Salivary gland tumours. A review of 2410 cases with particular reference to histological types, site, age and sex distribution

To date the British Salivary Gland Tumour Panel has accumulated 2569 salivary gland tumours. Of these, 2410 were primary epithelial salivary gland tumours and these formed the basis of the present study. The diagnosis of individual tumours was based on the World Health Organisation classification. Tumours were analysed according to histological type, site, age and sex. The principal site was the parotid and the combined minor (oropharyngeal) glands formed the second largest group. Pleomorphic adenomas formed the largest group of tumours in most sites, but were particularly common in the parotid. The frequency of malignant tumours increased with age after the third decade and was maximal in the eighth decade. Malignant tumours were more common in the submandibular and the minor glands than in the parotid. In the sublingual gland six out of seven tumours were malignant.

WHO International Histological Classification of Tumours. Tentative Histological Classification of Salivary Gland Tumours

The principles of the proposed modified WHO Histological Typing of Salivary Gland Tumours are based on the following: 1) The classification of tumours is oriented to the routine work of the practicing surgical pathologists, those who do not see tumours of the salivary glands very often. The inclusion of rare, but clearly defined tumour entities should be helpful to surgical pathologists consulting with clinical specialists. 2) The different types of carcinomas must be distinguished not only by precise histopathological definitions, but also considering differences in prognosis and treatment. For example, the polymorphous low-grade adenocarcinoma and the epithelial-myoepithelial carcinoma are characterized by a relatively good prognosis in contrast to the salivary duct carcinoma. 3) Special points of discussion are: subclassification and grading of carcinomas (e.g. acinic cell carcinoma, mucoepidermoid carcinoma and adenoid cystic carcinoma), the classification of basal cell tumours (basal cell adenoma, basal cell carcinoma, solid type of adenoid cystic carcinoma), malignant tumours in pleomorphic adenomas and the differential diagnosis between primary tumours and metastases.

Tumours of the minor (oropharyngeal) salivary glands: a demographic study of 336 cases

There are 2410 primary epithelial salivary gland tumours in the files of the British Salivary Gland Tumour Panel. Of these tumours, 336 (14%) involved the minor (oropharyngeal) salivary glands, and these were studied in the present investigation. Individual tumours were diagnosed according to the WHO Classification. The percentage of malignant or potentially malignant tumours (46%) was much higher than in major glands (18%), and in some of the less common intraoral sites all the tumours were malignant. The principal sites were the palate (54%), lips (21%) and buccal mucosa (11%), and, in these sites, pleomorphic adenoma was the most common tumour. Monomorphic adenomas accounted for 6% of palatal tumours, but 30% of lip salivary gland tumours. The most common malignant tumour was the adenoid cystic carcinoma. The results are compared with several other large surveys and with tumours of major salivary glands.

Oral cancer development in patients with oral lichen planus

There has been considerable controversy as to whether oral lichen planus (LP) has a premalignant potential. This study retrospectively examined the records of 241 British patients with histologically confirmed LP seen during the 10-year period 1982-92. Nine patients (3.7%) were known to have developed well-differentiated invasive carcinoma or carcinoma in situ in an area of LP. Most carcinomas at presentation were in areas of atrophic and/or erosive LP, 6 were in patients older than 65 years, and 6 were on the tongue. The results support a small but clinically important premalignant potential for LP.

Warthin's tumor (cystadenolymphoma) of salivary glands. A clinicopathologic investigation of 278 cases

This article reviews the detailed clinical and pathologic features of 278 cases of Warthin's tumor (cystadenolymphoma) from the files of the British Salivary Gland Tumor Panel. The tumor was found exclusively in the parotid gland, where it accounted for 14% of the total primary epithelial parotid tumors. The male predominance (1.6:1) was lower than in many earlier reports, and this observation is discussed. Some histopathologic features of both epithelium and stroma were semiquantified, and the presence of ciliated epithelium in a few tumors was confirmed. The Warthin's tumors were subclassified according to the scheme proposed by Seifert and colleagues. No examples of metaplastic Warthin's tumor were seen, but a few tumors were extensively necrotic and probably infarcted. The age distribution of patients with stroma-poor Warthin's tumor supported the concept that this variant develops by progressive adenomatous growth of typical Warthin's tumor. The histogenesis of Warthin's tumor is discussed briefly.

Molecular changes in oral cancer may reflect aetiology and ethnic origin

Oral cancer, although uncommon in the Western world, accounts for up to 40% of all malignancies in parts of India and South East Asia. Recognised aetiological agents of oral cancer include tobacco and alcohol. This paper reviews the spectrum of molecular changes found in oral squamous cell carcinomas from Western (U.K., U.S.A., Australia) and Eastern (India, S.E. Asia) countries. p53 mutations are common in tumours from the West (47%) but are infrequent in the East (7%). Tumours from India and South East Asia are characterised by the involvement of ras oncogenes, including mutation, loss of heterozygosity (H-ras) and amplification (K- and N-ras), events which are uncommon in the West. The possibility that these genetic differences reflect aetiology and/or ethnic origin is discussed.

Oncocytic adenomas and oncocytic hyperplasia of salivary glands: a clinicopathological study of 26 cases

Twenty-six benign oncocytic lesions of the salivary glands, excluding Warthin's tumours, have been reviewed and criteria for their classification as oncocytoma, multifocal nodular oncocytic hyperplasia, diffuse oncocytosis, pleomorphic adenoma with oncocytic change or oncocytic monomorphic adenoma have been proposed. The histological and clinical features of this heterogeneous group of lesions are discussed. This analysis suggests that the majority of lesions initially categorized as oncocytomas were, in fact, either non-neoplastic or, alternatively, oncocytic change in other types of adenoma.

Animal models of intra-oral chemical carcinogenesis: a review

Early attempts to induce malignant oral tumours were largely unsuccessful, as the oral mucosa is considerably more resistant to the actions of chemical carcinogens than skin. The first consistent success came when strong carcinogens were applied to the hamster cheek pouch. This model remains the most popular for studies of intra-oral carcinogenesis and is discussed at length. The advantages and disadvantages are critically reviewed. The models of intra-oral carcinogenesis in extra-pouch sites in the hamster, mouse, rat and nonhuman primates are considered. The possible reasons for the relative resistance of oral mucosa to chemical carcinogens are discussed, particularly in relation to portals of entry and saliva. Finally, the relative merits of the more popular models of intra-oral carcinogenesis are briefly discussed.

Infarcted ('infected') adenolymphomas. A clinicopathological study of 20 cases

From a total of 323 adenolymphomas in the files of the British Salivary Gland Tumour Panel there were 20 cases (6.2%) which showed extensive necrosis, fibrosis and inflammation. The clinical and microscopical features of this distinctive subtype are described and it is suggested that infarction rather than infection is the more probable aetiological factor. In 40% of these infarcted adenolymphomas there was granuloma formation which mimicked tuberculosis or sarcoidosis and this possibility should be borne in mind when examining lesions in the parotid region.

Superficial mucoceles: pitfall in clinical and microscopic diagnosis

Extravasation mucoceles can be so superficial that they are seen as subepithelial blisters. These may rupture and cause superficial painful ulcers, which usually heal quickly. Occasionally such lesions may be seen in association with other mucosal disorders, particularly lichen planus, and a biopsy is undertaken to establish the diagnosis. In addition, the reporting pathologist may make an erroneous diagnosis of a subepithelial vesiculating disorder such as mucous membrane pemphigoid, especially when the clinical history is vague. Eight cases are described that illustrate some of the pitfalls in clinical and microscopical diagnosis of superficial mucoceles.

Pleomorphic adenomas of the major salivary glands: a study of the capsular form in relation to surgical management

This was a retrospective study of 126 primary pleomorphic adenomas to correlate capsular characteristics with tumour histopathology in relation to current surgical debate (parotidectomy versus local excision). Capsular thickness was measured by micrometry and tumours classified into subtypes (1-4). Evidence of fine needle aspiration damage (needle tracks, infarction) was sought. Minimal changes were seen in eight tumours. Tumour growth features (bosselations, enveloping) were present in 57% and 33%, respectively, also microinvasion (42%) and tumour 'buds' (12%). Parotid lesions possessed thicker capsules than submandibular tumours. There was little correlation between capsular thickness and cellular structure. The significant exception was large (> 25 mm) hypocellular parotid tumours which had thinner capsules and could be vulnerable to operative rupture. In 110 standard operations (parotidectomy, submandibular gland excision), capsular exposure was evident in 81%. Field irrigation is recommended to lessen the risk of tumour seeding. This study reaffirms many elements of capsular weakness and suggests that parotidectomy is the operation of choice.

Paget's disease of bone with particular reference to dentistry

Paget's disease of bone (osteitis deformans) is a relatively common disorder of uncertain aetiology. It is characterised by abnormal resorption and apposition of osseous tissue in one or more bones of the skeleton. This is a review of Paget's disease with particular reference to dentistry. The prevalence, aetiology, clinical features, radiography, histopathology, biochemistry, oral and dental manifestations, complications and treatment are discussed. One hundred and fifty-two reported cases of Paget's disease of the jaws have been analysed. The upper jaw was more frequently involved than the lower jaw in the ratio of more than 2:1. This survey shows a higher prevalence of Paget's disease in the mandible than previously recorded.

Epidermoid cyst of the buccal mucosa

An uncommon case of a large epidermoid cyst arising within the buccal mucosa is described.

Polymorphous low-grade adenocarcinoma of minor salivary glands--a report of three cases

Three cases of polymorphous low-grade adenocarcinoma of the minor salivary glands are described. Awareness of the pathological features and clinical behaviour of this recently described salivary gland malignancy allows for rational treatment planning and the prospect of an improved prognosis for the patient.

Oral epithelial dysplasia: clinical characteristics of western European residents

To detail the clinical presentation of oral epithelial dysplasia in a large cohort of residents in western Europe. Descriptive statistical analysis of the data were calculated using chi-square and Fisher's exact tests. Oral epithelial dysplasia manifested typically as a white or mixed red and white lesion on the tongue, buccal mucosa or floor of mouth. The peak age of presentation of oral epithelial dysplasia was the 6th decade. Most clinically detected lesions had only mild oral epithelial dysplasia. Although uncommon, lesions with severe dysplasia were most likely to arise on the floor of mouth or lateral border of tongue. Oral epithelial dysplasia is likely to manifest as a solitary white patch, but it is not possible to accurately predict the likely degree of dysplasia from the clinical features of such lesions.

Quantitative histological changes during early experimental carcinogenesis in the hamster cheek pouch

Sequential changes in the hamster cheek pouch epithelium following application of the carcinogen dimethyl benzanthracene have been assessed using stereological techniques. The most important progressive change found following cessation of carginogen painting appears to be an increase in the number and size of progenitor cells. Much of the marked increase in stratum corneum thickness seen in the early stages appeared to be related to a hyperplasiogenic rather than a neoplasiogenic action of the carcinogen.

Cheilitis glandularis: a case affecting the upper lip

Cheilitis glandularis is a rare disorder characterized by enlarged mucous glands, usually in the lower lip, and possibly predisposing to squamous cell carcinoma. A case affecting the upper lip is presented, which appears to be the first report of the disorder in that site.

Central odontogenic fibroma. A report of two controversial cases illustrating diagnostic dilemmas

Two unusual cases of central odontogenic fibroma are described and used to illustrate differential diagnostic problems in this controversial group of lesions. The first case had a cystic lesion noted on routine radiography in the left ramus of the mandible. This particular case was unusual histologically as it showed in addition to typical areas of odontogenic fibroma a small inflamed cyst lined by epithelium containing many hyaline bodies. The second case presented with anaesthesia of the right lower lip and an enlarged chin prominence. The lesion was diagnosed as an odontogenic fibroma but with a somewhat unusual histological appearance in that there were abundant areas of osseous metaplasia throughout the lesion.

Troublesome tumours 2: borderline tumours of salivary glands

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Giant cell lesions complicating fibro-osseous conditions of the jaws

Three patients who presented with giant cell lesions complicating ossifying fibroma, Paget's disease, and cherubism are reported. The giant cell lesions complicating ossifying fibroma and cherubism were diagnosed as giant cell granuloma (GCG), whereas the lesion complicating Paget's disease demonstrated more aggressive clinical and histologic features. The possible therapeutic and prognostic implications of these findings are discussed.

Plasma-cell gingivitis

Two cases of plasma-cell gingivitis identical to those previously reported as so-called "allergic gingivostomatitis" are presented. Glossitis and cheilitis were absent in the present cases, however. There was no evidence that the lesions were allergic in nature. The distinctive clinical and histologic features of the lesion are described.

Angiolymphoid hyperplasia with eosinophilia

Angiolymphoid hyperplasia with eosinophilia is a recently recognized lesion of skin consisting of atypical vascular paroliferation and variable inflammatory cell infiltration. A case is described here of a similar lesion presenting as an intraoral swelling. In addition to showing the histological features generally associated with angiolymphoid hyperplasia with eosinophilia, the present case exhibited striking smooth muscle proliferation.

Adult linear immunoglobulin A disease manifesting as desquamative gingivitis

Desquamative gingivitis is a manifestation of various dermatoses, particularly lichen planus and mucous membrane pemphigoid. A rare example of adult linear immunoglobulin A disease manifesting as desquamative gingivitis is presented. Although the initial clinical features were typical of desquamative gingivitis, the persistence of ulceration after dental extractions was unusual, and the management of the oral lesions proved difficult. The clinical, immunopathologic, and therapeutic aspects of linear immunoglobulin A dermatoses are reviewed.

Primary bone cyst of the mandibular condyle

Cysts of the mandibular condyle are rare and their diagnosis and treatment can be difficult. A case in a young girl is described where the histology was that of a solitary bone cyst but the presentation and behaviour more closely resembled an aneurysmal bone cyst.

Oral mucosal non-Hodgkin's lymphoma--a dangerous mimic

Reports of T-cell lymphomas in the oral cavity are rare. Most have presented as a persisting ulcerated swelling. This paper reports two men, one of whom presented with a short history of increasing facial swelling and pain apparently related to a lower premolar tooth, and the other who had recurrent oral ulceration in several sites over a period of years. These types of cases are likely to present initially to general dental practitioners.