Angela C. Chi

Odontogenic Cysts and Tumors.

This article presents various odontogenic cysts and tumors, including periapical cysts, dentigerous cysts, odontogenic keratocysts, orthokeratinized odontogenic cysts, lateral periodontal cysts, glandular odontogenic cysts, ameloblastomas, clear cell odontogenic carcinomas, adenomatoid odontogenic tumors, calcifying epithelial odontogenic tumors, squamous odontogenic tumors, ameloblastic fibromas, ameloblastic fibro-odontomas, odontomas, calcifying cystic odontogenic tumors, and odontogenic myxomas. The authors provide an overview of these cysts and tumors, with microsopic features, gross features, differential diagnosis, prognosis, and potential diagnostic pitfalls.

Implication of RNA-Binding Protein La in Proliferation, Migration and Invasion of Lymph Node-Metastasized Hypopharyngeal SCC Cells

The 5-year survival rate for oral cavity cancer is poorer than for breast, colon or prostate cancer, and has improved only slightly in the last three decades. Hence, new therapeutic strategies are urgently needed. Here we demonstrate by tissue micro array analysis for the first time that RNA-binding protein La is significantly overexpressed in oral squamous cell carcinoma (SCC). Within this study we therefore addressed the question whether siRNA-mediated depletion of the La protein may interfere with known tumor-promoting characteristics of head and neck SCC cells. Our studies demonstrate that the La protein promotes cell proliferation, migration and invasion of lymph node-metastasized hypopharyngeal SCC cells. We also reveal that La is required for the expression of β-catenin as well as matrix metalloproteinase type 2 (MMP-2) within these cells. Taken together these data suggest a so far unknown function of the RNA-binding protein La in promoting tumor progression of head and neck SCC.

Oral cavity and oropharyngeal squamous cell carcinoma—an update

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Oral Mucoceles: A Clinicopathologic Review of 1,824 Cases, Including Unusual Variants

PURPOSE To review the clinicopathologic features of oral mucoceles, with special consideration given to unusual variants and exclusion of salivary duct cysts. MATERIALS AND METHODS This was a retrospective consecutive case review of all oral mucoceles diagnosed by the Medical University of South Carolina, Oral Pathology Biopsy Laboratory, from 1997 to 2006. The following data were recorded: patient demographics, clinical features (anatomic location, color, size, and consistency), clinical impression, history of trauma, history of periodic rupture, and occurrence of unusual mucocele variants. RESULTS During the study period, 1,824 oral mucoceles were diagnosed. Of these cases, 1,715 represented histopathologically confirmed cases that were not recurrences. There was no significant gender predilection, and the average age was 24.9 years. The most common locations were the lower labial mucosa (81.9%), floor of mouth (5.8%), ventral tongue (5.0%), and buccal mucosa (4.8%); infrequent sites included the palate (1.3%) and retromolar area (0.5%). The lesions most often were described as blue/purple/gray or normal in color. The mean maximum diameter was 0.8 cm (range, 0.1 to 4.0 cm). In 456 cases, a history of trauma was reported, and in 366 cases a history of periodic rupture was reported. Unusual variants included superficial mucoceles (n = 3), mucoceles with myxoglobulosis (n = 6), and mucoceles with papillary synovial metaplasialike change (n = 2). CONCLUSIONS Our results confirm the findings of previous investigators regarding the major clinicopathologic features of oral mucoceles. Special variants of oral mucoceles occur infrequently, although it is important to recognize these variants to avoid misdiagnosis.

Oral premalignant lesions induce immune reactivity to both premalignant oral lesions and head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is an aggressive malignancy, and despite advances in treatments, the 5-year survival has remained at less than 50%. One treatment strategy is to focus on patients with premalignant oral lesions that carry a high-risk for developing recurrent premalignant lesions and HNSCC disease. As an initial attempt to determine if immune therapy has the potential to be protective in these patients, studies determined if premalignant lesions express tumor antigens that have previously been shown to be expressed on HNSCC. Immunohistochemical analyses showed prominent expression of epidermal growth factor receptor in premalignant lesions, even in lesions with mild dysplasia. MUC-1 and carcinoembryonic antigen were expressed in most patient samples, while NY-ESO-1 was less frequently expressed. Each of these antigens was expressed on HNSCC. This provided the rationale for determining if premalignant oral lesions could be used to stimulate autologous peripheral blood mononuclear leukocytes (PBML) to react against heterologous premalignant lesions and HNSCC. Following sensitization with autologous premalignant lesions, PBML responded to a challenge with either heterologous premalignant oral lesion cells or HNSCC by releasing IFN-γ. In addition, sensitization with autologous premalignant lesion lysates generated cytolytic activity by both PBML and T cells against allogeneic premalignant lesion cells and HNSCC. These studies show the feasibility of using premalignant oral lesions to stimulate immune reactivity against both premalignant oral lesions as well as HNSCC.

Epidermal Choristoma of the Oral Cavity: Report of 2 Cases of an Extremely Rare Entity

16 cases. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 101:304, 2006 8. Brookstone MS, Huvos AG: Central salivary gland tumors of the maxilla and mandible: A clinicopathological study of 11 cases with an analysis of the literature. J Oral Maxillofac Surg 50:229, 1992 9. Fernando M-M, Keyla P-D, Odele C, et al: Salivary gland tumors of the mandible. Ann Diagn Pathol 4:347, 2000 0. Kikuchi Y, Hirota M, Iwai T, et al: Salivary duct carcinoma in the mandible: A case report. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 103:41, 2007 1. Alexander RW, Depuis RH, Holten H: Central mucoepidermoid carcinoma of the mandible. J Oral Surg 32:541, 1974 2. Wang CC: Radiation Therapy for Head and Neck Neoplasms. Chicago, IL, Year Book Medical Publishers, 1990, p 327

Pseudomembranous disease (ligneous inflammation) of the female genital tract, peritoneum, gingiva, and paranasal sinuses associated with plasminogen deficiency.

Pseudomembranous disease (or ligneous inflammation) is a rare condition characterized by accumulations of fibrin-rich eosinophilic material. Recent investigations have linked the etiology of this condition to plasminogen deficiency (hypoplasminogenemia). Although much of the literature concerning this disease has focused upon the often clinically striking ocular manifestations, it is important to note that pathologic changes may develop in a variety of anatomic locations, including the oral cavity, upper and lower respiratory tract, female genital tract, kidneys, and gastrointestinal tract. Here, we report an unusual case of a 33-year-old woman who initially presented with gingival inflammation. In subsequent years, she developed additional signs and symptoms related to sinonasal and genital tract involvement. Despite numerous clinical evaluations, biopsies, and laboratory tests, the patients diagnosis remained elusive for 7 years. Ultimately, it was the distinctive appearance of the gingiva that led to a diagnosis of plasminogen deficiency. Unfortunately, the complicated clinical course and elapsed time between initial presentation and diagnosis illustrated by the present case are not uncommon among patients with this condition. Greater familiarity with the clinical and histopathologic features of this condition among pathologists and treating clinicians is essential for timely diagnosis and management.

Autocrine motility-stimulatory pathways of oral premalignant lesion cells

Patients with premalignant oral lesions have varying levels of risk of developing oral squamous cell carcinoma (OSCC), whose aggressiveness requires increased motility. Not known is if and how premalignant oral lesion cells acquire the increased motility characteristic of OSCC. This was addressed by immunohistochemical analysis of banked premalignant lesion tissues and by functional analyses using cultures established from premalignant oral lesions and OSCC. These studies showed premalignant oral lesion cells and OSCC to be more motile than normal keratinocytes. Concomitantly, levels of ceramide were reduced. The activity of the protein phosphatase PP-2A, which restricts motility and which can be activated by ceramide, was also diminished. This was due to IL-10 released from premalignant lesion cells. Treatment with a membrane-permeable ceramide restored PP-2A activity and blocked migration. These studies show an autocrine motility-stimulatory pathway that is mediated in premalignant lesion cells by IL-10 through its reduction of ceramide levels and inhibition of PP-2A activity.

Bone- and Cartilage-Forming Tumors and Ewing Sarcoma: An Update with a Gnathic Emphasis

Over the past decade, there have been remarkable advances in bone tumor pathology. Insights into the genetic basis and pathobiology of many tumor types have impacted diagnosis, classification, and treatment. However, because gnathic lesions may comprise only a small proportion of cases overall for many tumors, clinicopathologic features and management considerations specific to this subset may be overlooked. Here we provide a summary of recent developments in the following tumor types: osteosarcoma (OS), chondrosarcoma (CS), osteoid osteoma (OO), osteoblastoma (OB), and Ewing sarcoma (ES). In particular, we will give special consideration to cases arising in the jaws.

Electronic cigarette explosion: Case report of an emerging cause of orofacial trauma

Electronic cigarettes are a type of electronic nicotine delivery system. In the United States, electronic cigarettes have surged in popularity since their introduction to the market in 2007. Health and safety concerns primarily have focused on e-liquid/aerosol composition and whether these devices represent a gateway versus lower risk alternative to conventional cigarettes. Furthermore, recent incidents have demonstrated the potential for significant orofacial injury caused by device explosion while in use. Herein we report a case of a 20-year-old male who sustained oral burns, lacerations, and tooth loss when an electronic cigarette exploded in his mouth shortly after he charged the battery. Only seven other cases of trauma from intraoral electronic cigarette explosions have been reported in the scientific literature to date, although several similar incidents also have been reported by the news media. Treatment of such patients often requires a multidisciplinary approach. Design/manufacturing issues and improper handling may cause an increase in internal battery temperature. An investigation by the United States Fire Administration concluded that user education may aid in preventing some electronic cigarette explosions, and safety design improvements also could help. Although some studies and authorities support the use of electronic cigarettes for tobacco cessation and harm reduction, recent reports of electronic cigarette explosions raise important safety concerns and point to the need for further studies.