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Noma (canrum oris) is a mutilating necrotizing disease of uncertain etiology, but it is accepted that it is caused primarily by a polybacterial infection with secondary ischemia. The consequent necrotizing fasciitis, myonecrosis, and osteonecrosis results in destruction of facial structures with severe functional impairment and disfigurement. It most frequently affects children, particularly in sub-Saharan Africa, who are malnourished or debilitated by systemic conditions including but not limited to malaria, measles, and tuberculosis; and less frequently debilitated HIV-seropositive subjects. In the vast majority of cases, in susceptible subjects, noma is preceded by necrotizing stomatitis. However, it has been reported, albeit rarely, that noma can arise without any preceding oral lesions being observed. Noma is not recurrent and is not transmissible.

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Pemphigus vulgaris, mucosal pemphigoid (mucous membrane pemphigoid), lichen planus, discoid lupus erythematosus and erythema multiforme are a group of immune-mediated mucocutaneous disorders characterised clinically by the formation of blisters, erosions or ulcers. The oral mucosa is often affected, and sometimes the disease is limited to the mouth. The target antigens, autoreactive immune responses, microscopic features, treatment and prognosis vary from one disease to the other. Treatment aims to eliminate exogenous risk factors, suppress the pathogenic immuno-inflammatory reactions, promote healing and prevent infection. The aim of this article is to provide the general dental practitioner with a succinct overview of the diagnostic, clinical, aetiopathogenic features and characteristics of, as well as treatment guidelines for oral pemphigus vulgaris and oral mucosal pemphigoid. Early diagnosis and treatment could prevent severe consequences of the disease in their full-blown forms.

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BACKGROUND: Before the 1930s, squamous cell carcinoma (SCC) of the oesophagus was almost unknown among black South Africans. From the 1930s the annual frequency rose. A dietary cause was sought, the staple diet of black people having changed from sorghum to maize (corn), with traditional beer being brewed from maize. Carcinogenic N-nitrosamines in traditional beer were suggested as a cause of SCC of the oesophagus, with Fusarium moniliforme, a corn saprophyte, thought to play a role. OBJECTIVES: To confirm the presence of N-nitrosamines in traditional beer and demonstrate a mechanism for the oncogenesis of oesophageal carcinoma. METHODS: Analysis by high-performance liquid chromatography was conducted for the identification of nitrosamines in traditional beer samples, and molecular docking studies were employed to predict the affinity between N-nitrosamines and the S100A2 protein. RESULTS: Carcinogenic N-nitrosamines were identified in all six samples of traditional beer examined (N=18 analyses), and docking studies confirmed a high affinity of the nitrosamine N-nitrosopyrrolidone with the S100A2 protein. This may result in the altered expression of the S100A2 protein, leading to tumour progression and prognosis. CONCLUSION: It is suggested that carcinogenic N-nitrosamines in traditional beer are a major factor in the causation of SCC of the oesophagus in black South Africans. N-nitrosamines have been shown to produce cancer experimentally, but there has not been conclusive epidemiological evidence that N-nitrosamines are carcinogenic to humans. This study is the first to demonstrate the potential link between N-nitrosamines and a human tumour.

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The color of normal skin and of oral mucosa is not determined by the number of melanocytes in the epithelium but rather by their melanogenic activity. Pigmented biopolymers or melanins are synthesized in melanosomes. Tyrosinase is the critical enzyme in the biosynthesis of both brown/black eumelanin and yellow/red pheomelanin. The number of the melanosomes within the melanocytes, the type of melanin within the melanosomes, and the efficacy of the transfer of melanosomes from the melanocytes to the neighboring keratinocytes all play an important role in tissue pigmentation. Melanin production is regulated by locally produced factors including proopiomelanocortin and its derivative peptides, particularly alpha-melanocyte-stimulating hormone (α-MSH), melanocortin 1 receptor (MC1R), adrenergic and cholinergic agents, growth factors, cytokines, and nitric oxide. Both eumelanin and pheomelanin can be produced by the same melanocytes, and the proportion of the two melanin types is influenced by the degree of functional activity of the α-MSH/MC1R intracellular pathway. The cause of HIV oral melanosis is not fully understood but may be associated with HIV-induced cytokine dysregulation, with the medications commonly prescribed to HIV-seropositive persons, and with adrenocortical dysfunction, which is not uncommon in HIV-seropositive subjects with AIDS. The purpose of this article is to discuss some aspects of melanocyte biology and HIV-associated oral melanin hyperpigmentation.

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The presence of melanocytes in the oral epithelium is a well-established fact, but their physiological functions are not well defined. Melanin provides protection from environmental stressors such as ultraviolet radiation and reactive oxygen species; and melanocytes function as stress-sensors having the capacity both to react to and to produce a variety of microenvironmental cytokines and growth factors, modulating immune, inflammatory and antibacterial responses. Melanocytes also act as neuroendocrine cells producing local neurotransmitters including acetylcholine, catecholamines and opioids, and hormones of the melanocortin system such as proopiomelanocortin, adrenocorticotropic hormone and α-melanocyte stimulating hormone, that participate in intracellular and in intercellular signalling pathways, thus contributing to tissue homeostasis.There is a wide range of normal variation in melanin pigmentation of the oral mucosa. In general, darker skinned persons more frequently have oral melanin pigmentation than light-skinned persons. Variations in oral physiological pigmentation are genetically determined unless associated with some underlying disease.In this article, we discuss some aspects of the biophysiology of oral melanocytes, of the functions of melanin, and of physiological oral pigmentation.

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Noma predominantly affects malnourished young children. The pathogenesis of noma is complex and multifactorial, involving interaction between local polybacterial infection on the one hand, and malnutrition, immunosuppression, or systemic bacterial or viral infections on the other hand. Noma is considered to be an opportunistic disease, but the immediate cause is uncertain. Immunosuppression associated with a high HIV load may be an important risk factor in South Africa. Cervicofacial necrotizing fasciitis, on the other hand, occurs mainly in adults. It is frequently a consequence of an odontogenic infection and is characterized by an irregular pattern of rapidly spreading necrosis of fascia, muscle, and skin. We present an unusual case of noma in a 32-year-old malnourished HIV-seropositive female with AIDS in whom, within a period of 3 days, the initial intraoral necrotizing process spread rapidly and caused circular full thickness perforating destruction of the lower lip. Prompt diagnosis and treatment brought about control of the active disease and limited the extension of the established noma and of progression of the disease at other affected oral sites.

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The effect of HIV infection on the prevalence and the rate of progression of chronic periodontitis is not clear. The aim of this study was to compare parameters associated with the severity of chronic periodontitis in terms of periodontal probing depths, gingival recession, plaque indexes, and bleeding indexes of HIV-seropositive subjects and healthy age-matched control subjects, and of HIV-seropositive subjects on highly active antiretroviral therapy and those not receiving such treatment. Two cohorts of subjects with chronic periodontitis were recruited for this study over a period of six months. There were 30 HIV-seropositive subjects, and 30 control subjects. Periodontal probing depths, gingival marginal recession, plaque indexes, and bleeding indexes were compared by HIV serostatus, the use of highly active antiretroviral therapy, and CD4+ T-cell counts. All participants were black persons between the age of 18 and 45 and were of a similar socioeconomic status and age. The results of this study indicate that chronic periodontitis in HIV-seropositive subjects is similar in terms of mean periodontal probing depth, gingival marginal recession, plaque index, and bleeding index to that in healthy age-matched control subjects, and a low CD4+ T-cell count does not appear to be a risk factor for increased severity of chronic periodontitis.

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BACKGROUND: Primary intraosseous salivary-type adenocarcinomas are rare neoplasms of uncertain histogenesis. The prevailing theories suggest origin from heterotopic salivary glands, odontogenic rests, or cystic epithelium. METHODS: A case of central adenoid cystic carcinoma is reported in a 53-year-old woman who presented with a painless swelling in the anterior segment of her lower jaw. Radiographic examination confirmed the presence of an expansile, radiolucent lesion within the mandible with a multilocular appearance. On light microscopy analysis, areas showing cribriform and tubular growth patterns; admixed cysts, some of which were characterized by the presence of localized plaque-like thickenings of their epithelial linings; and the formation of aberrant dental hard tissue were observed. RESULTS: The radiographic and histomorphologic findings highlight the potential misdiagnosis of this rare tumor. The findings also draw attention to an embryologic histogenetic concept for some central salivary neoplasms. CONCLUSION: The divergent salivary and odontogenic differentiation evident in this tumor signifies the pluripotential nature of derivatives of oral ectoderm.

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BACKGROUND: Calcifying odontogenic cyst was described first by Gorlin et al. in 1962; since then several hundreds of cases had been reported. In 1981, Praetorius et al. proposed a widely used classification. Afterwards, several authors proposed different classifications and discussed its neoplastic potential. The 2005 WHO Classification of Odontogenic Tumours re-named this entity as calcifying cystic odontogenic tumour (CCOT) and defined the clinico-pathological features of the ghost cell odontogenic tumours, the CCOT, the dentinogenic ghost cell tumour (DGCT) and the ghost cell odontogenic carcinoma (GCOC). METHODS: The aim of this paper was to review the clinical-pathological features of 122 CCOT, DGCT and GCOC cases retrieved from the files of the oral pathology laboratories from 14 institutions in Mexico, South Africa, Denmark, the USA, Brazil, Guatemala and Peru. It attempts to clarify and to group the clinico-pathological features of the analysed cases and to propose an objective, comprehensive and useful classification under the 2005 WHO classification guidelines. RESULTS: CCOT cases were divided into four sub-types: (i) simple cystic; (ii) odontoma associated; (iii) ameloblastomatous proliferating; and (iv) CCOT associated with benign odontogenic tumours other than odontomas. DGCT was separated into a central aggressive DGCT and a peripheral non-aggressive counterpart. For GCOC, three variants were identified. The first reported cases of a recurrent peripheral CCOT and a multiple synchronous, CCOT are included. CONCLUSIONS: Our results suggest that ghost cell odontogenic tumours comprise a heterogeneous group of neoplasms which need further studies to define more precisely their biological behaviour.

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Sclerosing polycystic adenosis (SPA) is a rare lesion of salivary glands with a striking resemblance to fibrocystic disease of the breast. Most of the 47 reported cases have occurred within the parotid gland, with only a single case being described within the buccal mucosa. We report an additional case of SPA of the buccal mucosa. The exact nature of this entity is unknown, but has up until recently believed to be a pseudoneoplastic reactive and inflammatory sclerosing process. Even though SPA has satisfied the criteria for monoclonality, the debate as to whether SPA represents a true neoplasm or a pseudoneoplastic inflammatory sclerosing process, with low-grade neoplastic potential continues. Awareness of the occurrence of this lesion in both major and minor salivary glands is important to promote its differentiation from other more sinister salivary gland pathology. Cure is effected by localized surgical excision and all reported cases of SPA show an excellent prognosis with no true recurrence or metastasis.

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BACKGROUND: Adenomatoid odontogenic tumour (AOT) is a benign odontogenic jaw lesion. The aim of this study was to update the biological profile of AOT. MATERIAL AND METHODS: Cases published in the literature and cases in files of co-authors were included. RESULTS: 550 new cases were retrieved, and of a total of 1082 cases analysed, 87.2% were found in the second and third decades. The M:F ratio was 1:1.9. 70.8% were of the follicular variant (extrafollicular: 26.9%, peripheral: 2.3%). 64.3% occurred in the maxilla. 60% of follicular AOTs were associated with unerupted canines. Nineteen cases of AOT (2.8%, M:F ratio was 1:1.4) were associated with embedded third molars. Twenty-two peripheral AOTs (2.3%, M:F ratio was 1:5.3) were recorded. The relative frequency (RF) of AOT ranged between 0.6% and 38.5%, revealing a considerably wider AOT/RF range than hitherto reported (2.2-7.1%). CONCLUSIONS: This updated review based on the largest number of AOT cases ever presented, confirms the distinctive, although not pathognomonic clinicopathological profile of the AOT, its worldwide occurrence, and its consistently benign behaviour.

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The follicular variant of the adenomatoid odontogenic tumor (AOT) is thought to originate from the reduced enamel epithelium of the dental follicle. The origin of the extra-follicular variant however, remains less clear. This paper presents a case of an extra-follicular AOT, which we believe originated from the epithelial lining of a unicystic ameloblastoma, and reviews the literature. The available evidence seems to indicate that some extra-follicular AOTs might arise as secondary phenomena within pre-existing odontogenic cysts or cystic tumors.

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There is considerable confusion in the literature regarding the terminology and distribution of cysts and pseudocysts of the maxillary antrum, which are therefore often lumped together as dome-shaped shadows on the floor of the maxillary sinus. We report a case of a mucocoele of the maxillary antrum that occurred in a 25-year-old male and review the clinical, radiographic and histological features of cysts and pseudocysts of the maxillary sinus including antral mucocoeles, postoperative maxillary cysts, pseudocysts and retention cysts; and highlight some of the pertinent distinguishing features. Awareness of the appropriate nomenclature and correlation of clinical, radiographic and histological features will generally result in the correct diagnosis and proper treatment.

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Herpes zoster is a common viral infection, the oral soft tissue manifestations of which are widely known and recognized. Reports of spontaneous tooth exfoliation and jaw osteonecrosis following herpes zoster infection in the distribution of the trigeminal nerve are extremely infrequent and sporadic, with only 39 cases being reported in the literature. We report an additional case of mandibular osteomyelitis and spontaneous tooth exfoliation following herpes zoster infection, which occurred in the left mandible of a 70-year-old diabetic man; however, our case also showed CMV co-infection. The role of CMV in the pathogenesis of the osteonecrosis remains uncertain. Awareness of the possibility of CMV co-infection in various oral diseases including oral ulcers, Kaposi's sarcoma, and herpes zoster infections especially in immunocompromised patients is important, since spread of the CMV can easily occur to other sites with potentially fatal consequences. Early diagnosis can lead to effective treatment and prevention of complications.

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INTRODUCTION: Information on histopathological changes within sinus mucosa is lacking, both in the general population, and in subjects with specific facial morphology and chronic respiratory obstruction. AIMS AND OBJECTIVES: To provide baseline data of the frequency and nature of pathological changes in the maxillary sinus in a specified group of patients. METHODS: 119 patients undergoing elective maxillary osteotomies were selected. These included patients with (70) and without (49) vertical maxillary excess (VME), and mouth and nasal breathers. The frequency and nature of the histopathological changes within the maxillary antral lining were recorded. RESULTS: Patients ranged from 13 to 47 years, with a M:F ratio of 1:2.4. The findings included congestion (95%), submucosal oedema (90%), retention cysts (26%), true polyps (4.6%) and inflammation. There was eosinophilia (68%), basement membrane thickening (28%), goblet cell hyperplasia (95%) and dystrophic calcification (59%). CONCLUSIONS: A significant degree of sinus pathology was found in this specified group of patients. This was probably due to their living in a polluted urban environment. In the presence of such widespread pathological changes and the virtual impossibility of obtaining "normal" control tissue, investigators may find it impossible to correlate maxillary sinus pathology with either facial form or breathing pattern.

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Central granular cell odontogenic tumors are rare, with only 30 cases having been reported. The tumors usually occur in the mandibular molar area and are seen as localized painless swellings in patients older than 40 years. We report an additional case that occurred in the posterior mandible of an elderly black woman. All reported cases of this tumor are benign, and cure is effected by localized surgical excision. Ultrastructurally, the cells contain numerous lysosomes and phagocytic vacuoles. Immunohistochemically, the granular cells were positive for vimentin, CD68, muramidase, carcinogenic embryonic antigen, and bcl-2. These features support a mesenchymal origin with a possible histiocytic lineage for the granular cells. Awareness of the occurrence of this neoplasm is important to promote detection and differentiation from other intraoral granular cell lesions.

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OBJECTIVES: In this retrospective study, we defined the clinicopathologic characteristics of oral Kaposi's sarcoma (KS) and determined the presence of human herpesvirus 8 in the oral lesions in a group of South African patients. These results were compared with similar data from patients in developed countries. STUDY DESIGN: Eighty-one cases of oral KS were retrieved from the departmental archives. Fourteen patients with oral pyogenic granuloma served as control subjects. DNA was extracted by using a modified phenol chloroform extraction method and amplified by using polymerase chain reaction. If beta-globin DNA sequences could not be demonstrated, the patient was excluded from the study. RESULTS: Of the 81 patients included in the study, 68 (84%) had been diagnosed since 1997. Oral KS was often the first presenting sign of human immunodeficiency virus infection. Some of the lesions exceeded 4 cm in diameter. The most commonly affected site was the palate (37 patients), followed by the tongue and gingiva. Multiple oral sites were frequently involved. The mean age of the patients was 34.7 years (range, 2-58 years). The male-to-female ratio was 1.31 to 1. Most of the patients (94%) were black. Human herpesvirus 8 DNA sequences were detected in 44 of the 45 cases of oral KS in which the DNA was analyzed, and in 1 case of pyogenic granuloma. CONCLUSIONS: The only significant clinicopathologic differences in findings between our study and previous studies in developed countries were (1) the male-to-female ratio, (2) the preponderance of black patients, and (3) the more frequent involvement of the tongue. There are no studies reporting the clinicopathologic characteristics of oral KS in populations of developing countries.

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The head and neck region constitutes the second most common site of involvement for synovial sarcoma, accounting for up to 10% of all cases. Intraoral synovial sarcoma is rare; in fact, only 29 cases have been reported. We describe 2 additional cases occurring in the floor of the mouth and the retromolar area. In addition, we have reviewed the clinicopathologic features of the previously reported cases. Our findings indicate that intraoral lesions differ from lesions occurring in other sites only in that intraoral cases show a greater male predilection and a generally painless initial presentation. In the oral cavity, the possible earlier detection, easy accessibility, and small size render these tumors more likely to be amenable to surgical excision, but their biologic behavior remains aggressive, with a poor long-term prognosis. Awareness of the potential for the occurrence of this neoplasm in the oral cavity is important for effective histopathologic diagnosis of intraoral spindle cell malignancies.

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