, facial nerve weakness, advanced T stage, positive margins, and multiple nerve involvement. Further characterization of PNI features may help improve prognostic predictions and identify patients who may benefit from more aggressive treatment.

Clinical Perineural Invasion and Immunotherapy for Head and Neck Cutaneous Squamous Cell Carcinoma

OBJECTIVES/HYPOTHESIS

To describe outcomes of advanced head and neck cutaneous squamous cell carcinoma (cSCC) with clinical perineural invasion (cPNI) treated with immune checkpoint inhibitor (ICI) therapy, and to describe post-treatment radiographic findings in the context of clinical response to treatment using a new grading system.

STUDY DESIGN

Retrospective chart review.

METHODS

Retrospective chart review was performed for 11 patients treated with ICI for head and neck cSCC with cPNI of large named nerves. The primary outcome was response to treatment as defined by radiographic and clinical evidence. Clinical responses were defined as improvement in symptoms of neuropathic pain, hypoesthesia, nerve weakness, or decrease in visible tumor. Imaging studies were graded based on a new classification system for perineural invasion and reviewed by two neuroradiologists since RECISTv1.1 is inadequate to adjudicate response in these patients.

RESULTS

Nine (82%) patients had radiographic perineural disease control on ICI. Eight patients had improved radiographic perineural disease and one had stable disease. Of these, complete resolution of radiographic evidence of perineural disease was seen in only one patient. Seven (64%) patients had clinical responses, with either improved or stable radiographic disease.

CONCLUSIONS

ICI therapy is a viable treatment option for head and neck cSCC with cPNI. Radiographic and clinical evidence of response correlate well, with improvement in neuropathic pain being the most sensitive clinical marker of response. Even with favorable findings on repeat imaging and stable clinical course, complete resolution of perineural thickening and enhancement is rare. A grading system for classifying changes in perineural disease over time is proposed.

LEVEL OF EVIDENCE

4 Laryngoscope, 2021.

Squamous and basal cell carcinoma with perineural invasion: pathophysiology and presentations

Squamous and basal cell carcinomas with perineural invasion are typically difficult to treat because of their propensity to metastasize, their aggressive nature, and the concept of skip lesions. Perineural invasion is an under-recognized and underdiagnosed condition even though the literature points to its high rate of incidence in squamous cell carcinoma and a nonnegligible incidence rate in basal cell carcinoma. Perineural invasion has been linked to higher recurrence rates and poorer prognosis. This review has been written to aid clinicians in identifying and managing the condition as early as possible by describing the clinical and microscopic manifestations of perineural invasion.

Decompression of Cavernous Sinus for Trigeminal Neuropathic Pain From Perineural Spread of Tumor: 2-Dimensional Operative Video

Head and neck malignancies with perineural spread are rare. Patients can present with neuropathic pain and cranial nerve palsies.1 Skull base approaches for surgical decompression are a consideration for patients to provide symptom relief.2 We demonstrate a frontotemporal extradural approach for a patient with worsening visual symptoms and refractory neuropathic pain in the V1, V2, and V3 distributions and briefly review the relevant anatomy.3-7  A 41-yr-old female with a poorly differentiated carcinoma of the head and neck with an infiltration of the cavernous sinus and perineural spread along the trigeminal nerve presented with severe neuropathic facial pain and anesthesia. She had previously undergone radiosurgery. Magnetic resonance imaging (MRI) demonstrated an interval increase in perineural disease within the cavernous sinus with extension intradurally. Her pain was medically refractory. A 2-dimensional intraoperative video illustrates the microsurgical decompression of her perineural invasion along the skull base as a palliative procedure. The patient recovered well postoperatively and had a symptomatic improvement in her pain and visual symptoms. Her preoperative facial numbness persisted postoperatively as expected. Postoperative imaging demonstrates a gross total resection of the intradural component of the tumor with decompression and expected expansion of the cavernous sinus. Because of the retrospective nature of this report, informed consent was not required. Images within the video have been reproduced from Fukuda et al4 with permission from © Georg Thieme Verlag KG; and Matsuo et al5 by permission of the Congress of Neurological Surgeons.

Malignancies requiring temporal bone resection: An Australian single-institution experience

BACKGROUND

Malignancies in and around the temporal bone are aggressive and difficult to manage. In Queensland (Australia), where skin cancer rates are exceedingly high, tumours extending to the temporal bone from surrounding structures occur more commonly than primary cancers. Yet, a paucity of evidence exists as to their management and outcomes. This study aimed to review an Australian centre's experience of managing temporal and peritemporal bone malignancies, reporting on patient and tumour characteristics, treatment, and survival outcomes.

METHODS

Retrospective analysis of patients with primary temporal bone cancer and cancers extending to the temporal bone managed by the Queensland Skull Base Unit (Princess Alexandra Hospital) between 2000 and 2019.

RESULTS

A total of 222 patients were identified, of which 203 (91.4%) had cutaneous primaries, with 167 (75.2%) being squamous cell carcinoma (SCC). 73.9% presented with locoregionally recurrent or residual disease. Secondary tumours (92.8%) were 12 times more frequent than primary malignancies (7.2%), with the preauricular subsite the most common (45.5%). In the 201 patients (90.5%) who underwent curative intent surgery, 5-year overall survival, disease-free survival (DFS), and disease-specific survival was 46.6%, 52.2%, and 65.9%, respectively. The preauricular subsite (p = 0.004), melanoma (vs. SCC, p = 0.027), involved margins (p < 0.001), and pathologically involved nodes (p < 0.001) were associated with significantly worse DFS.

CONCLUSION

This is one of the largest studies of temporal bone malignancy in the literature, comprised primarily of secondary cutaneous malignancies. Although clear differences in epidemiological characteristics exist around the world, survival remains poor. Treatment should focus on achieving a clear margin of resection to optimize outcomes.

A direct transcutaneous approach to infraorbital nerve biopsy

Purpose: To describe a novel transcutaneous infraorbital nerve biopsy technique which can be performed to aid in the diagnosis of perineural invasion (PNI) of facial cutaneous squamous cell carcinoma (SCC).Methods: A single-center retrospective chart review was performed. Patients diagnosed with SCC with PNI via an infraorbital nerve biopsy between February 2019 and February 2020 were included. Data collected consisted of patient demographics, medical history, clinical presentation and exam, histologic and radiographic findings, treatment, and outcomes.Results: Four patients (3 male, 1 female) met inclusion criteria. The mean age at diagnosis was 79.5 years (range 66-85 years). Three of the four patients had a history of facial skin lesions, including actinic keratosis and SCC, involving the nose, cheek, or ear. One patient had no history of cutaneous malignancy. All patients presented with cranial neuropathies, including total V2 hypoesthesia. The most common presenting symptom was facial pain, followed by diplopia, unilateral facial weakness, and hypoesthesia in the V1 and/or V2 distribution. Transcutaneous infraorbital nerve biopsy in all patients revealed squamous cell carcinoma with no biopsy complications.Conclusion: Definitive diagnosis of PNI can be challenging but is important to minimize tumor-related morbidity. Infraorbital nerve biopsy can establish this diagnosis, especially in the context of negative or indeterminate imaging findings. This work comprises the first description of a transcutaneous approach to infraorbital nerve biopsy, which is a minimally invasive technique that can be performed in an outpatient procedure suite with limited to no sedation.

Adenoid cystic carcinoma: a review of clinical features, treatment targets and advances in improving the immune response to monoclonal antibody therapy

The natural history of adenoid cystic carcinoma (ACC) is relentless, defined by treatment failure heralded by locoregional recurrence and distant metastatic disease. In this review, we present an update of clinical features, molecular classification, current targeted therapies, immune landscapes and novel treatment targets with their respective clinical trials. The presented results are defined by a lack of overall response rate and limited progression free survival, with restriction to stable disease. In addition, ACC is resistant to immune checkpoint inhibition due to low tumour immunogenicity and lack of PD-L1 expression. Here we present a new prospective research paradigm for ACC, including the potential to target prostate specific membrane antigen (PSMA) and the potential for manipulation of target receptors in the clinic. The presentation of this review aims to promote future research to improve response rates and outcomes for therapeutics undergoing clinical trial in ACC.

Outpatient surgical management of non-melanoma skin cancers of the head and neck in a regional centre: an analysis of costs and outcomes

BACKGROUND

Non-melanoma skin cancer is the most commonly diagnosed malignancy in Australia. Lesions of the head and neck are often outside the scope of primary care providers. The challenges of cancer care in regional Australia necessitate careful resource planning. This study presents an outpatient model that minimizes health service cost with local general practitioner follow-up.

METHODS

A retrospective review of 105 patients with 122 skin lesions in a dedicated Facial Lesion Assessment Management and Excision clinic was performed from July 2018 to 2019. Clinical outcomes, patient travel and cost analysis/comparison were recorded.

RESULTS

There were 85 malignant cases with 59 basal cell carcinomas and 25 squamous cell carcinomas. For basal cell carcinoma, clear margins (≥3 mm), close margins (<3 mm) and positive margins were achieved in 24 (48%), 23 (46%) and three (6%) cases, respectively. For squamous cell carcinoma, clear margins (≥5 mm), close margins (<5 mm) and positive margins were achieved in seven (38.8%), 11 (61.1%) and none (0%) of the cases, respectively. Complications included one haematoma and two wound infections. For 37% of patients living >100 km from the department, 72.3% had local general practitioner follow-up. Inpatient cost was $2870, $5697 and $9300 for primary closure, local flap and full-thickness skin graft, respectively, and outpatient cost was $746 for a single facial lesion.

CONCLUSION

This study presents a cost-effective model for the management of non-melanoma skin cancers with improved departmental efficiency and streamlined patient care in an outpatient skin cancer management model in a regional centre.

The biology and engineered modeling strategies of cancer-nerve crosstalk

A recent finding critical to cancer aggravation is the interaction between cancer cells and nerves. There exist two main modes of cancer-nerve interaction: perineural invasion (PNI) and tumor innervation. PNI occurs when cancer cells infiltrate the adjacent nerves, and its relative opposite, tumor innervation, occurs when axons extend into tumor bodies. Like most cancer studies, these crosstalk interactions have mostly been observed in patient samples and animal models at this point, making it difficult to understand the mechanisms in a controlled manner. As such, in recent years in vitro studies have emerged that have helped identify various microenvironmental factors responsible for cancer-nerve crosstalk, including but not limited to neurotrophic factors, neurotransmitters, chemokines, cancer-derived exosomes, and Schwann cells. The versatility of in vitro systems warrants continuous development to increase physiological relevance to study PNI and tumor innervation, for example by utilizing biomimetic three-dimensional (3D) culture systems. Despite the wealth of 3D in vitro cancer models, comparatively there exists a lack of 3D in vitro models of nerve, PNI, and tumor innervation. Native-like 3D in vitro models of cancer-nerve interactions may further help develop therapeutic strategies to curb nerve-mediated cancer aggravation. As such, we provide an overview of the key players of cancer-nerve crosstalk and current in vitro models of the crosstalk, as well as cancer and nerve models. We also discuss a few future directions in cancer-nerve crosstalk research.

Imaging of the post-treatment neck

Post-treatment imaging of the neck is complex. It is important to have an understanding of the expected treatment related appearances as well as the possible complications. Common findings after radiation therapy include generalised soft-tissue oedema and thickening of the skin and platysma muscle. There are a number of complications of radiation that may be seen on imaging, including osteoradionecrosis, chondronecrosis, and accelerated atherosclerosis. Surgical procedures are variable depending on the primary tumour site and extent. The use of flap reconstructions can further complicate the imaging appearances. Any new nodule of enhancement or bone/cartilage erosion should raise concern for tumour recurrence. It is also important to assess for nodal recurrence. A standardised approach to reporting may help to increase accuracy and guide treatment decisions.

Prevalence of Perineural Invasion in keratinocyte cancer in the general population and among organ transplant recipients

BACKGROUND/OBJECTIVES

Basal cell carcinomas (BCCs) and cutaneous squamous cell carcinomas (SCCs) are the most commonly encountered cancers in fair-skinned populations worldwide. Perineural invasion is associated with worse outcomes for patients with BCC or SCC. Estimates of perineural invasion prevalence range widely, likely reflecting non-representative patient samples. We sought to determine the prevalence of perineural invasion in BCC and SCC in the general population, as well as among cancers arising in solid organ transplant recipients.

METHODS

We retrospectively analysed histopathology reports of BCC and SCC from patients enrolled in the QSkin Study (a population-based cohort of 43 794 Queensland residents recruited 2010-2011) and the Skin Tumours in Allograft Recipients (STAR) study (a cohort of 509 high-risk kidney or liver transplant recipients at the Princess Alexandra Hospital, Brisbane, recruited 2012-2014.) We estimated the prevalence of perineural invasion (and 95% confidence interval) in BCC and SCC, respectively, and identified clinical factors associated with perineural invasion.

RESULTS

In QSkin, we observed 35 instances of perineural invasion in 9850 histopathologically confirmed BCCs (0.36%) and 9 instances of perineural invasion in 3982 confirmed SCC (0.23%) lesions. In the STAR cohort, we identified 4 lesions with perineural invasion in 692 BCCs (0.58%) and 16 reports of perineural invasion in 875 SCC lesions (1.9%).

CONCLUSIONS

These data suggest that the overall prevalence of perineural invasion in keratinocyte cancer is low, although perineural invasion prevalence may be slightly higher among organ transplant recipients when compared to the general population.

Management of advanced adenoid cystic carcinoma infiltrating the skull base: a contemporary review

INTRODUCTION

This article provides an overview of the natural history and management of adenoid cystic carcinoma infiltrating the skull base (SB ACC).

METHODS

A comprehensive review of the available literature and discussion regarding the current management of SB ACC.

RESULTS

This review describes the unique pathology, appropriate diagnostic work-up and contemporary management options in SB ACC. There is a specific focus on the role of surgical resection with post-operative radiotherapy, given the literature suggesting a superior locoregional control rate. The importance of surgical decision making and varying surgical approaches are detailed. In addition, the emerging role of biological agents is discussed.

CONCLUSION

The gold standard for SB ACC is surgical resection and post-operative radiation, given the superior locoregional control. In patients not amendable to surgery, palliative radiation should be considered. The role of biological agents is still evolving. The complexity of SB ACC management mandates experienced multi-speciality management.

Solitary Metastasis of Adenocarcinoma of Submandibular Gland to Choroid Plexus in Cerebellopontine Angle: First Case Reported in Literature

BACKGROUND

Adenocarcinoma of the salivary gland (AdCASG) is a rare and malignant tumor of the salivary glands. Albeit, metastatic lesions occur anecdotally in the choroid plexus and most rarely in the cerebellopontine angle (CPA). We report the first case of metastatic AdCASG to the choroid plexus of the lateral recess of the fourth ventricle located in CPA, emphasizing the clinical presentation and neuroradiologic findings.

CASE DESCRIPTION

A 40-year-old man was referred with signs of increased intracranial pressure and a unilateral hearing problem. Magnetic resonance imaging showed a pear-shaped, vividly enhancing tumor in the left CPA. The tumor was a metastatic AdCASG. Gross total resection of the lesion was followed by a conventional radiotherapy lead in a 5-year tumor-free control interval.

CONCLUSIONS

Metastatic lesions to the choroid plexus may show a pedunculated shape in magnetic resonance imaging. It is hypothesized that tumor seeding may occur through the veins, lymphatics, and nerve sheaths in the skull base region. Tissue specimen is necessary to confirm such rare pathology.

Evaluating Perineural Spread to the Intratemporal Facial Nerve on Magnetic Resonance Imaging

Objectives

To determine the sensitivity and specificity of magnetic resonance imaging (MRI) for the detection of perineural spread (PNS) along the intratemporal facial nerve (ITFN) in patients with head and neck cancers.

Study Design

Case series with chart review.

Setting

Tertiary care center.

Subjects and Methods

We included 58 patients with head and neck malignancies who underwent sacrifice of the ITFN between August 1, 2002, and November 30, 2015. Demographics, preoperative facial nerve function, prior oncologic treatment, and timing between MRI and surgery were recorded. Histopathology slides and preoperative MRI were reviewed retrospectively by a neuropathologist and a neuroradiologist, respectively, both blinded to clinical data. The mastoid segment of the facial nerve (referred to as the descending facial nerve [DFN]) and stylomastoid foramen (SMF) were evaluated separately. A grading system was devised when radiographically assessing PNS along the DFN.

Results

Histopathologic evidence of PNS was found in 21 patients (36.2%). The sensitivity and specificity of MRI in detecting PNS to the DFN were 72.7% and 87.8%, respectively. MRI showed higher sensitivity but slightly lower specificity when evaluating the SMF (80% and 82.8%, respectively). Prior oncologic treatment did not affect the false-positive rate ( P = .7084). Sensitivity was 100% when MRI was performed within 2 weeks of surgery and was 62.5% to 73.3% when the interval was greater than 2 weeks. This finding was not statistically significant (SMF, P = .7076; DFN, P = .4143).

Conclusion

MRI shows fair to good sensitivity and good specificity when evaluating PNS to the ITFN.

Endoscopic anterior transmaxillary "transalisphenoid" approach to Meckel's cave and the middle cranial fossa: an anatomical study and clinical application

OBJECTIVE Multiple approaches have been designed to reach the medial middle fossa (for lesions in Meckel's cave, in particular), but an anterior approach through the greater wing of the sphenoid (transalisphenoid) has not been explored. In this study, the authors sought to assess the feasibility of and define the anatomical landmarks for an endoscopic anterior transmaxillary transalisphenoid (EATT) approach to Meckel's cave and the middle cranial fossa. METHODS Endoscopic dissection was performed on 5 cadaver heads injected intravascularly with colored silicone bilaterally to develop the approach and define surgical landmarks. The authors then used this approach in 2 patients with tumors that involved Meckel's cave and provide their illustrative clinical case reports. RESULTS The EATT approach is divided into the following 4 stages: 1) entry into the maxillary sinus, 2) exposure of the greater wing of the sphenoid, 3) exposure of the medial middle fossa, and 4) exposure of Meckel's cave and lateral wall of the cavernous sinus. The approach provided excellent surgical access to the anterior and lateral portions of Meckel's cave and offered the possibility of expanding into the infratemporal fossa and lateral middle fossa and, in combination with an endonasal transpterygoid approach, accessing the anteromedial aspect of Meckel's cave. CONCLUSIONS The EATT approach to Meckel's cave and the middle cranial fossa is technically feasible and confers certain advantages in specific clinical situations. The approach might complement current surgical approaches for lesions of Meckel's cave and could be ideal for lesions that are lateral to the trigeminal ganglion in Meckel's cave or extend from the maxillary sinus, infratemporal fossa, or pterygopalatine fossa into the middle cranial fossa, Meckel's cave, and cavernous sinus, such as schwannomas, meningiomas, and sinonasal tumors and perineural spread of cutaneous malignancy.

Imaging-Ambiguous Lesions of Meckel's Cave-Utility of Endoscopic Endonasal Transpterygoid Biopsy

INTRODUCTION

Meckel's cave is a dural-lined cavity in the middle fossa skull base in which lies the Gasserian ganglion, a potential site for tumors and inflammatory lesions. A variety of lesions can be predominantly isolated to Meckel's cave, including extension from head and neck cancers, other malignant tumors, as well as benign lesions. Clinical presentation and imaging findings are often insufficient to establish a diagnosis. Hence, histologic confirmation is required to determine the appropriate treatment strategy. Several surgical approaches have been used to reach this deep-seated area, often with significant morbidity and prolonged recovery. Given advancements in endoscopy and greater facility with the technique, the endoscopic endonasal approach has been used increasingly to reach lesions in the region.

METHODS

A single-institution, retrospective chart review over a 10-year period was performed to identify and describe patients with pathologically differing but imaging-similar lesions with their epicenter in Meckel's cave.

RESULTS

Of a total of 21 cases of lesions in Meckel's cave approached by an endoscopic endonasal transpterygoid approach, we present 6 patients with imaging-ambiguous lesions involving Meckel's cave that were biopsied via the extended endoscopic endonasal approach. Among this diverse group, pathology included B-cell lymphoma, squamous cell carcinoma, adenocarcinoma, malignant schwannoma, benign schwannoma, and neurosarcoidosis.

CONCLUSIONS

We explore not only the relevance of this approach in the armamentarium of the modern skull-base surgeon but also its limitations and conclude that the endoscopic endonasal approach provides a safe and relatively direct, minimally invasive corridor to many lesions of Meckel's cave.

Bell's Palsy

PURPOSE OF REVIEW

Bell's palsy is a common outpatient problem, and while the diagnosis is usually straightforward, a number of diagnostic pitfalls can occur, and a lengthy differential diagnosis exists. Recognition and management of Bell's palsy relies on knowledge of the anatomy and function of the various motor and nonmotor components of the facial nerve. Avoiding diagnostic pitfalls relies on recognizing red flags or features atypical for Bell's palsy, suggesting an alternative cause of peripheral facial palsy.

RECENT FINDINGS

The first American Academy of Neurology (AAN) evidence-based review on the treatment of Bell's palsy in 2001 concluded that corticosteroids were probably effective and that the antiviral acyclovir was possibly effective in increasing the likelihood of a complete recovery from Bell's palsy. Subsequent studies led to a revision of these recommendations in the 2012 evidence-based review, concluding that corticosteroids, when used shortly after the onset of Bell's palsy, were "highly likely" to increase the probability of recovery of facial weakness and should be offered; the addition of an antiviral to steroids may increase the likelihood of recovery but, if so, only by a very modest effect.

SUMMARY

Bell's palsy is characterized by the spontaneous acute onset of unilateral peripheral facial paresis or palsy in isolation, meaning that no features from the history, neurologic examination, or head and neck examination suggest a specific or alternative cause. In this setting, no further testing is necessary. Even without treatment, the outcome of Bell's palsy is favorable, but treatment with corticosteroids significantly increases the likelihood of improvement.

Significance of perineural invasion in locally advanced bucco alveolar complex carcinomas treated with surgery and postoperative radiation ± concurrent chemotherapy

BACKGROUND

The purpose of this study was to evaluate prognostic factors, locoregional control, and survival in locally advanced bucco-alveolar complex cancers.

METHODS

A retrospective review of 83 patients treated between January 2009 and December 2012 with bucco-alveolar complex cancers was conducted. All patients had surgery and adjuvant radiotherapy with intensity-modulated radiotherapy (IMRT) with/without concurrent chemotherapy. Survival analysis was performed using Kaplan-Meier and multivariable Cox regression model.

RESULTS

On univariate and multivariate analysis, perineural invasion (PNI) was found to be an independent adverse risk factor. Patients with PNI-positive disease had significantly worse 2-year disease-free survival (DFS), locoregional failure free survival, and overall survival (OS) as compared to patients with PNI-negative disease (P < 0. 001, 0.001 and < 0. 001) respectively.

CONCLUSION

Compared with patients with PNI-negative disease, patients with PNI-positive disease had much worse outcome despite aggressive adjuvant treatment. It warrants escalation of therapy and modification in radiation portals to cover neural pathways in patients with PNI-positive disease.

AHNS Series: Do you know your guidelines? Principles of surgery for head and neck cancer: A review of the National Comprehensive Cancer Network guidelines

This article continues a series developed by the American Head and Neck Society's Education Committee entitled "Do you know your guidelines?" It is hoped that these features will increase awareness of and adherence to current best practices in head and neck cancer care. In this installment, the National Comprehensive Cancer Network (NCCN) guidelines for surgical therapy are reviewed. © 2016 Wiley Periodicals, Inc. Head Neck 39: 791-796, 2017.

Skull Base Invasion Patterns and Survival Outcomes of Nonmelanoma Skin Cancers

Objective Report routes of skull base invasion for head and neck nonmelanoma skin cancers (NMSCs) and their survival outcomes. Design Retrospective. Participants Ninety patients with NMSC with skull base invasion between 2004 and 2014. Major Outcome Measures Demographic, tumor characteristics, and treatments associated with different types of skull base invasion and disease-specific survival (DSS) and overall survival (OS). Results Perineural invasion (PNI) to the skull base occurred in 69% of patients, whereas 38% had direct skull base invasion. Age, histology, orbital invasion, active immunosuppression, cranial nerve (CN) involved, and type of skull base invasion were significantly associated with DSS and OS (p < 0.05). Patients with basal cell carcinoma (BCC) had significantly improved DSS and OS compared with other histologies (p < 0.05). Patients with CN V PNI had significantly improved DSS and OS compared with CN VII PNI (p < 0.05). Patients with zone II PNI had significantly improved DSS and OS compared with those with direct invasion or zone III PNI (p < 0.05). Nonsurgical therapy was rarely used and is associated with a reduction in DSS and OS (p < 0.05). Conclusion Patterns and survival outcomes for NMSC skull base invasion are reported. Zone II PNI, BCC, and CN V PNI are associated with improved survival outcomes.

Reconstruction of the Base of Skull Defect-Lessons Learned over 25 Combined Years

With an increased understanding of the pathological processes involved in perinerual spread, surgery has come to play a greater role in its management. As skull base techniques have been refined, the reconstructive surgeon has been presented with increasingly complex and voluminous defects requiring repair. To enable such surgery to have acceptable outcomes, attention to form and function is paramount. This article describes the methods of repair, which have evolved over the last 25 years of practice, and that we find to be both reliable and durable. Our accumulated experience is presented as a treatment algorithm, which will aid the skull base reconstructive surgeon to achieve success for the wide variety of defects encountered with these patients.