Nina Gale

The Ljubljana classification: a practical strategy for the diagnosis of laryngeal precancerous lesions.

Summary: There is no internationally accepted classification of epithelial hyperplastic laryngeal lesions (EHLL). The majority of current classifications follow criteria similar to those commonly used for cervical epithelial lesions. However, the different etiology of laryngeal cancer and its particular clinical and histologic features necessitate a grading system more appropriate to this region. The Ljubljana classification of EHLL was devised in 1971 to cater to this requirement. Detailed criteria for histologic grading in this classification were formulated by a working group on EHLL of the European Society of Pathology in 1999. The system recognizes four grades: simple and abnormal hyperplasia are benign categories; atypical hyperplasia (“risky” epithelium) is potentially malignant, and carcinoma in situ actually malignant. The main features by which the proposed grading system differs from other classifications are: 1. the distinction between benign and potentially malignant lesions: 2. the positive separation of carcinoma in situ from atypical hyperplasia; 3. the lack of prognostic significance for any surface keratin layer. The eventual outcome of EHLL patients so graded justifies the proposal for separating the lesions into a benign group, showing malignant transformation in only 0.9% of cases, from a potentially malignant group showing malignant transformation in 11% of cases. For diagnostically difficult cases, supplementary techniques such as those using morphometry, immunohistochemical and molecular biology are advised to improve the accuracy of diagnosis and predictions of their biological behavior.

Current review on squamous intraepithelial lesions of the larynx

Squamous intraepithelial lesions (SILs) of the larynx, clinically usually defined as leukoplakia and chronic laryngitis, have remained the main controversial topic in laryngeal pathology for decades as regards classification, histological diagnosis and treatment. SILs are caused by smoking and alcohol abuse. There is also mounting evidence that gastroesophageal reflux is a potential aetiological factor. Human papillomavirus infection seems to play little if any role in laryngeal carcinogenesis.

Expression of Ki-67 antigen and proliferative cell nuclear antigen in benign and malignant epithelial lesions of the larynx

In an attempt to analyse the proliferative activity in benign and malignant laryngeal epithelial lesions, and to determine the relationship to their histologic grade, we studied the expression of proliferative cell nuclear antigen (PCNA) and Ki-67 antigen on 20 squamous carcinomas, and on 30 biopsies of epithelial hyperplasia categorized according to the Kambic-Lenart classification into simple, abnormal, and atypical hyperplasias. In simple hyperplasia, both antibodies stained the nuclei of the occasional cells in the basal layer. In abnormal hyperplasia (mild dyplasia), positive cells occupied up to a third, and in atypical hyperplasia (moderate and severe dysplasia) they occupied from two-thirds to the entire epithelial thickness. In squamous carcinoma, we have found a statistically significant correlation between its grade and the percentage of Ki-67-(p < 0.01) and PCNA-(p < 0.00001) positive cells. Our results suggest that the proliferative fraction progressively increases with the degree of epithelial hyperplasia and the grade of carcinoma. We conclude that the patterns of immunoreactivity to PCNA and Ki-67 antigen correspond to the histologic grade of both benign and malignant epithelial lesions of the larynx. This method should be regarded as a useful adjunct to traditional histological techniques allowing more objective grading of benign and malignant epithelial lesions.

Cadherin–catenin complex and transcription factor Snail-1 in spindle cell carcinoma of the head and neck

Spindle cell carcinoma (SpCC) is a biphasic tumor composed of squamous cell carcinoma (SCC) and a malignant spindle cell component. There is mounting evidence that SpCC is a monoclonal neoplasm originating from a stem cell giving rise to both components. We tested the hypothesis that spindle cell phenotype might be related to the cadherin–catenin complex, which forms adherens junctions between cells. We analyzed the immunohistochemical expression of E- and N-cadherin, α-, β- and γ-catenin, and Snail-1, a transcription repressor of E-cadherin, in 30 cases of SpCC, and 30 cases of SCC of the head and neck. In SpCC, cadherin and catenin expression was similar in the SCC component, whereas in the spindle cell component, loss of E-cadherin and neo-expression of N-cadherin was found in 19 cases, loss of cadherins in seven, and their co-expression in four cases. Catenin expression were altered in 18 SpCCs. Snail-1 was found in 19 SpCC cases. In SCC, E-cadherin and catenins were expressed in all cases, and N-cadherin focally in five cases. Snail-1 was observed in the stroma. To summarize, in SpCC, there is an altered expression of the cadherin–catenin complex, associated with morphological transition from epithelial to spindle cell phenotype. These features are reminiscent of epithelial–mesenchymal transition (EMT). Our study thus indicates that EMT might play an important role in the pathogenesis of SpCC. This conclusion is further supported by our finding of Snail-1 expression, a potent inducer of EMT, in more than half SpCC cases.

Down-regulation of microRNAs of the miR-200 family and miR-205, and an altered expression of classic and desmosomal cadherins in spindle cell carcinoma of the head and neck--hallmark of epithelial-mesenchymal transition.

MicroRNAs are small, noncoding RNAs that regulate gene expression by posttranscriptional regulation of target genes. miR-200 family and miR-205 have been shown experimentally to regulate epithelial-mesenchymal transition. As epithelial-mesenchymal transition is the postulated pathogenetic mechanism in spindle cell carcinoma, we analyzed the expression of these microRNAs in spindle cell carcinoma of the head and neck in comparison to conventional squamous cell carcinoma of similar location and stage. We also analyzed the expression of classic and desmosomal cadherins, which are believed to be important targets during epithelial-mesenchymal transition. Forty-five cases of spindle cell carcinoma and 45 cases of squamous cell carcinoma of the head and neck were analyzed using real-time polymerase chain reaction for microRNAs, and immunohistochemistry for classic cadherins (E- and N-cadherins) and desmosomal cadherins. We found a significant down-regulation of the miR-200 family and miR-205, loss of desmosomal cadherins, and an altered expression of classic cadherins in spindle cell carcinoma in comparison to squamous cell carcinoma. Down-regulation of the miR-200 family and miR-205 strongly supports the postulated role of epithelial-mesenchymal transition in spindle cell carcinoma. These microRNAs act on transcription repressors that were also up-regulated in our cases of spindle cell carcinoma, both on mRNA and on protein levels. The result is not only an altered expression of classic cadherins in adherens junctions but also a complete loss of desmosomal cadherins.

Detection of Human Papillomaviruses in Tissue Specimens

Summary During the past decade, molecular methods based on the detection of viral DNA have become a key tool for the detection of human papillomaviruses (HPVs) in tissue. The methods can be divided into two groups: those in which tissue destruction is unavoidable for the detection of HPV DNA, and those in which the detection of viral DNA is performed in a way that allows tissue morphology preservation. Polymerase chain reaction is currently the most sensitive method for HPV detection and an excellent research tool. However, because of frequent contamination problems and lack of standardization, it is not readily applicable to diagnostic laboratories. The recent improvements in in situ hybridization have made it possible for this method to become the most appropriate method for routine detection of HPVs in tissue. At present, however, the use of at least two independent HPV DNA detection methods is indispensable for accurate determination of HPVs.

Inflammatory myofibroblastic tumour of paranasal sinuses with fatal outcome: reactive lesion or tumour?

Inflammatory myofibroblastic tumours (IMTs) are clinicopathologically distinctive but biologically controversial entities, which have been described in the lungs, abdomen, retroperitoneum, and extremities, but rarely affect the head and neck region. IMT usually follows a benign clinical course after radical excision, but invasive, locally recurrent, and metastatic forms of abdominal and mediastinal IMT have also been described. This report describes a case of IMT of the paranasal sinuses with a fatal outcome. A 22 year old woman was admitted to hospital as a result of epistaxis. Computed tomography scan and magnetic resonance imaging showed an expansive process in the paranasal sinuses, extending into the nasal cavity, orbita, and endocranium. The tumour progressed despite several surgical procedures. Radiotherapy, corticosteroids, and chemotherapy were unsuccessful, and the patient died four years after diagnosis, as a result of extensive intracranial spread of the tumour. This is the first known case of an IMT of the head and neck region with a fatal outcome. It shows that the aggressive behaviour of IMTs is not limited to abdominal and mediastinal locations, and supports recent observations that at least a subset of IMTs represents true neoplasia rather than reactive myofibroblastic proliferation.

Proliferation of Myofibroblasts in the Stroma of Epithelial Hyperplastic Lesions and Squamous Carcinoma of the Larynx

Objectives: The immunohistochemical phenotype, distribution and significance of proliferation of myofibroblasts in laryngeal epithelial hyperplastic lesions (EHL) and squamous carcinoma (SC) were analyzed. Methods: Samples of 42 resected larynxes and 40 laryngeal biopsies of EHL and SC were included. Immunohistochemistry was performed using antibodies against vimentin, α-smooth muscle actin (SMA), desmin and leukocyte common antigen. Results: Myofibroblasts were vimentin- and SMA-positive, and were found exclusively in SC, indicating that invasion beyond the basement membrane is necessary to evoke a myofibroblastic stromal reaction. We observed two patterns of stromal reaction in SC: one was characterized by a marked proliferation of myofibroblasts and desmoplasia, with scarce lymphocytic infiltration; this pattern tended to be associated with well- or moderately differentiated SC. The other was characterized by few myofibroblasts, weak desmoplasia, and dense lymphocytic infiltration; the latter pattern tended to be associated with moderately or poorly differentiated SC. The degree of myofibroblast proliferation was inversely related to the density of lymphocytic infiltration. Antibodies against SMA also stained stromal blood vessels, demonstrating a gradual increase of vessel density as the grade of EHL increased. Conclusions: Immunohistochemical analysis of myofibroblasts provides useful information on the phenotypic characteristics of the stroma in laryngeal EHL and SC, and can serve as an additional marker of invasion.

Laryngeal papillomatosis: molecular, histopathological, and clinical evaluation

Molecular, histopathological, and clinical studies were carried out on a series of 79 laryngeal papillomas (LP) from 36 patients in order to investigate the hypothesis that juvenile and adult LP may represent a biological entity causally related to Human papilloma virus (HPV) infection. Using in situ hybridization with biotin-labelled probes and polymerase chain reaction, we detected human papilloma virus (HPV) 6/11 in 28 of 29 juvenile LP, in 26 of 30 adult multiple, and in 17 of 20 adult solitary LP. None of LP was found to harbour HPV types 16, 18, 31, 33, and 51. There were no clear-cut histological differences between juvenile and adult LP, the presence of koilocytosis was equally observed in both, and there was no prevalent type of epithelial hyperplasia in either form, except that all three cases of atypical hyperplasias (precancerous lesions) were found among adult patients. During a 14 year follow-up, no carcinomatous transformation of LP was observed. All juvenile LP in our study had frequent recurrences of the disease, however, numerous surgical procedures were also required in 16 of 27 adult patients. Our study supports Lindebergs hypothesis of a similar pathogenesis for all forms of LP caused by the HPV types 6/11.

Pseudovascular adenoid squamous-cell carcinoma of the oral cavity—a report of two cases

Informed consent was obtained for the publication of the patients’ details in this report. Two cases of pseudovascular adenoid squamous-cell carcinoma (SCC) in the oral cavity are described, which were characterised by acantholysis of the tumour cells, with formation of anastomosing spaces and channels mimicking an angiosarcoma. Both tumours contained foci of SCC suggesting the correct diagnosis: in one patient conventional SCC, and in the other, a spindle-cell carcinoma. The pathogenesis of pseudovascular adenoid SCC is unknown. Our cases were characterised by loss of immunohistochemical expression of E-cadherin, one of the major adhesion molecules of epithelial cells. Pseudovascular adenoid SCC is suggested to be pathogenetically related to the loss of E-cadherin expression, leading to the loss of tumour cell–cell adhesion.