Squamous epithelial changes of the larynx: Diagnosis and therapy

Predictive factors of frozen section in transoral microlaryngeal surgery for suspicious glottic lesions

OBJECTIVE

Frozen biopsy may guide surgical intraoperative decisions. We evaluated the accuracy of frozen biopsy for diagnosing benign, dysplastic and malignant laryngeal lesions, compared to paraffin section (gold standard).

METHODS

Retrospective review of the charts of all patients presenting with laryngeal lesions suspicious of malignancy, who underwent laryngeal microsurgery with frozen biopsy in our institution, between 2015 and 2020. Results of frozen biopsy and paraffin section examinations were compared.

RESULTS

Among 113 samples of 89 patients, paraffin section diagnosed 23 benign, 31 dysplastic and 59 malignant lesions. The accuracy of the frozen biopsy in identifying dysplasia or malignancy was 80.5% (91/113), and greater for lesions >5 mm (78.8% × 51.5%; p = 0.009). The positive and negative predictive values, sensitivity and specificity were 95.9%, 51.3%, 78.9% and 86.9%, respectively.

CONCLUSIONS

Frozen section is a reliable tool when malignancy is detected, but almost half of benign results exhibit dysplasia or malignancy in paraffin section. Other clinical parameters should be considered in intraoperative decisions to prevent undertreatment.

LEVEL OF EVIDENCE: 4

Laryngeal Dysfunction Manifesting as Chronic Refractory Cough and Dyspnea: Laryngeal Physiology in Respiratory Health and Disease

TOPIC IMPORTANCE

Laryngeal dysfunction as a cause of chronic refractory cough (CRC) and episodic dyspnea is often missed, which results in unnecessary testing and delays in diagnosis. Understanding laryngeal roles in breathing and airway protection can help to appreciate the propensity to laryngeal dysfunction with aging, chronic lung disease, and sleep apnea.

REVIEW FINDINGS

The human larynx is a complex muscular structure that is responsible for multiple roles of breathing, vocalization, coughing, and swallowing. To undertake these activities, the larynx has a high density of sensory and motor innervation. In addition to common embryological origins with the pharynx and esophagus, with which many laryngeal activities are shared, somatomotor and autonomic pathways regulate emotional, cognitive, and complex motor sequence-planning activities within the larynx. Due to its unique location, the larynx is susceptible to infectious and gastroesophageal reflux-related insults. Couple this with key roles in regulation of airflow and mediation of airway protective reflexes, it is not surprising that neuropathic abnormalities and muscle dysfunction frequently develop. The expression of laryngeal dysfunction as hypersensitivity to mechanical, thermal, chemical, and other stimuli leads to exaggerated airway protective reflexes (laryngeal adductor reflex and cough reflex) manifesting as dyspnea and cough.

SUMMARY

Pulmonologists should incorporate assessment of laryngeal dysfunction during evaluation of CRC and dyspnea. Recognition of laryngeal hypersensitivity in patient with CRC can identify patients who may benefit from cough suppression therapies. Similarly, timely identification of inducible laryngeal obstruction may not only resolve episodic dyspnea but lessen the need for unnecessary testing and treatments.

Tracheobronchial mucosal keratosis: A literature review of this rare disorder

Background

Tracheobronchial mucosal keratosis (TBMK) is a rare airway disease that may cause refractory cough and airway stenosis. The characteristics of this disease remain unknown. In the present study, we describe this disorder based on a review of the current literature, emphasizing its diagnostic and therapeutic aspects.

Methods

A comprehensive search of TBMK was performed in Medline, Google Scholar, Web of Science, Cochrane Library (UK), Embase, China National Knowledge Infrastructure (CNKI) (China), and Wan Fang Med Online (China). The following data were collected: patient characteristics, chest imaging findings, bronchoscopy, histopathologic findings, pathogen testing, treatment, and prognosis.

Results

As of 2023, eighteen cases of TBMK have been reported. The main clinical manifestations were cough and expectoration. Chest imaging findings were non-specific. The main bronchoscopy findings were nodular protrusion of airway lumen and yellow-white purulent moss above the nodular lesion. The lesions were mainly located in the trachea and mainstem bronchus. The main pathological manifestations include keratinocytes or keratinocyte beads, squamous metaplasia, and mucosal inflammatory changes. The treatments that were administered include antibiotics, symptomatic treatment, and glucocorticoids. All methods were ineffective except for bronchoscopy-guided high-frequency electric knife and recombinant human epidermal growth factor treatment.

Conclusions

TBMK is a rare respiratory disease with atypical clinical manifestations and chest computed tomography findings. Bronchoscopy revealed that nodular hyperplasia of the airway and purulent fur-covered lesions are typical manifestations. The final diagnosis needs to be confirmed by histopathological examination. There is a lack of effective treatment for this disease, and bronchoscopy-guided intervention therapy may be a candidate treatment.

Dysplastic Lesions of the Larynx

There have been many advancements in the clinical and histologic diagnosis of laryngeal dysplasia (LD), but diagnosis still necessitates invasive histologic evaluation. Furthermore, despite improved histologic identification of dysplastic lesions, the exact details of pathophysiologic progression and the risk of malignant transformation is still uncertain. These unknowns create a barrier to establishing an ideal grading and classification system, which prevents the establishment of a precise and consistent treatment paradigm. Identifying these gaps in knowledge serves to highlight where further studies are warranted, ideally focusing on a better understanding of the biological behavior of LD. This would ultimately allow for the creation of a reliable grading and classification system and for the formalization of management and treatment guidelines for LD.

Vocal Folds Leukoplakia: The Efficacy of Vitamin A in the Initial Treatment

Introduction  Laryngeal leukoplakia corresponds to a white lesion in the mucosa developed by the deposit of keratin in the epithelium, potentiated by chronic smoking. It is considered a preneoplastic lesion. Surgery is the most adopted treatment; however, non-surgical treatment is advocated by some authors. Objective  To evaluate the effectiveness of vitamin A in the management of vocal fold leukoplakia. Methods  Patients with videolaryngoscopy diagnosis of vocal fold leukoplakia were selected. The endoscopic images were photographed and with the aid of the ImageJ software (National Institutes of Health, Bethesda, MD, USA), the proportion of the size of the leukoplakia was calculated. Eligible patients were prescribed 50,000U of vitamin A, twice daily for 2 months, at which point videolaryngostroboscopy was repeated for comparative analysis between pre and posttreatment. The efficacy of the treatment was classified as: outcome I - complete improvement of the lesion, outcome II - partial improvement, and outcome III - no difference or increased lesion size. Results  Fifteen patients (eight women, seven men) were included, six of whom had bilateral lesions. Smoking was reported in 86.8% of patients. Complete improvement of the lesion was found in 7 cases (33.4%, outcome I), partial improvement in 6 (28.6%, outcome II), and worsening of the injury in 8 (38.1%, outcome III). Of the latter, 6 underwent microsurgery; histopathology indicated absence of dysplasia in 3, and mild dysplasia in 3. Conclusions  In this study, the treatment with vitamin A at a dose of 100,000 IU daily for 2 months was effective in reducing the laryngeal leukoplakia size in 62% of cases.

Exposure to e-cigarette vapor extract induces vocal fold epithelial injury and triggers intense mucosal remodeling

Vaping has been reported to cause acute epiglottitis, a life-threatening airway obstruction induced by direct epithelial injury and subsequent inflammatory reaction. Here, we show that we were able to recapitulate this phenomenon in vitro. Exposure of human engineered vocal fold (VF) mucosae to 0.5% and 5% electronic cigarette (e-cigarette) vapor extract (ECVE) for 1 week induced cellular damage of luminal cells, disrupting homeostasis and innate immune responses. Epithelial erosion was likely caused by accumulation of solvents and lipid particles in the cytosol and intercellular spaces, which altered lipid metabolism and plasma membrane properties. Next, we investigated how the mucosal cells responded to the epithelial damage. We withdrew the ECVE from the experimental system and allowed VF mucosae to regenerate for 1, 3 and 7 days, which triggered intense epithelial remodeling. The epithelial changes included expansion of P63 (TP63)-positive basal cells and cytokeratin 14 (KRT14) and laminin subunit α-5 (LAMA5) deposition, which might lead to local basal cell hyperplasia, hyperkeratinization and basement membrane thickening. In summary, vaping presents a threat to VF mucosal health and airway protection, thereby raising further concerns over the safety of e-cigarette use.

This article has an associated First Person interview with the first author of the paper.

Editor's choice: Exposure of vocal fold mucosae to e-cigarette vapor extract induces lipid-mediated epithelial injury that disrupts vocal fold mucosal homeostasis and innate barrier function and triggers intense mucosal remodeling.

Developing Classifications of Laryngeal Dysplasia: The Historical Basis

During the last 60 years numerous significant attempts have been made to achieve a widely acceptable terminology and histological grading for laryngeal squamous intraepithelial lesions. While dysplasia was included in the pathology of the uterine cervix already in 1953, the term dysplasia was accepted in laryngeal pathology first after the Toronto Centennial Conference on Laryngeal Cancer in 1974. In 1963 Kleinsasser proposed a three-tier classification, and in 1971 Kambic and Lenart proposed a four-tier classification. Since then, four editions of the World Health Organisation (WHO) classification have been proposed (1978, 1991, 2005 and 2017). Several terms such as squamous intraepithelial neoplasia (SIN) and laryngeal intraepithelial neoplasia (LIN) are now being abandoned and replaced by squamous intraepithelial lesions (SIL). The essential change between the 2005 and 2017 WHO classifications is the attempt to induce a simplification from a four- to a two-tier system. The current WHO classification (2017) thus recommends the use of a two-tier system with reasonably clear histopathological criteria for the two groups: low-grade and high-grade dysplasia. Problems with interobserver variability apart, subjectivities and uncertainties remain, but to a lesser degree. Ongoing and additional molecular studies may help to clarify underlying events that will increase our understanding and possibly can facilitate our attempts to obtain an even better classification. The classification needs to be easier for the general pathologist to perform and easier for the clinician to interpret. These two objectives are equally important to provide each patient the best personalised treatment available for squamous intraepithelial lesions.

Laryngeal Dysplasia: Persisting Dilemmas, Disagreements and Unsolved Problems-A Short Review

We present the historical review and current state of the histopathological classifications and terminology of laryngeal precursor lesions. Attention to recent genetic findings is also presented; although in need of additional confirmation, these raise possibility for early detection of patients at risk of dysplasia progression. Although a number of identified genetic alterations with a promising diagnostic and prognostic value are emerging, none of the known genetic alterations can be currently implemented in clinical practice as a completely reliable diagnostic and/or prognostic marker. Regarding the terminology of precursor lesions, dysplasia remains the most frequently used term, but squamous intraepithelial lesion can be used as a synonym as well. Histological findings, in spite of certain degree of subjectivity, remain at present the most reliable method for an accurate diagnosis. The current 2017 WHO classification seems to successfully stratify risk of malignant progression, with a significantly different risk of malignant progression between low-grade dysplasia and high-grade dysplasia. In case of pronounced architectural disorders, severe cellular and nuclear atypias, and an increased number of mitoses, also atypical form, the high-grade dysplasia and carcinoma in situ can be separated. The Slovenian tertiary centers have a policy of surgical removal of high-grade SILs and life-long close follow-up. Radiotherapy is reserved for more pronounced intraepithelial lesions classified as carcinoma in situ and invasive cancer. Such a distinction can facilitate clinical decision to use radiotherapy if complete surgical removal is not possible.

Human induced pluripotent stem cell-derived vocal fold mucosa mimics development and responses to smoke exposure

Development of treatments for vocal dysphonia has been inhibited by lack of human vocal fold (VF) mucosa models because of difficulty in procuring VF epithelial cells, epithelial cells' limited proliferative capacity and absence of cell lines. Here we report development of engineered VF mucosae from hiPSC, transfected via TALEN constructs for green fluorescent protein, that mimic development of VF epithelial cells in utero. Modulation of FGF signaling achieves stratified squamous epithelium from definitive and anterior foregut derived cultures. Robust culturing of these cells on collagen-fibroblast constructs produces three-dimensional models comparable to in vivo VF mucosa. Furthermore, we demonstrate mucosal inflammation upon exposure of these constructs to 5% cigarette smoke extract. Upregulation of pro-inflammatory genes in epithelium and fibroblasts leads to aberrant VF mucosa remodeling. Collectively, our results demonstrate that hiPSC-derived VF mucosa is a versatile tool for future investigation of genetic and molecular mechanisms underlying epithelium-fibroblasts interactions in health and disease.

The White Lesion, Hyperkeratosis, and Dysplasia

Laryngeal mucosal precursor lesions represent a challenging clinical entity. Updated classification systems allow for grade-based categorization. Multiple management options exist, with treatment decisions made jointly by physician and patient and focused on both appropriate lesion treatment and preservation of laryngeal structure and function. Traditional methods include cold steel and CO₂ laser excision, with newer modalities using angiolytic lasers for lesion ablation. Both operating room-based and office-based treatment options exist, and there are advantages and disadvantages to each approach. Research is ongoing to advance the understanding of lesion biology, and to optimize prevention and treatment.

Nonsurgical Treatment for Vocal Fold Leukoplakia: An Analysis of 178 Cases

OBJECTIVE

To assess the effectiveness and identify vocal fold leukoplakia types appropriate for nonsurgical treatment.

METHODS

The vocal fold leukoplakia in 178 patients was divided by gross appearance into three subtypes: flat and smooth, elevated and smooth, and rough. All patients received nonsurgical treatment including smoking and drinking cessation, voice rest, omeprazole, and Chinese medication therapy. The clinical response of three subtypes was assessed after a 6-month follow-up.

RESULTS

Vocal fold leukoplakia subtypes included flat and smooth (n = 66; 37.1%), elevated and smooth (n = 103; 57.9%), and rough (n = 9; 5.0%). The rate of complete response was 80.3%, 66.0%, and 0.0% for the 3 lesion types, respectively (rough versus flat and smooth, P < 0.001; rough versus elevated and smooth, P < 0.001, Fisher's exact test). The incidence of carcinoma in rough leukoplakia was significantly higher than that in smooth leukoplakia (44.4% versus 2.4%, P = 0.002, Fisher's exact test). Clinical type was the only significant factor for clinical response of nonsurgical treatment (P = 0.005, ordinal logistic regression).

CONCLUSIONS

The effectiveness of nonsurgical treatment for smooth vocal fold leukoplakia is better in comparison to rough vocal fold leukoplakia. Smooth leukoplakia could be managed with nonsurgical treatment; more aggressive treatments should be considered for rough leukoplakia.

Guidelines for the Surgical Management of Laryngeal Cancer: Korean Society of Thyroid-Head and Neck Surgery

Korean Society of Thyroid-Head and Neck Surgery appointed a Task Force to develop clinical practice guidelines for the surgical treatment of laryngeal cancer. This Task Force conducted a systematic search of the EMBASE, MEDLINE, Cochrane Library, and KoreaMed databases to identify relevant articles, using search terms selected according to the key questions. Evidence-based recommendations were then created on the basis of these articles. An external expert review and Delphi questionnaire were applied to reach consensus regarding the recommendations. The resulting guidelines focus on the surgical treatment of laryngeal cancer with the assumption that surgery is the selected treatment modality after a multidisciplinary discussion in any context. These guidelines do not, therefore, address non-surgical treatment such as radiation therapy or chemotherapy. The committee developed 62 evidence-based recommendations in 32 categories intended to assist clinicians during management of patients with laryngeal cancer and patients with laryngeal cancer, and counselors and health policy-makers.

Diagnostic Variability of Laryngeal Premalignant Lesions

Objective

This study was to analyze the interobserver histopathological variability and carcinoma transformation of laryngeal premalignant lesions.

Study Design

A historical cohort study.

Setting

Department of Pathology, Beijing TongRen Hospital, Capital Medical University, Beijing, China.

Subjects and Methods

κ-statistics analysis was performed to estimate interobserver histopathological variability among pathologists by reassessment of 237 cases with laryngeal premalignant lesion according to 2005 WHO classification system. A retrospective follow-up of 237 patients over 8-year duration was carried out, and the carcinoma transformation of laryngeal premalignant lesions was analyzed using Kaplan-Meier survival curve estimation.

Results

κ-values of 0.5989 concerning interobserver variability indicated a moderate agreement among 3 pathologists. Major source of intergrade diagnostic disagreement between the original and the consensus diagnoses involved 2 grade pairs, namely, mild and moderate dysplasia, severe dysplasia, and carcinoma in situ. In addition, follow-up study showed that 20 of 237 (8.44%) laryngeal premalignant lesion cases developed into invasive carcinoma. Carcinoma transformation in severe dysplasia group exhibited a similar risk compared to that in carcinoma in situ group ( P = .232).

Conclusion

Severe dysplasia shows the same carcinoma transformation potential as the carcinoma in situ does. Clinically, more attention to severe dysplasia is needed in comparison with mild and moderate dysplasia.

Differentiated dysplasia is a frequent precursor or associated lesion in invasive squamous cell carcinoma of the oral cavity and pharynx

The source of precursor lesions of squamous cell carcinoma (SCC) of the oral cavity and pharynx, their classification, and grading are controversial. In contrast, vulvar and penile cancer precursor lesions are known to be related to human papillomavirus or chronic inflammation and can be described using the vulvar intraepithelial neoplasia (VIN) classification system (VIN 1-3) or as differentiated vulvar intraepithelial neoplasia (dVIN), respectively. Oral and pharyngeal SCC precursor lesions are more etiologically diverse, and the spectrum of lesions may thus be wider. No international consensus exists regarding the histological types of precursor lesions or the significance of individual types. We therefore reviewed resection specimens and preceding biopsies of 155 patients with SCC of the oral cavity and pharynx (excluding tonsils) and identified five basic patterns of SCC-associated or precursor lesions: (1) pleomorphic (22/155), (2) basaloid (5/155), (3) differentiated (63/155), (4) mixed (42/155), and (5) verrucous (12/155). Keratinization was a common but variable feature in differentiated, mixed, and verrucous dysplasia. In 11/155 patients, no precursor lesion could be identified. Progression of isolated differentiated dysplasia (ranging from months to years) was documented in 13/155 (8 %) of patients. Our data suggest that full-thickness epithelial dysplasia of pleomorphic or basaloid type is present in <20 % of oral and pharyngeal SCC, and differentiated dysplasia is a frequent precursor or associated in situ lesion. Failure to recognize differentiated dysplasia results in the underdiagnosis of many patients at risk for invasive carcinoma. These results indicate a need to refine criteria to distinguish differentiated dysplasia from morphologically related lichenoid lesions.

Epigenetic dysregulation in laryngeal squamous cell carcinoma

Laryngeal carcinoma is a common head and neck cancer with poor prognosis. Patients with laryngeal carcinoma usually present late leading to the reduced treatment efficacy and high rate of recurrence. Despite the advance in the use of molecular markers for monitoring human cancers in the past decades, there are still no reliable markers for use to screen laryngeal carcinoma and follow the patients after treatment. Epigenetics emerged as an important field in understanding the biology of the human malignancies. Epigenetic alterations refer to the dysregulation of gene, which do not involve the alterations of the DNA sequence. Major epigenetic changes including methylation imbalance, histone modification, and small RNA dysregulation could play a role in the development of human malignancies. Global epigenetic change is now regarded as a molecular signature of cancer. The characteristics and behavior of a cancer could be predicted based on the specific epigenetic pattern. We here provide a review on the understanding of epigenetic dysregulation in laryngeal carcinoma. Further knowledge on the initiation and progression of laryngeal carcinoma at epigenetic level could promote the translation of the knowledge to clinical use.