George P. Wysocki

Relative incidence of odontogenic tumors and oral and jaw cysts in a Canadian population

The diagnoses of 40,000 consecutively accessioned oral biopsies from the Oral Pathology Diagnostic Service, University of Western Ontario, London, Canada, were reviewed. All odontogenic neoplasm, neoplasm-like lesions (tumors), and true cysts of the oral tissues and jaws were listed. Clinical data were reviewed, and microscopic diagnoses were confirmed for cases in which diagnoses were ambiguous. Records of all cases were examined to identify distant referrals that were not representative of the study population. Of a total of 445 (1.11%) odontogenic tumors, 392 (0.98%) were lesions from patients in the usual local drawing area of the biopsy service; 53 were referred from distant centers. From the local population, odontomas were by far the most common tumor (51.53%) followed by ameloblastomas (13.52%) and peripheral odontogenic fibromas (8.93%). Locally, radicular (periapical) cysts were the most common odontogenic cyst (65.15%) followed by the dentigerous cyst (24.08%) and the odontogenic keratocyst (4.88%). The most common nonodontogenic cyst was the nasopalatine duct cyst that accounted for 73.43% of this subset of cysts. Surprisingly few studies of this type are available, especially for odontogenic tumors. These data are important to assess geographic differences in the incidence of lesions and to allow clinicians to make realistic judgments in counseling patients before biopsy about the probability of diagnosis and risks associated with nonspecific clinical or radiographic lesions.

Fibrous hyperplasia of the gingiva: A side effect of cyclosporin A therapy

Abstract The clinical and histopathologic findings in six patients with gingival fibrous hyperplasia associated with cyclosporin A (CyA) therapy are described. The clinical and histopathologic findings are considered to be indistinguishable from the gingival hyperplasias induced by the anticonvulsant drug, phenytoin (diphenylhydantoin).

The small dentigerous cyst: A diagnostic dilemma

The dentigerous (follicular) cyst is recognized as one of the most common lesions of the jaws. Clinical, radiographic, histologic, and prognostic characteristics are well established for medium to large pericoronal cysts that are lined by nonkeratinized stratified squamous epithelium. However, it can be difficult, if not impossible, to distinguish between a small dentigerous cyst and a large dental follicle despite the availability of both radiographic and histologic information. Epidemiologic data derived from a comparative study of 1662 dentigerous cysts and 824 dental follicles showed considerable overlap in age distribution and site predilection and were therefore of minimal use in reaching a final diagnosis. At present, it appears that identifying a cystic cavity at the time of surgery may be the only reliable way to arrive at a definitive diagnosis when radiographic and histologic features are insufficient to distinguish between a small dentigerous cyst and a large dental follicle.

Peripheral odontogenic fibroma

The peripheral odontogenic fibroma is characterized by a fibrous or fibromyxomatous proliferation that contains varying amounts of odontogenic or presumed odontogenic epithelium. It has been considered a rare gingival neoplasm that, because of a lack of follow-up information in most reported cases, has had an unknown biologic behavior. Clinical data from this study indicate that the lesion is more common than previously reported and that it has a significant recurrence rate. Light and electron microscopic data reveal a relatively broad spectrum of epithelial and mesenchymal components, including a rare granular cell type. Because the presence of both epithelial and mesenchymal elements are required for its diagnosis, the lesion is logically classified as a mixed epithelial/mesenchymal odontogenic tumor, rather than a purely mesenchymal tumor.

Epithelial-myoepithelial carcinoma of salivary glands

Four cases of epithelial-myoepithelial carcinoma of salivary gland origin are presented and discussed. The mean age of these four patients was 68 years, with an age range of 51 to 78 years. Three of the patients were women, and one was a man. This article emphasizes the light microscopic, histochemical, and ultrastructural features of the neoplasm. Electron microscopic examination of glutaraldehyde-fixed fresh tissue and previously formalin-fixed tissue reveals that the characteristic clear cytoplasm of abluminal cells is caused, in part, by glycogen storage granules and the paucity of organelles but largely by an artifact of fixation.

Benign migratory glossitis in patients with juvenile diabetes

The prevalence of tissue type HLA-B15 has been shown to be higher in atopic patients with benign migratory glossitis and in patients with insulin-dependent diabetes mellitus than it is in the general population. Despite this apparent link, the possible relationship between benign migratory glossitis and insulin-dependent diabetes mellitus does not appear to have been investigated previously. This study of 87 diabetic patients and 105 age- and sex-matched nondiabetic control subjects revealed a fourfold increase in the prevalence of benign migratory glossitis in the diabetic group. These results suggest that benign migratory glossitis may be linked to diabetes mellitus and that further investigation of this association is warranted.

Acinic cell tumors of minor salivary glands

The occurrence of acinic cell tumors in the minor salivary glands of the oral cavity has, until recently, been considered exceptional. However, three recent papers have documented the details of fifty-two such cases. The purpose of the present article is to record the clinical information and histologic findings in six additional, previously unreported, examples of this tumor in the minor salivary glands.

The differential diagnosis of globulomaxillary radiolucencies.

The differential diagnosis of radiolucencies which occur in the globulomaxillary region includes a variety of odontogenic cysts and tumors, inflammatory lesions, and a number of nonodontogenic conditions. The accumulating embryologic and histopathologic evidence suggests that the development of fissural cysts in this region of the maxilla is highly unlikely. If they occur at all, such cysts must be extremely rare indeed and therefore do not belong on any clinicians list of differential diagnoses.

Metallothionein in human gingival amalgam tattoos

Amalgam tattoos occur when small particles of dental amalgam, composed largely of silver (Ag) and mercury (Hg), are inadvertently implanted into oral soft tissues during dental procedures. Metallothioneins (MTs) are ubiquitous, low molecular weight, cysteine-rich, metal-binding proteins that are inducible by many agents including metals and may be involved in the detoxification of toxic metals such as Hg. In this study, the correlation between MT expression and amalgam tattoos in human gingiva was investigated using energy-dispersive X-ray microanalysis (EDX) and immunohistochemical techniques. Light microscopically, amalgam tattoos presented as either fine granular particles or larger discrete opaque globular particles in connective tissues. EDX revealed the smaller particles to be silver sulphide (Ag(2)S), while the larger particles exhibited a shell of Ag(2)S that contained irregularly distributed masses of Ag and Hg. Particles of tin (Sn) were also found. No MT staining was observed in collagen, fibroblasts or blood vessels in areas exhibiting abundant amounts of embedded fine granular Ag(2)S particles. Blood vessels exhibiting relatively few amalgam particles stained positively for MT. Cells with the morphological features of histiocytes located directly adjacent to larger pieces of amalgam showed intense MT staining. These results indicate that amalgam tattoos contain no Hg or free Ag except in large globular pieces of amalgam, which still contain Hg and which induce MT expression in adjacent histiocytes. This suggests that Hg leaching from impacted dental amalgam particles induces MT, while residual Ag(2)S and Sn particles do not. MT may therefore act to reduce Hg exposure in patients with amalgam tattoos.

Predentin changes in patients with chronic renal failure

Morphometric studies were carried out on teeth extracted from normal human patients and compared with those extracted from patients suffering from chronic renal failure and patients being treated by chronic hemodialysis. The findings revealed that the predentin layer in patients suffering from chronic renal failure and patients undergoing chronic hemodialysis was significantly thicker than normal. These findings suggest that predentin is the metabolic equivalent of osteoid in bone and that increases in the predentin thickness may therefore be a reliable indicator of osteomalacia. It is suggested that the term odontomalacia be used to describe the changes occurring in the dentin of these patients.