Update on olfactory neuroblastoma

Olfactory neuroblastomas are uncommon malignancies that arise from olfactory receptor cells located high in the nasal cavity. Accurate diagnosis plays a crucial role in determining clinical results and guiding treatment decisions. Diagnosis can be a major challenge for pathologists, especially when dealing with tumours with poor differentiation. The discovery of several molecular and immunohistochemical markers would help to overcome classification difficulties. Due to the paucity of large-scale studies, standardisation of diagnosis, treatment and prediction of outcome remains a challenge. Surgical resection by endoscopic techniques with the addition of postoperative irradiation is the treatment of choice. In addition, it is advisable to consider elective neck irradiation to minimise the risk of nodal recurrence. Molecular characterisation will help not only to make more accurate diagnoses but also to identify specific molecular targets that can be used to develop personalised treatment options tailored to each patient. The present review aims to summarise the current state of knowledge on histopathological diagnosis, the molecular biology and management of this disease.

Molecularly defined sinonasal malignancies: an overview with focus on the current WHO classification and recently described provisional entities

Classification of tumors of the head and neck has evolved in recent decades including a widespread application of molecular testing in tumors of the sinonasal tract, salivary glands, and soft tissues with a predilection for the head and neck. The availability of new molecular techniques has allowed for the definition of multiple novel tumor types unique to head and neck sites. Moreover, an expanding spectrum of immunohistochemical markers specific to genetic alterations facilitates rapid identification of diagnostic molecular abnormalities. As such, it is currently possible for head and neck pathologists to benefit from a molecularly defined tumor classification while making diagnoses that are still based largely on histopathology and immunohistochemistry. This review covers the principal molecular alterations in sinonasal malignancies, such as alterations in DEK, AFF2, NUTM1, IDH1-2, and SWI/SNF genes in particular, that are important from a practical standpoint for diagnosis, prognosis, and prediction of response to treatment.

Clear Cell Neoplasms of Salivary Glands: A Diagnostic Challenge

This review focuses on the heterogenous group of clear cell neoplasms of salivary glands and attempts to identify major differential diagnostic features. Within the head and neck region, clear cells are found most commonly in salivary gland tumors, but may also be seen in tumors of squamous or odontogenic epithelial origin, primary or metastatic carcinomas, benign or malignant melanocytic lesions, or benign or malignant mesenchymal tumors. Clear cells occur fairly commonly among a wide variety of salivary gland neoplasms, but mostly they constitute only a minor component of the tumor cell population. Clear cells represent a major diagnostic feature in two salivary gland neoplasms, epithelial-myoepithelial carcinoma and hyalinizing clear cell carcinoma. In addition, salivary gland neoplasms composed predominantly of clear cells could also include clear cell variants of other salivary neoplasms, such as mucoepidermoid carcinoma and myoepithelial carcinoma, but their tumor type-specific histologic features may only be available in limited nonclear cell areas of the tumor. Diagnosing predominantly clear cell salivary gland tumors is difficult because the immunoprofiles and morphologic features may overlap and the same tumor entity may also have a wide range of other histologic presentations. Many salivary gland tumors are characterized by tumor type-specific genomic alterations, particularly gene fusions of the ETV6 gene in secretory carcinoma, the MYB and MYBL1 genes in adenoid cystic carcinoma, the MAML2 gene in mucoepidermoid carcinoma, the EWSR1 gene in hyalinizing clear cell carcinoma, and others. Thus, along with conventional histopathologic examination and immunoprofiling, molecular and genetic tests may be important in the diagnosis of salivary gland clear cell tumors by demonstrating genetic alterations specific to them.

Development of head and neck pathology in Europe

This review gives a brief history of the development of head and neck pathology in Europe from a humble beginning in the 1930s to the explosive activities the last 15 years. During the decades before the introduction of immunohistochemistry in the 1980s, head and neck pathology grew as a subspeciality in many European countries. In the late 1940s, the Institute of Laryngology and Otology with its own pathology laboratory was founded in London, and in 1964 the World Health Organization (WHO) International Reference Centre for the Histological Classification of Salivary Tumours was established at the Bland-Sutton Institute of Pathology, also in London. International collaboration, and very much so in Europe, led to the publication of the first WHO Classification of Salivary Gland Tumours in 1972. In the 1960s, a salivary gland register was organised in Hamburg and in Cologne the microlaryngoscopy was invented enabling microscopic endoscopic examination and rather shortly afterwards a carbon dioxide laser attached to the microscope became established and laryngeal lesions could be treated by laser vaporisation. During the last three decades, the use of immunohistochemistry supplemented with cytogenetic and refined molecular techniques has greatly facilitated the pathological diagnostics of head and neck lesions and has had a huge impact on research. Collaboration between different European centres has drastically increased partly due to establishment of scientific societies such as the Head and Neck Working Group (HNWG) within the European Society of Pathology and the International Head and Neck Scientific Group (IHNSG). A very large number of European pathologists have contributed to the 2nd, 3rd and 4th WHO books, and are involved in the upcoming 5th edition. Accredited educational meetings and courses are nowadays regularly arranged in Europe. Numerous textbooks on head and neck pathology have been written and edited by European pathologists. The increased collaboration has created larger series of tumours for research and new entities, mainly defined by their genetic abnormalities, are continuously emerging from Europe, particularly regarding salivary gland neoplasms and "undifferentiated" sinonasal tumours. These findings have led to a better and more precise classification and open the possibilities for new treatment strategies.

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.

Update on Neuroendocrine Carcinomas of the Larynx

OBJECTIVES

Laryngeal neuroendocrine carcinomas are heterogeneous neoplasms characterized by neuroendocrine differentiation. Their prognoses are dependent on tumor type, therefore different classifications have been developed. Moreover, other tumors have overlapping pathologic features posing a range of diagnostic possibilities.

METHODS

A review of the literature was performed to comprehensively understand the classification and diagnosis of these tumors.

RESULTS

We review the past and present classification systems, with emphasis to the latest 2017 World Health Organization Classification of Head and Neck Tumors. We highlight salient clinicopathologic features and discuss the presumptive etiologic role of human papilloma virus. We share a practical algorithmic approach to the diagnosis of suspected neuroendocrine neoplasms of the larynx including a novel marker for neuroendocrine differentiation, insulinoma-associated protein 1.

CONCLUSIONS

Accurate diagnosis and grading of laryngeal neuroendocrine carcinomas is critical for prognostication and therapeutic decision making. The use of an algorithm is instrumental in assuring the exclusion of mimickers.

An evidence-based analysis of the management of N0 neck in patients with cancer of the parotid gland

Introduction: Management of clinically negative neck (cN0) in patients with parotid gland cancer is controversial. Treatment options can include observation, elective neck dissection or elective radiotherapy. Areas covered: We addressed the treatment options for cN0 patients with parotid gland cancer. A literature review was undertaken to determine the optimal management of this group of patients. Expert opinion: Patients with parotid carcinoma and clinically negative neck have various options for their management. The analysis of tumor stage, histology and grade is essential to better define patients at risk for occult lymph node metastasis. These patients can be managed by surgery, radiotherapy or their combination, depending on the presence of risk factors, the moment at which such risk factors are detected, patient-related clinical conditions, medical provider expertise and institutional facilities.

Analysis of the Clinical Relevance of Histological Classification of Benign Epithelial Salivary Gland Tumours

INTRODUCTION

A vast increase in knowledge of numerous aspects of malignant salivary gland tumours has emerged during the last decade and, for several reasons, this has not been the case in benign epithelial salivary gland tumours. We have performed a literature review to investigate whether an accurate histological diagnosis of the 11 different types of benign epithelial salivary gland tumours is correlated to any differences in their clinical behaviour.

METHODS

A search was performed for histological classifications, recurrence rates and risks for malignant transformation, treatment modalities, and prognosis of these tumours. The search was performed primarily through PubMed, Google Scholar, and all versions of WHO classifications since 1972, as well as numerous textbooks on salivary gland tumours/head and neck/pathology/oncology. A large number of archival salivary tumours were also reviewed histologically.

RESULTS

Pleomorphic adenomas carry a considerable risk (5-15%) for malignant transformation but, albeit to a much lesser degree, so do basal cell adenomas and Warthin tumours, while the other eight types virtually never develop into malignancy. Pleomorphic adenoma has a rather high risk for recurrence while recurrence occurs only occasionally in sialadenoma papilliferum, oncocytoma, canalicular adenoma, myoepithelioma and the membranous type of basal cell adenoma. Papillomas, lymphadenoma, sebaceous adenoma, cystadenoma, basal cell adenoma (solid, trabecular and tubular subtypes) very rarely, if ever, recur.

CONCLUSIONS

A correct histopathological diagnosis of these tumours is necessary due to (1) preventing confusion with malignant salivary gland tumours; (2) only one (pleomorphic adenoma) has a considerable risk for malignant transformation, but all four histological types of basal cell adenoma can occasionally develop into malignancy, as does Warthin tumour; (3) sialadenoma papilliferum, oncocytoma, canalicular adenoma, myoepithelioma and Warthin tumour only occasionally recur; while (4) intraductal and inverted papilloma, lymphadenoma, sebaceous adenoma, cystadenoma, basal cell adenoma (apart from the membranous type) virtually never recur. No biomarker was found to be relevant for predicting recurrence or potential malignant development. Guidelines for appropriate treatment strategies are given.

Lymphomas of the head and neck region: an update

The field of haematopathology is rapidly evolving and for the non-specialized pathologist receiving a specimen with the possibility of a lymphoid malignancy may be a daunting experience. The coincidence of the publication, in 2017, of the WHO monographies on head and neck and haematopoietic and lymphoid tumours prompted us to write this review. Although not substantially different from lymphomas elsewhere, lymphomas presenting in this region pose some specific problems and these are central to the review. In addition, differences in subtype frequency and morphological variations within the same entity are discussed. The difficulty in diagnosis related to some specimens led us to briefly mention common subtypes of systemic lymphomas presenting in the head and neck region.

Polymorphous adenocarcinoma of the salivary glands: reappraisal and update

Although relatively rare, polymorphous adenocarcinoma (PAC) is likely the second most common malignancy of the minor salivary glands (MiSG). The diagnosis is mainly based on an incisional biopsy. The optimal treatment comprises wide surgical excision, often with adjuvant radiotherapy. In general, PAC has a good prognosis. Previously, PAC was referred to as polymorphous low-grade adenocarcinoma (PLGA), but the new WHO classification of salivary gland tumours has also included under the PAC subheading, the so-called cribriform adenocarcinoma of minor salivary glands (CAMSG). This approach raised controversy, predominantly because of possible differences in clinical behaviour. For example, PLGA (PAC, classical variant) only rarely metastasizes, whereas CAMSG  often shows metastases to the neck lymph nodes. Given the controversy, this review reappraises the definition, epidemiology, clinical presentation, diagnostic work-up, genetics, treatment modalities, and prognosis of PAC of the salivary glands with a particular focus on contrasting differences with CAMSG.

Effects of Formaldehyde on the Nasal Mucosa

To investigate health effects of long-term exposure to formaldehyde a cross-sectional field study was performed. Seventy formaldehyde-exposed workers were compared with a control group. A higher frequency of symptoms from upper and lower airways, headache, and dermal discomfort was found in the formaldehyde-exposed group. Further, formaldehyde-exposed workers showed disturbances of nasal physiologic conditions, such as slow nasal clearance, impairment of the sense of smell, more pronounced nasal mucosal swelling, and by spirometry lower forced vital capacity than expected was found. Nasal biopsies from the concha media showed more frequent histologic changes such as loss of cilia and metaplasia in the formaldehyde-exposed group. Histologic lesions did not correlate to current or cumulative exposure doses to formaldehyde. In an experimental study of Sprague-Dawley rats exposed to formaldehyde (12.7 mg/m3, 6 hours/day, 5 days/week for 24 months), one rat developed a squamous cell carcinoma in the nose and another nasal dysplasia and in seven other rats pronounced nasal metaplasia was seen in the nasal mucosa. In a control group of rats no significant histologic lesions were found.

Role of ancillary techniques in profiling unclassified laryngeal malignancies

Laryngeal biopsies, contrary to biopsies from many other sites of the body, very often contain minute amounts of tumour tissue that may consist of morphologically undifferentiated tumour only. In haematoxylin- and eosin-stained sections, there may be no indicative features of what specific tumour entity that is present. In the larynx, particularly small round cell neoplasms, primary or metastatic, often cause a diagnostic dilemma and where an incorrect diagnosis can induce substantial clinical consequences for the patient (e.g., primary neuroendocrine carcinomas vs metastatic variants, certain sarcomas). If sufficient/representative material has been obtained, the application of immunohistochemistry and/or molecular techniques should in virtually every case reveal the true nature of the malignancy. In cases with sparse amount of material, and therefore a limited number of sections to be cut, a careful and thoughtful stepwise approach is necessary to ascertain a reliable diagnosis, or at least guide the clinician to the most likely diagnoses. With today's advanced and widely available technology with an abundance of markers to discriminate different tumours, the use of the term "undifferentiated" should be largely unnecessary. In the exceptional, and indeed exceedingly rare cases, when a classification is not possible, even after repeat biopsy, we suggest that the laryngeal neoplasm is better termed "unclassified malignant neoplasm" rather than "undifferentiated malignant neoplasm".

How Phenotype Guides Management of the Most Common Malignant Salivary Neoplasms of the Larynx?

Salivary gland carcinomas of the larynx are uncommon. Adenoid cystic carcinoma is the most prevalent type of salivary gland carcinoma in this region, although other histologies such as mucoepidermoid carcinoma and adenocarcinomas have been reported. These tumors may present with advanced-stage due to nonspecific symptoms and their relatively slow-growing nature. The index of suspicion for a non-squamous cell carcinoma entity should be high when a submucosal mass is present. An accurate diagnosis is mandatory due to the impact each biologic entity has on treatment and outcome. Data concerning treatment and outcome are scarce, but primary surgery with utmost focus on free surgical margins is the treatment of choice. The role of adjuvant radiotherapy has not been well defined, although there is an agreement that it should be considered in advanced-stage or high-grade disease. This review considers only the most common malignant salivary neoplasms of the larynx with a focus on clinical management of these tumors.

NUT midline carcinoma of the larynx: an international series and review of the literature

AIMS

NUT midline carcinoma (NMC) is a rare undifferentiated and aggressive carcinoma that locates characteristically to the midline of the head and neck, and mediastinum. NMC is characterized by chromosomal rearrangements of the gene NUT, at 15q14. The BRD4 gene on 19q13 is the most common translocation partner forming a fusion oncogene, BRD4-NUT. By the end of 2014, the International NUT Midline Carcinoma Registry had 48 patients treated for NMC. Laryngeal NMC are exceedingly rare, and we report a case series of seven cases.

METHODS AND RESULTS

We searched for cases in files of different hospitals as well as a thorough search of the English language literature. The diagnosis of NMC is made by demonstration of NUT rearrangement either by immunohistochemistry, fluorescence in-situ hybridization (FISH) or reverse transcription-polymerase chain reaction (RT-PCR). We found three previously published cases, and in this series add four cases of our own.

CONCLUSIONS

NMC consists of monomorphic, often discohesive, cells with an epithelioid appearance and distinct nucleoli. The tumours typically show abrupt squamous differentiation. The mean age of the patients was 34 years, hence significantly lower than that for conventional laryngeal carcinoma. All tumours were located in the supraglottis and five patients died of the disease after 3, 7, 8, 9 and 11 months. Laryngeal NMC may be underdiagnosed, and an increased awareness among pathologists is warranted. NMC has characteristic morphological features, and positive immunostaining with the NUT antibody is diagnostic. Its aggressive behaviour demands a very intense treatment strategy and the need for its recognition is emphasized further by new promising treatment strategies.

Salivary gland hybrid tumour revisited: could they represent high-grade transformation in a low-grade neoplasm?

Salivary gland hybrid tumour, first described in 1996, is a very rare neoplasm for which exact morphological criteria have not been universally agreed upon. In contrast, the concept of high-grade transformation (HGT) in salivary neoplasms has been widely accepted during the last decade, and the number of reported cases is rapidly increasing. A review of the literature revealed 38 cases of hybrid tumour reported in 22 publications. During approximately the same time period, well over 100 cases of HGT in salivary neoplasms have been reported. There are important histological similarities between hybrid tumours and salivary tumours with HGT. In the latter, containing one tumour component of low-grade malignancy and the other of high grade, the two tumour components are not entirely separated and appear to originate in the same area. Virtually, all cases reported as hybrid tumour had no clear lines of demarcation between the two tumour types. We are inclined to suggest that most of the 38 cases of hybrid tumours described in the literature would today better be called tumour with HGT rather than hybrid tumour. The relative proportion of the two components may vary, and the high-grade component is sometimes very small, which emphasises the importance of very generous sampling of the surgical specimen. The molecular genetic mechanisms responsible for HGT, including what used to be called hybrid tumour, remain largely unknown. Abnormalities of a few genes (including p53, C-MYC, cyclin D1, HER-2/neu) have been documented. As insufficient data exist on gene abnormalities in these lesions, conclusions as to whether or not they have a common origin and which mechanisms are involved in transformation cannot be drawn. Due to the small number of cases reported, many of which lack follow-up details; indicators of prognosis of hybrid tumours are not available, but their behaviour seems to be similar to that of tumours with HGT, i.e. an accelerated aggressive course. HGT of salivary gland neoplasms greatly influences macroscopic and microscopic evaluation of the specimen but also, given the high incidence of metastases and morbidity, carries significant treatment implications.

High grade transformation of salivary gland acinic cell carcinoma with emphasis on histological diagnosis and clinical implications

Acinic cell carcinoma (ACC) is commonly thought of as a low grade malignant salivary neoplasm, and possibly has the best prognosis of all salivary malignancies with a 10-year survival of almost 90%. High grade transformation (HGT) in these tumours is a relatively rare event but is increasingly being reported. HGT (formerly referred to as dedifferentiation) in acinic cell carcinoma has shown to drastically reduce the survival rates and its recognition is imperative as more aggressive clinical management is needed. We report a case of parotid acinic cell carcinoma in a 82-year old woman where the fine needle aspirate suggested either pleomorphic adenoma or the possibility of carcinoma ex pleomorphic adenoma. Per-operatively it became clear that the facial nerve was involved and the tumour mass was debulked only. The histology showed an acinic cell carcinoma with foci of high grade differentiation (ACC-HGT). We describe the histology of HGT in ACC and the most common differential diagnoses. We emphasise the need of very generous sampling of the tumour, as to recognise any area of high grade transformation, some of which can be very small. A literature review of ACC-HGT as well as HGT in other salivary gland neoplasms is presented. HGT of ACC greatly thus influences the macroscopical and microscopical evaluation of the specimen but also, given the high incidence of metastases and morbidity, carries significant treatment implications.

Cervical lymph node metastasis in adenoid cystic carcinoma of oral cavity and oropharynx: A collective international review

The purpose of this study was to suggest general guidelines in the management of the N0 neck of oral cavity and oropharyngeal adenoid cystic carcinoma (AdCC) in order to improve the survival of these patients and/or reduce the risk of neck recurrences. The incidence of cervical node metastasis at diagnosis of head and neck AdCC is variable, and ranges between 3% and 16%. Metastasis to the cervical lymph nodes of intraoral and oropharyngeal AdCC varies from 2% to 43%, with the lower rates pertaining to palatal AdCC and the higher rates to base of the tongue. Neck node recurrence may happen after treatment in 0-14% of AdCC, is highly dependent on the extent of the treatment and is very rare in patients who have been treated with therapeutic or elective neck dissections, or elective neck irradiation. Lymph node involvement with or without extracapsular extension in AdCC has been shown in most reports to be independently associated with decreased overall and cause-specific survival, probably because lymph node involvement is a risk factor for subsequent distant metastasis. The overall rate of occult neck metastasis in patients with head and neck AdCC ranges from 15% to 44%, but occult neck metastasis from oral cavity and/or oropharynx seems to occur more frequently than from other locations, such as the sinonasal tract and major salivary glands. Nevertheless, the benefit of elective neck dissection (END) in AdCC is not comparable to that of squamous cell carcinoma, because the main cause of failure is not related to neck or local recurrence, but rather, to distant failure. Therefore, END should be considered in patients with a cN0 neck with AdCC in some high risk oral and oropharyngeal locations when postoperative RT is not planned, or the rare AdCC-high grade transformation.

Cervical Lymph Node Metastasis in High-Grade Transformation of Head and Neck Adenoid Cystic Carcinoma: A Collective International Review

Adenoid cystic carcinoma (AdCC) is among the most common malignant tumors of the salivary glands. It is characterized by a prolonged clinical course, with frequent local recurrences, late onset of metastases and fatal outcome. High-grade transformation (HGT) is an uncommon phenomenon among salivary carcinomas and is associated with increased tumor aggressiveness. In AdCC with high-grade transformation (AdCC–HGT), the clinical course deviates from the natural history of AdCC. It tends to be accelerated, with a high propensity for lymph node metastasis. In order to shed light on this rare event and, in particular, on treatment implications, we undertook this review: searching for all published cases of AdCC-HGT. We conclude that it is mandatory to perform elective neck dissection in patients with AdCC-HGT, due to the high risk of lymph node metastases associated with transformation.

Salivary acinic cell carcinoma: reappraisal and update

Epidemiologic and clinicopathologic features, therapeutic strategies, and prognosis for acinic cell carcinoma of the major and minor salivary glands are critically reviewed. We explore histopathologic, histochemical, electron microscopic and immunohistochemical aspects and discuss histologic grading, histogenesis, animal models, and genetic events. In the context of possible diagnostic difficulties, the relationship to mammary analog secretory carcinoma is probed and a classification is suggested. Areas of controversy or uncertainty, which may benefit from further investigations, are also highlighted.

Neuroendocrine neoplasms of the sinonasal region

Neuroendocrine neoplasms of the sinonasal region, which are relatively uncommon but clinically very important, are reviewed here in the light of current knowledge. Using a definition for neuroendocrine based on phenotypic, histologic, immunohistochemical, and electron microscopic features rather than histogenetic criteria, sinonasal neuroendocrine carcinomas are examined with a particular emphasis on the small-cell and large-cell subtypes. This is followed by revisiting olfactory neuroblastoma because it is also a tumor that shows a neuroendocrine phenotype. Kadish clinical and Hyams histologic grading systems as prognosticators of olfactory neuroblastoma are also considered in detail. Finally, controversies regarding sinonasal undifferentiated carcinoma as a neuroendocrine tumor are discussed and a possible relationship with high-grade olfactory neuroblastoma is explored. Genetic events and current management of these tumors are also outlined. © 2015 Wiley Periodicals, Inc. Head Neck 38: E2259-E2266, 2016.

Rhabdomyoblastic Differentiation in Head and Neck Malignancies Other Than Rhabdomyosarcoma

Rhabdomyosarcoma is a relatively common soft tissue sarcoma that frequently affects children and adolescents and may involve the head and neck. Rhabdomyosarcoma is defined by skeletal muscle differentiation which can be suggested by routine histology and confirmed by immunohistochemistry for the skeletal muscle-specific markers myogenin or myoD1. At the same time, it must be remembered that when it comes to head and neck malignancies, skeletal muscle differentiation is not limited to rhabdomyosarcoma. A lack of awareness of this phenomenon could lead to misdiagnosis and, subsequently, inappropriate therapeutic interventions. This review focuses on malignant neoplasms of the head and neck other than rhabdomyosarcoma that may exhibit rhabdomyoblastic differentiation, with an emphasis on strategies to resolve the diagnostic dilemmas these tumors may present. Axiomatically, no primary central nervous system tumors will be discussed.

European position paper on endoscopic management of tumours of the nose, paranasal sinuses and skull base

Tumours affecting the nose, paranasal sinuses and adjacent skull base are fortunately rare. However, they pose significant problems of management due their late presentation and juxtaposition to important anatomical structures such eye and brain. The increasing application of endonasal endoscopic techniques to their excision offers potentially similar scales of resection but with reduced morbidity. The present document is intended to be a state-of-the art review for any specialist with an interest in this area 1. to update their knowledge of neoplasia affecting the nose, paranasal sinuses and adjacent skull base; 2. to provide an evidence-based review of the diagnostic methods; 3. to provide an evidence-based review of endoscopic techniques in the context of other available treatments; 4. to propose algorithms for the management of the disease; 5. to propose guidance for outcome measurements for research and encourage prospective collection of data. The importance of a multidisciplinary approach, adherence to oncologic principles with intent to cure and need for long-term follow-up is emphasised.

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

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.

Criteria for grading in the Ljubljana classification of epithelial hyperplastic laryngeal lesions. A study by members of the Working Group on Epithelial Hyperplastic Laryngeal Lesions of the European Society of Pathology

AIMS

To validate histological criteria for the grading of epithelial hyperplastic laryngeal lesions (EHHL) (dysplastic laryngeal lesions), we used a system that had been devised and tested in Ljubljana, Slovenia over many years and was felt to be more appropriate to laryngeal pathology than is the commonly-used model of intraepithelial neoplasia in the cervix.

METHODS AND RESULTS

Vocal cord biopsies of 45 patients with a broad spectrum of EHLL were reviewed. Detailed histological criteria were formulated for each of the four grades of EHLL in the Ljubljana classification, comprising simple hyperplasia (benign spinous layer augmentation), abnormal hyperplasia (benign basal and parabasal layer augmentation), atypical hyperplasia (risky for malignancy) and carcinoma in situ (actually malignant, but without invasion).

CONCLUSIONS

Using these criteria a high degree of concordance of histological diagnoses of grading levels for the Ljubljana classification was achieved between the pathologists of the Working Group. The system was found to be more precise for routine diagnostic work than the others in vogue. The different grades of the Ljubljana classification correspond to significantly different levels yielded in each grade by the semiobjective methods of quantitative morphometry and immunohistochemistry.

Spindle cell carcinoma of the larynx

The clinicopathological features of 14 laryngeal neoplasms consisting of spindle-shaped cells are presented. Light microscopy showed a variety of morphological patterns from that of pleomorphic sarcoma and fibrosarcoma to more loose vascular patterns. Immunohistochemistry revealed that the spindle-shaped cells had a positive keratin immunoreactivity in 8 of 14 cases, and also that some cases had a dual expression of keratin and vimentin filaments. Electron microscopy showed that spindle-shaped cells had epithelial ultrastructures. The results support the hypothesis that the spindle cell carcinomas are true carcinomas with mesenchymal metaplasia and that the spindle-shaped cells are part of the neoplasm and not benign, reactive fibroblasts. These lesions occurred mainly on the true vocal cords in elderly patients. The neoplasms were nearly all polypoid, and many also ulcerated. There is no significant difference in clinical behaviour between laryngeal spindle cell carcinomas and ordinary squamous cell carcinomas of the larynx, and the same treatment policy is therefore advocated. Being polypoid and therefore able to be surgically removed with relative ease, they may even present a more favourable clinical course.

Histological changes in the nasal mucosa in rats after long-term exposure to formaldehyde and wood dust

Wood dust is a well known nasal carcinogen in man, as formaldehyde is in rats. In certain occupational environments, combined exposure to wood dust and formaldehyde is common. Little is known about the effects of this combination. A pilot study was performed on four groups of Sprague-Dawley rats: one exposed to wood dust (25 mg/m3), another to formaldehyde (12.4 ppm) and a third to both wood dust and formaldehyde; the fourth group served a control group. After 104 weeks of exposure the nose and lungs were examined histologically. One well differentiated squamous cell carcinoma was found in the formaldehyde group. Squamous cell metaplasia was found significantly more often among the formaldehyde-exposed rats. Squamous cell metaplasia with dysplasia was most frequently observed, however, in the group exposed to both formaldehyde and wood dust. There were also significantly more rats with pulmonary emphysema in the groups exposed to wood dust than in the other groups.

Histological changes in the nasal mucosa in persons occupationally exposed to formaldehyde alone and in combination with wood dust

In the nasal mucosa of rodents, both formaldehyde and wood dust have proved to be carcinogenic. Wood dust is also a well-known nasal carcinogen in man. The effects of long-term exposure of humans to formaldehyde, however, are more obscure. In this investigation two groups of workers with well-defined exposure to formaldehyde and to formaldehyde and wood dust, respectively, were compared with a control group regarding histological changes in nasal specimens from the middle turbinate. Significant changes were found in the formaldehyde group but not in the group exposed to both formaldehyde and wood dust. No correlation was found between histological changes and duration of exposure, doses of exposure or smoking habits.

Occupational exposure to formaldehyde and histopathological changes in the nasal mucosa

To study the cytotoxic effect of formaldehyde on the human nasal mucosa 75 men with occupational exposure to formaldehyde or to formaldehyde and wood dust, were examined, looking particularly at early signs of irritative effects and histopathological changes in the nasal mucosa. All men underwent a medical examination and a nasal biopsy specimen was examined by a pathologist and graded from 0-8 according to the morphological changes. A high frequency of nasal symptoms, mostly a running nose and crusting, was related to exposure to formaldehyde. Only three men had a normal mucosa; the remainder had loss of cilia and goblet cell hyperplasia (11%) and squamous metaplasia (78%); in six cases (8%) there was a mild dysplasia. The histological grading showed a significantly higher score when compared with unexposed contents (2.9 v 1.8). There was no dose response relation, no malignancies, and no difference in the histological score between those exposed to formaldehyde or to formaldehyde and wood dust.

Evaluation of lip salivary gland biopsy in 21 patients with primary Sjögren's syndrome

Lip salivary gland biopsy was performed in 21 (20 female) patients, age 26 to 74 years, with primary Sjögren's syndrome. The procedure helped identify a patient group with many autoimmune phenomena, including hypergammaglobulinemia, autoantibodies, autoimmune thyroiditis, vasculitis, and immunocytoma. A marked association with the HLA-DR3 antigen was noted. It is concluded that lip salivary gland biopsy is a simple and safe procedure that makes possible the identification among non-RA patients with sicca symptoms those who have autoimmune disturbance. This patient group deserves close medical supervision in order to detect autoimmune disease that requires treatment, such as autoimmune thyroiditis and lymphoma.

Occupational formaldehyde exposure and the nasal mucosa

This study was undertaken to evaluate the possible cytotoxic effect of formaldehyde on the nasal mucosa in man. 38 men with an average age of 38 years and average exposure time of 10.5 years were studied. They were exposed to formaldehyde when processing laminae. All men passed a medical examination and a nasal biopsy. The histological findings were scored, 0-8, according to a system proposed by Torjussen. The findings were compared with a non-exposed reference group of 25 men (mean age 35 years). 35% of the exposed were smokers compared to 48% of the nonexposed. The average histological score was 2.8 for the exposed versus 1.8 for the non-exposed (p less than 0.05, Wilcoxon). The more common findings in the exposed were loss of cilia, goblet cell hyperplasia and squamous metaplasia. In four cases (11%) there was a mild dysplasia. Smoking had a slight modifying effect on the histological picture. The results indicate that the suspected precancerous findings in animal studies after exposure to formaldehyde might be present in workers exposed to formaldehyde at relatively low levels.

Video time-lapse microscopy of human laryngeal carcinomas in vitro

Twelve human laryngeal carcinomas and 14 normal vocal cord epithelia were studied in vitro by the method of tissue culture incorporating video time-lapse microscopy. Different events were photographed by taking 'stills' from the television monitor during play-back. Outgrowths from both tumour and normal explants formed only as monolayers. Mitoses were mainly found to be localized approximately mid-way between explant and the edge of the outgrowth. Some cells were seen to become suddenly active producing oscillating blebs and sometimes they detached themselves from the monolayer culture and changed appearance. This was more prevalent in the tumour cultures. In both tumour and normal cell cultures lymphocytes were observed and their normal chemokinetic movement was changed into a rapid chemotactic attraction by the presence of a mitotic epithelial cell. These lymphocytes appear to represent T-suppressor cells. The present study has shown that primary tissue culture can be a valuable tool in the study of laryngeal carcinoma. The interaction between mitotic tumour cells and lymphocytes may represent a transformation of T-lymphocytes into LAK cells.

Malignant mixed tumour. A salivary gland tumour showing both carcinomatous and sarcomatous features

Two malignant mixed tumours, in which both carcinomatous and sarcomatous features were present, are described. They arose in the palate in patients who had undergone surgery and irradiation for a pleomorphic adenoma at the same site 30 and 36 years previously. The histological differential diagnoses of recurrent benign pleomorphic adenoma, pleomorphic adenoma resembling mesenchymal tumour, and carcinoma in (ex) pleomorphic adenoma are discussed. On the basis of their positive reaction for keratin with specific monoclonal antibodies it is suggested that the myoepithelial cells are of epithelial origin. Immunohistochemical studies together with the histological appearance of the neoplasms indicate that the carcinomatous as well as the sarcomatous elements were derived from modified myoepithelial tumour cells. Irradiation may have been responsible for inducing a true malignant mixed tumour as distinct from the more common malignancy which may arise in pleomorphic adenoma, this being a simple carcinoma.

Nasal cuboidal metaplasia with dysplasia. Precursor to adenocarcinoma in wood-dust-exposed workers?

The histological study of the non-tumours nasal mucosa in 22 wood-workers with ethmoidal adenocarcinoma was carried out and special attention was paid to the presence of cuboidal metaplasia with or without dysplasia. The workers had been exposed to wood dust for an average of 38 years (range 18 to 55 years). In 19 cases cuboidal metaplasia was found and 16 of these also had dysplasia. In 10 cases there was a transitional zone with dysplastic cuboidal epithelium in continuity with the tumour. In 5 cases there was squamous metaplasia. The results indicate cuboidal metaplasia with dysplasia being a possible precursor to nasal adenocarcinoma in workers exposed to wood dust, similar to the findings of squamous metaplasia and squamous cell carcinoma in nickel workers.

Adenocarcinoma of the ethmoid sinuses. A review of 28 cases with special reference to wood dust exposure

Adenocarcinoma makes up only a small percent of all nasal and paranasal sinus carcinomas, and is most often found in the ethmoid sinuses. Adenocarcinoma of the ethmoid sinuses is known to be associated with exposure to wood dust. Twenty-eight patients with ethmoid adenocarcinomas were collected, mainly during the last decade from a region with approximately 900,000 inhabitants and with a large amount of furniture industries. There were 4 women and 24 men in the study. Twenty of the men were exposed to dust from hardwood for 20 to 55 years (mean, 40 years) which is in accord with other reports and supports data on the increased risk for workers of developing adenocarcinoma of the ethmoid sinuses when exposed to dust from hardwood. Radiologic diagnosis is necessary to delineate the extent of these tumours, and computerized tomography (CT) especially furnishes important information. Most patients received preoperative radiotherapy followed by surgery, 50% of them survived 5 years, which is in accord with other reports.

Cholesterol granuloma of the maxillary and frontal sinuses

5 cases of cholesterol granuloma are described, 3 within the maxillary sinuses and 2 within the frontal sinuses. The lesions arise from the mucosa and can be recognized on plain films and tomograms of the sinus as opacity, sometimes resembling a mucocele. Radical operation seems to give absolute cure without any recurrence. The pathogenesis is hemorrhage and/or filtration. The closed cavities of the paranasal sinuses provide favorable conditions for cholesterol to become dissociated from the lipoprotein complex and to precipitate and to give rise to a granulomatous reaction.

Nasal symptoms and histopathology in a group of spray-painters

Industrial workers more and more frequently seek medical advice for nasal and sinus symptoms that they attribute to occupational exposure. The present study comprised 10 paint-sprayers exposed to solvents (primarily toluene and isobutylacetate) and dust. The working environment was checked by an industrial hygienist and a careful clinical examination including biopsies from the nasal mucosa was carried out. The results revealed prominent nasal symptoms in 3 patients and 4 suffered from cough. The histological examination showed in no case a normal nasal mucosa. The histological grading showed a significantly higher score in the exposed group compared to a matched control group. However, no conclusive connection between the duration of exposure and the clinical symptoms and morphological changes was possible to make, which will necessitate an extended study to evaluate the exact importance of the duration of exposure. The study indicates the possibilities of an early presymptomatic detection of nasal mucosal disturbances and arises the question whether the existing TLVs are adequate in preventing damage to the nasal mucosa and adherent clinical symptoms.

Scanning electron microscopy of vocal cord hyperplasia, keratosis, papillomatosis, dysplasia and carcinoma

The vocal cord fine surface structure was examined by scanning electron microscopy (SEM), and the observations related to the light-microscopical (LM) findings after embedding and cutting. The SEM micrographs were assessed using a rating system based on 7 parameters. The proportion of "normal" and "abnormal" SEM areas varied within the respective histologic groups. There was, however, a significant difference between the SEM ratings in the group with hyperplasia-keratosis, with or without mild dysplasia, compared to the groups with severe dysplasia-carcinoma in situ and invasive squamous cell carcinoma. In the small number of cases with moderate dysplasia and juvenile laryngeal papilloma, the SEM ratings displayed pronounced disparity.

The role of smear cytology in laryngeal diagnosis

There may be great difficulty especially in diffuse lesions, in obtaining representative laryngeal biopsy specimens. Therefore the reliability of laryngeal smear cytology was evaluated in comparison with the histologic diagnosis. The cytologic specimens were taken during 520 microlaryngoscopic examinations (direct technique). The sensitivity of the direct cytologic method in the detection of moderate dysplasia, severe dysplasia-carcinoma in situ, and invasive carcinoma was 45% (17/38), 83% (59/71), and 93% (137/147), respectively. A false negative cytologic reading was more frequent after radiotherapy. The specificity of the direct cytologic technique in the detection of histologically "benign" lesions was 80% (210/264). In 23 patients cytologic smears were obtained at mirror laryngoscopy (indirect technique). Both the direct and indirect cytologic tests are easy to perform, quick, and may be of diagnostic value in laryngeal diagnosis, especially in screening examinations. However, cytology cannot supersede the histological examination of biopsy specimens.

Bilateral acute retinal necrosis

Four patients who experienced the sudden onset of anterior uveitis with large keratic precipitates and dense vitreous opacities developed confluent yellow-white swellings and exudates in the peripheral retina and sheathing and obliteration of retinal arteries. After absorption of the exudates, atrophic patches in the peripheral retina and a funnel-shaped retinal detachment with many tears appeared. Angiograms showed retinal edema, fluorescein leakage from the choroid in the affected areas, and perivasculitis of the retinal arteries. Although treatment seemed unable to alter the course of the disease, in one case the retina reattachment after vitrectomy and filling of the vitreous space with silicone oil. Histopathologic studies disclosed extensive atrophy and degeneration of the outer retinal layers and pigment epithelium and occlusion of the retinal vessels. An infection may trigger the uveitis, leading to an autoimmune sensitization against rods and cones that causes severe local immune-complex disease and retinal vasculitis.

Hyperplasia, keratosis, dysplasia and carcinoma in situ of the vocal cords--a follow-up study

Comparison of reported series of laryngeal lesions is complicated by the inconsistency in the terminology. The classification of these lesions should logically be based on the degrees of dysplasia, as this has a bearing on the prognosis. The material for this study consisted of 193 patients with hyperplasia and/or keratosis, with or without mild dysplasia (Group I), moderate dysplasia (Group II), and severe dysplasia and carcinoma in situ (Group III). They were treated over a 14-year period (1966-1979) at Linköping University Hospital. Of the 98 patients in Group I available for follow-up, 23 had repeat excisions. Moderate dysplasia developed in 3 patients, severe dysplasia in 2, and invasive carcinoma in another 2 within 3 and 3.5 years; they both underwent laryngectomy. Among the 24 patients in Group II available for follow-up, severe dysplasia developed in 3 and invasive carcinoma in 3 up to 13 years after the initial diagnosis, all but one (with severe dysplasia) received a full course of radiotherapy, on one case total laryngectomy was subsequently performed for recurrent carcinoma. Of the 39 patients with severe dysplasia and carcinoma in situ 16 were given primary radiotherapy; 4 of these developed invasive carcinoma; 3 of them underwent total laryngectomy and one partial laryngectomy. Excision or stripping of the vocal cords was the primary treatment in 23 cases; 5 of these developed invasive carcinoma; 2 of them underwent total laryngectomy. Diffuse lesions and well differentiated forms of severe dysplasia caused most problems and had the highest incidence of invasive carcinoma irrespective of the form of treatment. Patients with hyperplasia, keratosis, dysplasia and carcinoma in situ should be carefully followed up, as invasive carcinoma may develop many years after the initial diagnosis.

HISTOSCAN: computer program for cytophotometry in tissue sections and its application in the evaluation of nuclear atypia

The grading of nuclear atypia has a great and well recognized value when predicting the malignancy of neoplastic processes. Although the basic criteria for the grading are generally agreed upon, in the individual case, the final judgement is to some extent still a matter of subjectivity, which naturally impairs reproducibility. The present paper describes a method for quantification of variability of nuclear size and Feulgen-stainability. By plotting the mean optical density against the area value in a scatter-diagram, a cluster is obtained, the size of which reflects the degree of nuclear atypia. The measurements are performed in tissue sections using stage scanning cytophotometry. A computer program--HISTOSCAN--has been developed which enables measurements in highly cellular tissues. The system is also insensitive to the influence of light scattering, a factor of importance when measuring in tissue sections. The performance of the program is tested in both imprints and tissue sections.