Paul M. Speight - Shear's Cysts of the Oral and Maxillofacial Regions

As scientific inquiry has exploded in recent years and the publication interval of the WHO series of classification of tumors has been shortened significantly, so too is it likely that the sixth edition of this text might be just over the horizon. But a lot has been learned since 2007, and detailed description and analysis of this new knowledge are finally available. One of the primary functions of a textbook is not just to convey what is new, but to analyze what has been published and then condense and summarize that information with an aim toward diagnostic and clinical relevancy. Professor Speight has done a masterful job of condensing our knowledge of these cysts into a readable and relevant format. This text is a must for anyone involved in the diagnosis and treatment of cysts of the head and neck. Improving our understanding of this group of lesions improves the quality of care we can provide our patients. And ultimately, that is what it's all about.

John M. Wright, DDS, MSRegents Professor Diagnostic Sciences Texas A&M University College of Dentistry Dallas, Texas USA

This edition is dedicated to the memory of Mervyn Shear, who must first be acknowledged for his research and scholarship over many years that laid the foundations for all the editions of this book. For this edition I specifically acknowledge Mervyn's support and permission to restructure the book and to undertake a complete rewrite of the text, with an increased emphasis on some basic principles and on histopathology and differential diagnosis that may broaden the scope of the book, making it more accessible to a wider range of students and clinicians.

As in previous editions, we have relied heavily on the support and assistance of colleagues and on the research and scholarship of our predecessors. In particular, I would like to draw attention to a number of outstanding giants of the subject on whose shoulders we stand, and who are heavily cited in the text or with whom, over many years, we have shared and discussed cases: Mario Altini, Jerry Bouquot, Roger Browne, Roman Carlos, Geoff Craig, Ricardo Gomez, Robert Gorlin, Malcolm Harris, Jos Hille, Fumio Ide, Ivor Kramer, TieJun Li, Hans Philipsen, Jens Pindborg, Finn Prætorius, Peter Reichart, Paul Stoelinga, Takashi Takata, Paul Toller, Willie van Heerden, Pablo Vargas, and John Wright. Some of these are no longer with us, some I have never met, but most have become good friends and colleagues.

For the preparation of this fifth edition I would like to thank my colleagues, past and present, in the Unit of Oral and Maxillofacial Pathology, University of Sheffield, for their patience, for many discussions and critical comments on the text, and for their assistance in retrieving and photographing cases. Daniel Brierley, Geoff Craig, Lisette Collins, Paula Farthing, Keith Hunter, and Ali Khurram have commented freely on my thoughts and ideas about cysts and have also provided assistance in finding appropriate cases for the illustrations. Chris Franklin and Adam Jones have allowed me access to their data on the incidence of cysts and oral biopsies.

Many colleagues have selflessly provided clinical pictures, radiographs, and photomicrographs, and a number of publishers have allowed us to reproduce figures that have been previously published. For this we are very grateful, and each has been acknowledged in the relevant figure legends.

A major aim of this new edition was to broaden the readership and make the text more accessible to students, trainees, and non‐specialist pathologists and clinicians. A number of colleagues have been kind enough to read early drafts of chapters and freely provided very helpful and constructive comments that have facilitated this aim: Daniel Brierley, Lisette Collins, Paula Farthing, Ali Khurram, Liam Robinson, Willie van Heerden, and John Wright.

I am also especially grateful to my colleague and friend Professor John Wright, who very kindly agreed to write the forward to this edition.

Classifications

Cysts of the JawsOdontogenic Cysts Odontogenic Cysts of Inflammatory Origin Odontogenic Cysts of Developmental Origin Non‐odontogenic Cysts and Pseudocysts Non‐odontogenic Cysts of the Jaws Pseudocysts of the Jaws

Cysts of the Salivary and Minor Mucous Glands Cysts of the Major and Minor Salivary Glands Cysts of the Maxillary Sinus

Developmental Cysts of the Head and Neck

Frequency of Cysts of the Oral and Maxillofacial Regions

There is no single satisfactory classification of cysts of the head and neck region. In part this is because terminology varies across the world, but also because classification systems may be developed to serve different purposes. Some authors have tried to subdivide lesions into multiple variants based on histological or clinical features, but this has little clinical utility in terms of planning management. Detailed classifications that include variants are nevertheless useful for research, and occasionally a reported variant may eventually emerge as a new entity. A well‐known example of this is the reporting of an orthokeratinised variant of the odontogenic keratocyst (Wright 1981 ), which over time was shown to have distinctive clinicopathological features and is now recognised as an entity – the orthokeratinised odontogenic cyst. Other variants, however, such as the bay or pocket variant of the radicular cyst, have little bearing on clinical management and are of academic interest only. There is a tendency for classifications to be overcomplicated by pathologists, who often describe subtle histological variations as new ‘entities’. The most useful classifications should be simple, should use globally recognised terminology, and should be easy to use and relevant for clinicians who treat the lesions. A straightforward uniform nomenclature facilitates communication between clinical specialties and enables precise reporting of lesions for statistical and research purposes.

International standards for classifications were first developed by the World Health Organization (WHO), which set up a global project for the histological classification of tumours in 1952 (reviewed by Sobin 1971 ). The project involved collecting samples of lesions that were reviewed by groups of international experts, who agreed a uniform nomenclature and established practical and clinically relevant diagnostic criteria. The first classification of cysts of the jaws was published in 1971 in Histological Typing of Odontogenic Tumours, Jaw Cysts and Allied Lesion s (Pindborg and Kramer 1971 ). This first edition was deliberately inclusive and provided a comprehensive classification of jaw lesions so that all neoplasms and cysts of the odontogenic tissues could be considered in context, allowing pathologists and clinicians to make an informed diagnosis. The second edition, published in 1992, also included cysts of the jaws (Kramer et al. 1992 ), but the third edition (Barnes et al. 2005 ) omitted cysts and restricted the classification to tumours and a range of ‘tumour‐like’ lesions. Subsequently, the fourth (El‐Naggar et al. 2017 ) and fifth editions (WHO 2022a , b) have included the odontogenic cysts and have restored the status of the book as a complete classification of lesions of the odontogenic tissues.

It is important to note that the WHO classifications still maintain the original principles of simplicity, relevance, and a uniform and well‐recognised terminology. Thus the WHO books should be regarded as a guide to terminology, definitions, and diagnostic criteria. They are not comprehensive and do not include detailed considerations of variants, unusual features, or differential diagnosis. In this book we have adopted a simple working classification of the odontogenic cysts using the WHO terminology. We do not include detailed subdivisions or variants in the classifications, but in each chapter we discuss terminology and classification, and include details of variants of each lesion where this might have a bearing on diagnosis or management.