颌骨牙源性钙化囊肿病变性质的探讨

目的：明确所谓牙源性钙化囊肿（calcifying odontogenic cyst,COC)各临床病理亚型的特点及其病变性能。方法：回顾分析21例被笼统诊断为COC病例资料,通过对临床、X线、病理、治疗及预后特点的综合分析,将本组病例分为囊肿、良性肿瘤和恶性肿瘤3类病损进行观察。结果：囊肿组16例（男性9例、女性7例）,10－19岁为高发年龄,前磨牙区好发,随访13例患者无复发。良性肿瘤组4例,临床病理表现各异,其中2例表现为所谓实性型COC,1例为COC伴发成釉细胞瘤,1例为COC伴发牙源性纤维黏液瘤;这组病例均发生于下颌,其中2例有多次复发史。恶性肿瘤组1例,肿瘤呈实性,除表现某些COC特点外,具有显著的组织学恶性特点。结论：以往被笼统归类为COC的病变可表现囊肿,良性肿瘤或恶性肿瘤等多种病理和行为特点,因此其命名和分类应作相应修改,临床治疗也应区别对待。     

Calcifying Odontogenic Cysts Associated with Odontomas: Confocal Laser Scanning Microscopy Analysis of 13 Cases

The so-called calcifying odontogenic cyst (COC) represents a heterogeneous group of lesions that exhibit a variety of clinico-pathologic features. It is an uncommon lesion and represents less than 2% of all odontogenic cysts and tumors. Recently, these lesions have been reclassified as calcifying cystic odontogenic tumors (CCOT), according to the new World Health Organization (WHO) classification. CCOT are frequently found in association with, or containing areas histologically identical to, various types of odontogenic tumors, such as complex/compound odontomas. This work analyzed clinical and histological data deriving from 13 patients affected by CCOT associated with odontomas. Moreover, a confocal laser scanning microscope (CLSM) analysis was undertaken to further a better understanding of the nature of this peculiar lesion.     

Calcifying odontogenic cysts associated with odontomas: confocal laser scanning microscopy analysis of 13 cases

The so-called calcifying odontogenic cyst (COC) represents a heterogeneous group of lesions that exhibit a variety of clinico-pathologic features. It is an uncommon lesion and represents less than 2% of all odontogenic cysts and tumors. Recently, these lesions have been reclassified as calcifying cystic odontogenic tumors (CCOT), according to the new World Health Organization (WHO) classification. CCOT are frequently found in association with, or containing areas histologically identical to, various types of odontogenic tumors, such as complex/compound odontomas. This work analyzed clinical and histological data deriving from 13 patients affected by CCOT associated with odontomas. Moreover, a confocal laser scanning microscope (CLSM) analysis was undertaken to further a better understanding of the nature of this peculiar lesion.     

Fibro-osseous lesions of the head and neck

This review aims to overview key histopathological features and provide diagnostic clues for a selection of the fibro-osseous lesions of the jaws and facial bones. These form a diverse group of conditions with differing aetiologies but similar histological appearances. Some may be part of more generalized systemic disease. It will become apparent that for this group of conditions, diagnosis cannot be made by examination of biopsy material by a pathologist in isolation, and both clinical and radiological correlation is needed. However, there are some subtle histopathological features that can allow one diagnosis to be favoured over all others, and these will be outlined. Identification of these features in material sent for histopathological analysis should assist the multidisciplinary team in making a definitive diagnosis.     

Use of calretinin in the differential diagnosis of unicystic ameloblastomas

AIMS: Calretinin, a 29-kDa calcium-binding protein is expressed widely in normal human tissues and tumours including both unicystic and solid and multicystic ameloblastomas. The histological distinction between unicystic ameloblastomas and certain non-neoplastic odontogenic cysts can be problematic. The objective of this study was to determine whether calretinin was expressed in the lining epithelium of odontogenic keratocysts, residual and dentigerous cysts and to determine whether this calcium-binding protein could be used to distinguish these cysts from the unicystic ameloblastoma. METHODS AND RESULTS: The lining epithelium in 22 cases of odontogenic keratocyst, 26 cases of residual cyst and 20 cases of dentigerous cyst were examined for the expression of calretinin. No positive epithelial staining was observed in any of these cystic lesions. In comparison, however, 81.5% of cases of unicystic ameloblastoma showed a coarse dark brown staining of the more superficial epithelial cell layers. Scattered positive stromal and epithelial cells were present; these were interpreted as mast cells. CONCLUSIONS: Calretinin appears to be a specific immunohistochemical marker for neoplastic ameloblastic epithelium and we suggest that it may be an important diagnostic aid in the differential diagnosis of cystic odontogenic lesions and ameloblastic tumours.     

Fibro-osseous lesions of the head and neck

This review aims to overview key histopathological features and provide diagnostic clues for a selection of the fibro-osseous lesions of the jaws and facial bones. These form a diverse group of conditions with differing aetiologies but similar histological appearances and some may be part of more generalized systemic disease. It will become apparent that for this group of conditions, diagnosis cannot be made by examination of biopsy material by a pathologist in isolation and both clinical and radiological correlation are needed. However, there are some subtle histopathological features that can allow one diagnosis to be favoured over all others which will be outlined here. Identification of these in material sent for histopathological analysis should assist the multidisciplinary team in making a definitive diagnosis.     

Odontogenic cysts: an update

The classification of odontogenic cysts has been widely debated and there has been much debate and controversy about the true nature of some of the lesions. Although cysts are common in the jaws, most are radicular cysts of inflammatory origin or simple dentigerous cysts. Others are less frequently encountered and may present diagnostic difficulties because of their varied features. The previous WHO classification, in 2005, redesignated a number of these lesions as true neoplasms, but this was controversial and was not based on sound evidence. For the latest WHO classification (2017), an international consensus group reappraised these lesions and agreed a terminology and new classification. This brief review presents this new classification, and explains the reasoning behind the agreed terminology.     

Odontogene Kieferzysten

Odontogenic cysts form a group of diseases whose origin is linked to the persistence of epithelium resulting from the complex embryonic development of the teeth and jaws within the connective tissue. Inflammatory reactions of the surrounding area of the persisting odontogenic epithelium accompany epithelium proliferation, which leads to the development of a gradually expanding cavity that supersedes the surrounding structure. The correlation between activity of the inflammatory reaction and the development of the epithelial proliferation results in a relatively broad variation of histological features of the cyst wall. Since classification of cyst forms depends on their topographical features, clinical information on the classification of variations is urgently needed. For the classification of their clinical course of development and, in particular, in order to differentiate them from cystic odontogenic tumors of the jaw region, a histological examination of cyst wall tissue is necessary, all the more so since the development of a carcinoma deriving from the odontogenic epithelium has only been described in very few cases.     

Pitfalls in odontogenic lesions and tumours: a practical guide

Lesions arising from odontogenic tissues of the jaws vary from very common to very rare. Some, such as radicular cysts, form a routine part of the diagnostic workload for histopathologists who report specimens from the head and neck, but many other lesions are rarely seen and can cause significant diagnostic difficulty for the non-specialist. These issues are compounded by the vagaries of dental disease (and terminology used by dentists and oral surgeons) and issues in the interpretation of radiographic images, which can be crucial to making a correct diagnosis. In this review article, we will discuss a number of areas of diagnostic difficulty, largely based on the authors experience in receiving tertiary referrals. This will focus on practical advice to help avoid the pitfalls in the diagnosis of odontogenic lesions.     

Odontoma-like tumours of squirrel elodont incisors--elodontomas

Since 2003, nine squirrels were presented at a South African veterinary dental practice with lesions in the maxilla consistent with the clinical, radiological and histological features of odontomas as described in prairie dogs, rats and mice. These odontoma-like masses have not previously been described in squirrels. This report describes the clinico-pathological features and possible pathogenesis of the lesions and proposes the term "elodontoma" for these hamartomatous odontogenic lesions in the jaws of animals with continuously erupting (elodont) teeth.     

Odontogenic classification of craniopharyngiomas: a clinicopathological study of 54 cases

Based on the striking histological similarity of craniopharyngiomas and some odontogenic tumours, we reclassified a series of 54 craniopharyngiomas (52 adamantinomatous and two papillary variants) according to the WHO classification of odontogenic tumours. Twenty-seven tumours (50%) corresponded histologically to calcifying odontogenic cyst, 13 tumours (24%) to ameloblastoma, and eight (15%) tumours showed features of both calcifying odontogenic cyst and ameloblastoma either within the same specimen or in specimens derived from different resections. Rare tumours included three cases resembling calcifying epithelial odontogenic tumour and one case resembling adenomatoid odontogenic tumour. No odontogenic counterpart could be established for papillary craniopharyngiomas. The two major subtypes, i.e. craniopharyngioma corresponding to calcifying odontogenic cyst and craniopharyngioma corresponding to ameloblastoma, did not differ in their basic clinical features. Our data confirm and extend the close histological resemblance between adamantinomatous craniopharyngioma and odontogenic tumours and cysts. Furthermore, although calcifying odontogenic cyst and ameloblastoma arising in the jaw differ in clinical presentation and outcome, our study did not reveal clinical differences for the corresponding subtypes of craniopharyngioma.     

A review of paediatric maxillofacial bone pathology

Maxillofacial bone pathology presents challenges related to its rarity and unique histomorphology, resulting from complex indigenous anatomical components, including odontogenic tissues, native bone and soft tissue. In the paediatric population, this is further compounded by the presence of developing tooth germs, with their unique histological features. Overlapping histological appearances of developing tooth germ components with odontogenic tumours, and between reactive processes and fibro-osseous/bone tumours are common challenges, necessitating knowledge of both the normal histology and the range of neoplastic, inflammatory and reactive processes occurring in this anatomical area. Erroneous diagnosis and limited clinicopathological correlation can result in inappropriate management, which may impact aesthetics, function and growth of developing maxillofacial bones. An overview of developmental, neoplastic, cystic and inflammatory lesions of paediatric maxillofacial bones is presented and diagnostic pitfalls discussed.     

Squamous cells in needle aspirates of subcutaneous lesions: a diagnostic problem

Analysis of 1,000 cases of fine-needle aspiration biopsies of subcutaneous lesions revealed 430 cases diagnosed as malignant. Squamous cell carcinoma represented 37% of the malignant neoplasms, and many of these cases were highly differentiated tumors. Although the presence of keratinized squamous cells in superficial aspirates is strongly suggestive of squamous cell carcinoma, other lesions may produce atypical squamous cells on aspiration biopsy and should be considered in the differential diagnosis. These include acanthotic ameloblastomas, metaplastic adenocarcinomas and Warthin's tumors, branchial cleft cysts, odontogenic keratocysts, and epidermal inclusion cysts. Two-needle aspirates from these cases were incorrectly interpreted as squamous cell carcinoma. The cytologic and some of the histologic characteristics of these lesions that may pose a diagnostic problem are presented. Careful evaluation of nuclear and cytoplasmic features, cellular background, clinical findings, and history is essential to avoid a false positive diagnosis of squamous cell carcinoma.     

Odontogenic cysts, odontogenic tumors, fibroosseous, and giant cell lesions of the jaws.

Odontogenic cysts that can be problematic because of recurrence and/or aggressive growth include odontogenic keratocyst (OKC), calcifying odontogenic cyst, and the recently described glandular odontogenic cyst. The OKC has significant growth capacity and recurrence potential and is occasionally indicative of the nevoid basal cell carcinoma syndrome. There is also an orthokeratinized variant, the orthokeratinized odontogenic cyst, which is less aggressive and is not syndrome associated. Ghost cell keratinization, which typifies the calcifying odontogenic cyst, can be seen in solid lesions that have now been designated odontogenic ghost cell tumor. The glandular odontogenic cyst contains mucous cells and ductlike structures that may mimic central mucoepidermoid carcinoma. Several odontogenic tumors may provide diagnostic challenges, particularly the cystic ameloblastoma. Identification of this frequently underdiagnosed cystic tumor often comes after one or more recurrences and a destructive course. Other difficult lesions include malignant ameloblastomas, calcifying epithelial odontogenic tumor, squamous odontogenic tumor, and clear-cell odontogenic tumor. Histologic identification of myxofibrous lesions of the jaws (odontogenic myxoma, odontogenic fibroma, desmoplastic fibroma) is necessary to avoid the diagnostic pitfall of overdiagnosis of similar-appearing follicular sacs and dental pulps. Fibroosseous lesions of the jaws show considerable microscopic overlap and include fibrous dysplasia, ossifying fibroma, periapical cementoosseous dysplasia, and low-grade chronic osteomyelitis. The term fibrous dysplasia is probably overused in general practice and should be reserved for the rare lesion that presents as a large, expansile, diffuse opacity of children and young adults. The need to use clinicopathologic correlation in assessing these lesions is of particular importance. Central giant cell granuloma is a relatively common jaw lesion of young adults that has an unpredictable behavior. Microscopic diagnosis is relatively straightforward; however, this lesion continues to be somewhat controversial because of its disputed classification (reactive versus neoplastic) and because of its management (surgical versus. medical). Its relationship to giant cell tumor of long bone remains undetermined.     

Cytological findings of odontogenic myxofibroma: A diagnostic dilemma

Odontogenic myxofibroma represents a rare slow‐growing benign neoplasm, which usually occurs in the second and third decades of life and rarely in children or adults over 50 years of age. Myxomas in general represent from 2.3% to 17.7% of all odontogenic tumors, and myxofibromas represent a small number of all myxomas. Limited evidence is present in literature regarding the cytological diagnosis of odontogenic myxoma/myxofibroma. We hereby report the cytomorphological features of a histologically confirmed case of odontogenic myxofibroma and the pitfalls of the cytological diagnosis. A painless jaw swelling in a young boy was aspirated. Scanty mucoid material was obtained. Cytology Smears were moderately cellular and showed a population comprising predominantly of singly scattered plump to fusiform cells with bipolar cytoplasmic processes showing mild to moderate atypia embedded within dense myxoid matrix and another population of cells arranged in clusters. Case was interpreted as low grade mesenchymal tumor. Subsequent biopsy confirmed it as odontogenic myxofibroma arising in a odontogenic keratocyst. Precise interpretation of intraosseous jaw lesions FNAC may not always be possible, but an attempt should be made to broadly classify the lesion as an inflammatory lesion, cystic lesion, giant cell lesion, fibro‐osseous lesion or as an odontogenic tumor. If dual population of odontogenic epithelium and mesenchymal cells embedded in myxoid matrix are identified in such aspirates, a possibility of myxoid odontogenic tumor may be suggested. Triple correlation of cytological, clinical and radiological findings can guide the surgeon for taking appropriate therapeutic decisions. Diagn. Cytopathol. 2016;44:329–333. © 2016 Wiley Periodicals, Inc.     

Current concepts of odontogenic tumours – an update

Odontogenic tumours can pose significant diagnostic challenges for the pathologist because of their relatively low incidence, somewhat overlapping histology and subtle differentiating features. Despite similar histology, the biological behaviour and appropriate therapy differ significantly between entities and accurate diagnosis is therefore essential. This article reviews the most common and important odontogenic tumours and highlights key features that will assist the pathologist to diagnose and appropriately classify these lesions. In addition, several new concepts of classification are discussed as reflected in the latest (2017) World Health Organization (WHO) classification of odontogenic tumours.¹ Important new developments in our understanding of the biology of these lesions are highlighted.     

Intraductal tubular neoplasms of the pancreas: an overview

Intraductal lesions of the pancreas are an uncommon but increasingly recognized group of entities mainly because of advances in imaging technology. In the past, precise categorization and understanding of true pancreatic intraduct neoplasms were hampered not only by their relative rarity but also because of the plethora of terminology and criteria used in nomenclature and diagnosis. Although significant progress has been made in the characterization of some of these lesions, as exemplified by intraductal papillary mucinous neoplasms, understanding of the rare intraductal tubular adenoma (ITA) and intraduct tubular carcinoma (ITC) continues to evolve. By definition, these are a group of intraductal, radiologically detectable neoplasms that can progress to or be associated with invasive adenocarcinoma and, as such, are precursor lesions to pancreatic ductal adenocarcinoma. Their often shared clinical and radiological features make precise histological diagnosis essential for appropriate management and optimal outcome. We provide an overview of these neoplasms and highlight recent developments in the understanding of ITA and ITC which have led to ITA being considered a variant of gastric-type intraductal papillary mucinous neoplasms and ITC being encompassed within the intraductal tubulopapillary neoplasm category. We also emphasize the distinguishing histological features to aid diagnosis of these rare lesions.     

Hybrid central giant cell granuloma and central odontogenic fibroma-like lesions of the jaws

Ten lesions from eight cases are presented of a rare intra-osseous jaw lesion with the combined histological features of giant cell granuloma and central odontogenic fibroma. Lesions arose over a wide age range and presented as monolocular or multilocular radiolucencies with cortical expansion and, in one case, perforation. Two lesions recurred after curettage, one being eradicated by a second curettage and one by conservative excision. Histologically, zones of typical giant cell granuloma lay in a fibrous stroma containing islands, strands and clusters of epithelial cells. Islands often contained duct-like spaces or hyaline basement membrane globules. Trabeculae of osteoid were present in five lesions. Recurrent lesions showed features identical to the initial lesion, including recurrence of the prominent epithelial component. These features cannot be conclusively ascribed to a variant of either giant cell granuloma, central odontogenic fibroma or aneurysmal bone cyst, but the clinical features are slightly more suggestive of giant cell granuloma. Attention is drawn to the characteristic and potentially confusing histological appearances. The presence of giant cell granuloma-like areas in central odontogenic fibroma-like lesions is associated with an increased risk of recurrence following curettage.     

Comprehensive keratin profiling reveals different histopathogenesis of keratocystic odontogenic tumor and orthokeratinized odontogenic cyst

Keratocystic odontogenic tumor is a cystic lesion that behaves more aggressively than other jaw cysts. One of its characteristic histologic features is a parakeratinized uniform layer of lining epithelium. A jaw cyst lined with orthokeratinized epithelium is called an orthokeratinized odontogenic cyst. These keratinized jaw cysts are thought to be separate entities, although their histopathogenesis has not been fully assessed. To better understand these lesions, we performed comprehensive immunohistochemical profiling of the keratin expression of each. Orthokeratinized odontogenic cysts expressed keratin 1, keratin 2, keratin 10, and loricrin, suggesting differentiation toward normal epidermis. Keratocystic odontogenic tumors expressed keratin 4, keratin 13, keratin 17, and keratin 19, which is a unique expression pattern reminiscent of a mucosal squamous epithelium and an epithelial appendage. In neonatal rat tooth germ, cells strongly positive for keratin 17 and keratin 19 were observed, specifically in the dental lamina, implying the origin of keratocystic odontogenic tumor. GLI2, a downstream effector of hedgehog signaling, was significantly expressed in keratocystic odontogenic tumor and basal cell carcinoma, accompanied with robust expression of keratin 17, mammalian target of rapamycin, and BCL2. The expression of these GLI2- or keratin 17-related factors was not significantly observed in orthokeratinized odontogenic cysts. These findings provide evidence to support the viewpoint that keratocystic odontogenic tumor and orthokeratinized odontogenic cyst are separate entities, and furthermore suggest their characteristic histology, pathogenesis, and biological behaviors.     

Current concepts of odontogenic tumours

Odontogenic tumours can pose significant diagnostic challenges for the pathologist because of their relatively low incidence, somewhat overlapping histology and subtle differentiating features. Despite similar histologies, the biological behaviour and appropriate therapy differ significantly between entities and accurate diagnosis is therefore essential. This article reviews the most common and important odontogenic tumours and highlights key features that will assist the pathologist to identify and appropriately classify these lesions. In addition, several new concepts of classification are discussed and important new developments in our understanding of the biology of these lesions are highlighted.