Erich J. Raubenheimer

Intraoral salivary gland neoplasms ; a retrospective study of seventy cases in an African population

Intraoral salivary gland neoplasms diagnosed in the Department of Oral Pathology, Medical University of Southern Africa, Medunsa, were reassessed and revised with regard to histologic diagnosis. New entities and subclassifications that have been described in recent years were taken into account. Seventy cases were diagnosed during an 8-year period, and the sample consisted of black patients only. Benign mixed tumor was the most common entity and accounted for 48% of all tumors. Polymorphous low-grade adenocarcinoma comprised 15.7% of the sample and was the most frequent malignant tumor. The mean age of patients with benign and malignant tumors were 36.5 and 49.8 years, respectively (p less than 0.05), and the palate was the most common site involved. Geographic differences do exist in the pattern and pathology of intraoral salivary gland neoplasms when compared with findings in other studies.

The nature of fibrous dysplasia

Fibrous dysplasia has been regarded as a developmental skeletal disorder characterized by replacement of normal bone with benign cellular fibrous connective tissue. It has now become evident that fibrous dysplasia is a genetic disease caused by somatic activating mutation of the Gsα subunit of G protein-coupled receptor resulting in upregulation of cAMP. This leads to defects in differentiation of osteoblasts with subsequent production of abnormal bone in an abundant fibrous stroma. In addition there is an increased production of IL-6 by mutated stromal fibrous dysplastic cells that induce osteoclastic bone resorption.

Maxillofacial hydatid cysts

We report 2 cases of hydatid cysts occurring in the submandibular gland and buccal submucosa, respectively. Our first case occurred in the submandibular salivary gland of a 20-year-old woman and the second involved the buccal submucosa of a 6-year-old boy. Both diagnoses were made after the excision of the lesions. Both patients were evaluated after surgery, and both were followed up, but no other organs were involved.

LOW-GRADE INTRAOSSEOUS OSTEOSARCOMA OF THE JAWS

Two cases of low-grade intraosseous osteosarcomas are reported, bringing the total number of such osteosarcomas in the jawbones documented in recent literature to six. Our first case involved the maxilla of a 69-year-old man and the second involved the mandible of an 18-year-old girl. In clinical and microscopic appearance, these neoplasms resemble benign proliferations in many respects. Subtle differences include cortical bone destruction, soft tissue infiltration, irregular bone production with foci of abundant osteoid, and mild cellular atypia. Complete removal at the first attempt is of paramount importance, inasmuch as a significant percentage of these neoplasms recur as high-grade osteosarcomas if they are inadequately treated.

Histogenesis of the chequered pattern of ivory of the African elephant (Loxodonta Africana)

This study aimed to propose a hypothesis on the events which lead to the development of the characteristic chequered pattern of elephant ivory. Twenty fragments of ivory and six elephant tusks were obtained through the National Parks Board of South Africa. Polished surfaces were prepared in sagittal and longitudinal planes and the characteristics of the distinctive chequered pattern described. Light- and electron-microscopical techniques and image analyses were employed to determine the morphological basis of the pattern and to describe the spatial distribution, density and morphology of the dentinal tubules. These investigations showed that the distinctive pattern was the result of the sinusoidal, centripetal course followed by dentinal tubules. The apical, slanted part of the sinusoidal curve is the result of the centripetally moving odontoblast, which, during formation of ivory, progresses towards the centre of the tusk on a decreasing circumference. It is suggested that this leads to cell crowding, increased pressure between odontoblasts and subsequent apical movement of their cell bodies, cell degeneration and fusion. Odontoblastic degeneration and fusion probably relieve the pressure between the crowded odontoblasts by reducing their numbers and the remaining odontoblasts now orientate their centripetal course towards the tip of the tusk, thereby forming the anterior-directed part of the sinusoidal path of the tubule. As odontoblasts progress centripetally the diameter of the pulpal cavity decreases further and the processes of apical movement, fusion and degeneration of odontoblasts are repeated. This occurs until the pulpal cavity is obliterated.

The myoepithelial cell: embryology, function, and proliferative aspects

Myoepithelial cells form an integral part of the secretory and ductular portion of most glands. They share a common origin with lumenal epithelial cells and influence proliferation and differentiation of developing terminal glandular buds by producing a scaffold of basement membrane proteins. Their contractile capacity, controlled by hormonal and neural mechanisms, plays an important role in propulsion of secretions. Furthermore, myoepithelial cells maintain glandular structural integrity and transport metabolites to secretory cells. The advent of modern immunochemistry made identification of specific myoepithelial cell markers possible which facilitated studies on their presence and behavior in disease processes. Although the significance of many myoepithelial alterations is speculative, some have proved valuable in determining the histogenesis of glandular lesions.

Geographic variations in the composition of ivory of: the African elephant (Loxodonta africana)

Tracing the source of origin of illegal ivory will contribute to the identification of poorly managed game parks and facilitate steps taken to prevent the African elephant from becoming extinct. This study was aimed at establishing a database on the composition of ivory obtained from elephant sanctuary areas in Southern Africa. Fragments of elephant ivory from seven geographically distinct areas in South Africa, Namibia and Botswana were analysed for inorganic and organic content. A total of 20 elements was detected in the inorganic fraction of ivory, some in concentrations as low as 0.25 microg/g. The concentrations of calcium, phosphate, magnesium, fluoride, cobalt and zinc showed statistically significant differences (p < 0.007) between ivory obtained from different regions. Analyses of the organic fraction identified 17 amino acids. Ivory from arid regions showed significantly lower proline plus hydroxyproline content and under-hydroxylation of lysine residues. This study indicates that chemical analyses of ivory could be beneficial in tracing the source of illegal ivory.

Multiple myeloma presenting with extensive oral and perioral amyloidosis

The case of a young adult patient, with a kappa-light-chain-secreting multiple myeloma and extensive oral and salivary gland amyloid deposits, is presented. This case illustrates the necessity of a multidisciplinary approach using biochemical, radiographic, and relevant histologic investigations in the diagnosis of multiple myeloma. Factors influencing the prognosis of this neoplastic condition are discussed. Microscopic examination of the oral amyloid deposits supports the suggested central role played by the macrophage in amyloidogenesis.

The prognostic significance of facial lymphoedema in HIV-seropositive subjects with Kaposi sarcoma

BackgroundKaposi Sarcoma (KS) is a multifocal angioproliferative neoplasm characterized by inflammation, oedema, neoangiogenesis and spindle cell proliferation. The pathogenesis of human immunodeficiency virus (HIV)-associated KS (HIV-KS) is multifactorial. HHV-8 is an essential factor but not in itself sufficient to cause HIV-KS, the development of which is influenced by HIV, by increased production of cytokines and by growth factors. Whether HIV-KS is a true malignancy or a reactive hyperplastic inflammatory condition is debatable.Results and ConclusionOedema of the face, legs and hands is a prominent feature of HIV-KS and is probably caused by lymphoedema related to the HIV-KS lesions. The cases of two HIV-seropositive subjects with KS-associated facial lymphoedema are reported. Extensive oral HIV-KS in association with facial oedema in the absence of anti-retroviral treatment appears to be an indication of a poor prognosis.

Gigantiform melanotic neuroectodermal tumor of infancy

Melanotic neuroectodermal tumor of infancy is a rare neoplasm of possibly neural crest origin, and it predominantly occurs in the premaxillas of infants less than 12 months old. Generally, the treatment of this benign pigmented lesion is conservative surgical excision. Long-term follow-up is imperative inasmuch as local recurrence and malignant transformation have been reported. A case with exceptional clinical features involving a 7-month-old child is presented.