Molecular evidence supporting the neoplastic nature of odontogenic keratocyst: a laser capture microdissection study of 15 cases.

AIMS: The bland histology of odontogenic keratocyst (OKC) belies its capacity for aggressive behaviour. Genetic alterations of OKC have not been well studied. We examined the frequency and pattern of allelic imbalance on five different chromosome regions from 15 patients with OKC. METHODS AND RESULTS: Laser-assisted microdissection was performed on formalin-fixed paraffin-embedded tissue. Polymerase chain reaction analysis of extracted DNA targeted five polymorphic DNA markers (D3S1285, D9S161, D11S1316, D13S290, and TP53) representing chromosome regions 3p14, 9p21, 11q23, 13q12.1 and 17p13, respectively. All 15 cases of OKC were informative at a minimum of three of five loci, with 11 informative on all five loci. Twelve of 15 cases (80%) demonstrated loss of heterozygosity (LOH). Seven cases (47%) showed LOH at more than two DNA loci. The frequency of LOH was 5/11 (45%) at D3S1285, 3/15 (20%) at D9S161, 4/14 (29%) at D11S1316, 8/14 (57%) at D13S290 and 3/15 (20%) at TP53. CONCLUSIONS: The majority of OKCs harbour chromosomal abnormalities. This finding supports the supposition that OKCs are neoplastic. Furthermore, OKCs harbour allelic loss at some of the same loci identified in squamous cell carcinoma. This may aid in explaining the rare occurrence of squamous cell carcinoma arising in OKC.

Condyloma acuminatum and condyloma-like lesions of the oral cavity: a study of 11 cases with an intraductal component.

AIMS: We studied the clinicopathological features of 11 condyloma and condyloma-like lesions of the oral cavity with an unusual mixed pattern of exophytic and intraductal growth. The latter manifest as involvement of minor salivary gland ducts by the proliferative squamous lesions. This pattern of ductal involvement has not been previously described in oral condyloma. METHODS AND RESULTS: The clinical history was available for nine patients ranging in age from 17 to 73 years. Two were female and seven male. The buccal mucosa (five cases) was the most common site of occurrence, followed by the floor of mouth (two cases), lingual frenum (two cases), and hard palate (one case). All lesions exhibited exophytic and intraductal growth. The latter manifested itself as extension of the lesions into the excretory ducts of minor salivary glands. Underlying minor salivary glands, present in many of the excisional biopsy specimens, typically showed changes of obstructive atrophy. The exophytic components of all cases exhibited some degree of parakeratosis, and cryptic invaginations of parakeratin were typically present. Koilocytes were present in seven lesions and were equivocal in four. Mucous cells were present in the intraductal component of all cases and the intraductal component was never keratinized, but often papillary. A mild stromal-based, lymphocytic host response was present in three. A variably prominent neutrophilic infiltrate was present in the exophytic component of eight. Dysplasia was not present in any case. Five of 11 cases were positive with anti-human papillomavirus (HPV) and two of 11 cases were positive for in-situ hybridization probes directed against HPV 6/11. All cases were negative for HPV 16/18 and 13/33/35. CONCLUSIONS: Oral condyloma acuminatum may involve the excretory ducts of minor salivary glands. The diagnosis of oral condyloma acuminatum is difficult, as these lesions share considerable histological overlap with squamous papilloma. Finally, the relationship between these two lesions is incompletely understood.

Early soft tissue pathosis associated with impacted third molars without pericoronal radiolucency.

OBJECTIVES: This study was performed to histologically evaluate soft tissue pathosis in pericoronal tissues of impacted third molars that did not exhibit pathologic pericoronal radiolucency. STUDY DESIGN: One hundred impacted third molars without evidence of abnormal pericoronal radiolucency (follicular space <2.0 mm) were removed for reasons other than participation in this study, and the pericoronal tissues were submitted for histopathologic examination. Specimens were fixed and processed routinely and were stained with hematoxylin and eosin before independent evaluation by each of 2 oral pathologists. A subset of both diseased and healthy tissues underwent additional evaluation for the presence of proliferating cell nuclear antigen (PCNA) for assessment of cellular activity. RESULTS: Of the specimens submitted, 34% showed squamous metaplasia suggestive of cystic change equivalent to that found in dentigerous cysts. Soft tissue pathosis was significantly higher in patients over 21 years of age (P =.001). Five of 8 diseased specimens demonstrated PCNA uptake, whereas none of 10 healthy specimens were PCNA positive. CONCLUSIONS: These findings suggest that radiographic appearance may not be a reliable indicator of the absence of disease within a dental follicle. We conclude that the incidence of soft tissue pathologic conditions is higher than generally assumed from radiographic examination alone.

Precancerous and cancerous lesions of the oral cavity.

The purpose of this article is to provide the clinician with the clinicopathologic characteristics of oral cancer and its precursors. As can be seen by the previous discussion, numerous variables influence the formation of these lesions, and as yet we are unable to predict the progression of any single, premalignant lesion with certainty. Because of this, only astute clinicians, armed with a healthy level of suspicion, will be able to affect the prognosis of oral malignancies by recognizing these conditions at the earliest possible stage.

Small intestinal submucosa: utilization for repair of rodent abdominal wall defects.

Prosthetic graft material is often used for the repair of abdominal wall defects that result from trauma, infection, neoplastic, or congenital deformities. A new material, porcine small intestinal submucosa, has been successfully used as an arterial and venous graft material in both canine and primate animal models with graft patency and infection rates equal to autologous vein. On the basis of these studies, small intestinal submucosa was used as a graft material for the repair of a 2 x 2-cm full-thickness defect of the muscle and fascia in the rodent abdominal wall (N = 11). Two animals were euthanized at 1 week, 2 weeks, 4 weeks, 2 months, and 3 months. At the time of euthanization, no abdominal hernias were noted and only minimal intra-abdominal adhesions were observed. One animal died on postoperative day 5 as a result of a wound dehiscence. Histological analysis of the excised abdominal wall hernia repairs revealed moderate initial inflammation but with incorporation of small intestinal submucosa with minimal inflammation at 2 months. No evidence of graft-versus-host rejection was noted with hematoxylin and eosin stains and light microscopy. Porcine small intestinal submucosa merits further study as a graft material for abdominal wall replacement.

Small intestinal submucosa: utilization as a wound dressing in full-thickness rodent wounds.

Wound dressings are used as a temporary wound covering to promote wound healing, control wound exudate, and decrease wound contamination as well as evaporative water loss. A new material, porcine small intestinal submucosa, has been used successfully as an arterial and venous graft in both canine and primate animal models with graft patency and infection rates equal to autologous vein. Based on these studies, small intestinal submucosa was used as a biological wound dressing in 20 x 20 mm full-thickness wounds made on Sprague-Dawley rats. In the controls (group I, n = 12), an acrylic frame (20 x 20 mm) was sutured to the wound edges, followed by placement of a thin polyurethane film. In the small intestinal submucosa-treated animals (group II, n = 12), the wound was covered with small intestinal submucosa and then with the acrylic frame and polyurethane film. The wounds were examined both visually and histologically at postapplication days 3, 7, 14, 28, 42 and 56. In addition, the wound contraction rate of 6 animals in both groups were recorded at postapplication day 0 and then at 1 week, 1 month, 2 months, and 3 months. Histological analysis (hematoxylin-eosin and periodic acid-Schiff stains) of the small intestinal submucosa-treated wounds revealed no host-versus-graft rejection and a rate of epithelialization equal to that of the control group. The wound contraction rate was statistically significant (higher; p < .05) in the control group compared to the small intestinal submucosa-treated group. Porcine small intestinal submucosa merits further study as both a biological wound dressing and as a substrate for cultured cells.

Focal cemento-osseous dysplasia: a clinicopathologic study of 221 cases.

Classification of cemento-osseous lesions of the jaws has long been a dilemma for pathologists. A group of 221 cemento-osseous lesions exhibited sufficiently distinctive clinicopathologic features to be separated into a specific category: focal cemento-osseous dysplasia. This entity presents as an asymptomatic, focal, mixed radiolucent/radiopaque lesion with ill-defined borders in the tooth-bearing areas. It was found to occur with greater frequency in women (88%) and in the posterior mandible (77%). The average age at presentation was 37 years and a relative predilection for black patients was observed. At surgery these lesions were noted to be hemorrhagic, gritty, and adherent to the surrounding bone. The gross appearance of multiple hemorrhagic fragments is of diagnostic significance. Histologic features include a cellular connective tissue stroma punctuated by irregular osseous and/or cementum-like calcifications. Focal cemento-osseous dysplasia is thought to be of periodontal ligament origin and to be non-neoplastic in nature. Further surgical intervention is not necessary, but periodic follow-up is recommended, because occasional cases were observed to progress into florid osseous dysplasia. Care must be taken to differentiate focal cemento-osseous dysplasia from central cementifying and/or ossifying fibromas, which are true neoplasms and require surgical treatment.

A potential biomaterial composite for dermal and subcutaneous augmentation.

Based on previous experimental connective tissue work in cutaneous wound healing, cell culture, and fat transplantation, the use of positively charged dextran beads for subcutaneous and dermal augmentation was evaluated. When combined with a biocompatible liquid medium, the material easily flowed through small-gauge needles. When injected beneath the facial skin in rats, a profound macrophage response was initially seen at 30 days accompanied by fibroblast proliferation and new collagen formation. By 1 year, a quiescent noninflammatory cellular response with extensive intermaterial collagen deposition was evident. No adverse reactions were seen in the contralateral facial sites, which were injected with only the liquid medium. These preliminary findings suggest good tissue compatibility of this composite biomaterial and provide further evidence of the significant regulatory role of the macrophage in the tissue response to implanted biomaterials.

Effects of a positively charged biomaterial for dermal and subcutaneous augmentation.

Based on previous experimental connective tissue work, the use of a positively charged dextran-based biomaterial in subcutaneous tissue sites was evaluated. After hydration with saline, the biomaterial was injected beneath the abdominal skin in rats. A robust macrophage response was initially seen at 30 days without acute inflammation. By one year postoperatively, extensive intermaterial fibroblast and collagen ingrowth had occurred. No evidence of a foreign-body or chronic inflammatory response was seen. These preliminary findings suggest good tissue compatibility of this biomaterial and suggests that when combined with a biocompatible liquid medium, the potential for development of a bioactive dermal and subcutaneous injectable substance exists.

Histologic effects of smokeless tobacco and alcohol on the pouch mucosa and organs of the Syrian hamster.

This study's intent was to measure the histologic effects of smokeless tobacco and alcohol on the buccal pouch mucosa and internal organs of male Syrian hamsters. Eighty hamsters were divided into four groups: tobacco only, alcohol only, tobacco and alcohol, and negative control. 200 mg of smokeless tobacco were placed in each pouch of the tobacco groups five times a week. In the alcohol groups, 2 ml of 15% ethyl alcohol were placed in each pouch five times a week. The negative control group had mechanical stimulation of the right pouch to simulate the placement of the tobacco. After 26 wk the animals were sacrificed with pouches and abdominal organs removed. Alterations were observed in the abdominal organs, but not of statistical significance. However, significant acanthosis of the pouch epithelium was noted in the tobacco and tobacco and alcohol groups. This study reaffirms the lack of carcinogenic potential of smokeless tobacco upon the hamster pouch mucosa and internal organs.

Oral squamous cell carcinoma in Indiana.

Oral cancer is expected to occur in 30,800 individuals in the United States in 1991. This article describes the clinical features of 549 cases which were submitted to the Indiana University School of Dentistry Department of Oral Pathology Biopsy Service for the years 1985-1990. Women accounted for 43.8 percent of the cases, and the average age at detection was 62.7. The tongue and floor of the mouth were the sites of origin of 49.6 percent of the cases. The duration of the carcinomas was six months or less in 77.4 percent of the cases. Symptoms were observed in 73.6 percent of the cases and 66 percent were less than 2 cm. in size. Nodes were palpable in 21.4 percent of the cases in which it was specified. This study supports the observation of an increasing incidence of oral cancer in women, as well as in the most common sites of origin, the tongue and floor of the mouth.