Multicentric peripheral ossifying fibroma

Peripheral ossifying fibroma (POF) is a common solitary gingival growth thought to arise from the periodontal ligament. Though the etiology of POF remains unknown, some investigators consider it an inflammatory or reactive process, while others suggest it is a neoplastic process. In this report, we present and discuss a unique case of multicentric POF, affecting the maxillary and mandibular gingiva of a 49-year-old Caucasian female with meticulous oral hygiene and routine dental care. Though biopsy samples from multiple sites revealed similar histopathologic features, consistent with POF, the fact that there was a multicentric presentation is a unique phenomenon for this lesion. Multicentric lesions presenting in the oral and maxillofacial region are not typical, but have been observed in conditions associated with known genetic mutations, such as nevoid basal cell carcinoma syndrome (multiple odontogenic keratocysts), multiple endocrine neoplasia type II (multiple neuromas), neurofibromatosis (multiple neurofibromas) and Gardner syndrome (multiple neoplasms). This case is the first one to demonstrate that there may be a multicentric variant of POF that has not been previously recognized, and given the clinical presentation and multifocal nature of disease, the lesions in this patient are likely the result of genetic mutation(s) that predisposes to gingival soft tissue overgrowths containing mineralized product.

Peripheral odontogenic tumor: a clinicopathologic study of 30 cases. General features and hamartomatous lesions

BACKGROUND

Peripheral odontogenic tumors (POT), either neoplastic or hamartomatous, are rare. This study briefly summarizes the general features of POT and selectively reviews the histomorphologic spectrum of under-recognized hamartomatous lesions that we have designated peripheral odontogenic hamartomas (POH) in order to shed more light into the pathogenesis of POT.

METHODS

Archival material accessioned at our institutions between 1970 and 2004 was systematically searched to identify examples of POT/POH.

RESULTS

Among 39 660 biopsies, we retrieved 25 cases of 'classical' POT and five cases of 'unique' POH. Odontogenic fibroma and ameloblastoma were by far the most common. Of POH, two purely epithelial lesions showed multiple strands of basaloid rests [odontogenic gingival epithelial hamartoma (OGEH)] and a conglomerate of polyhedral epithelium, ghost cells and concentric calcifications (calcifying epithelial odontogenic tumor-like hamartoma), respectively. OGEH and peripheral squamous odontogenic tumor (PSOT) deserve to be a related entity. In two types of mixed POH, ectomesenchymal elements appeared juxtaposed to the squamous lining (gingival cyst-like organoid hamartoma) and ghost cells aggregated in the enamel organ of a microdont (peripheral odontoma). None of POH exhibited continuity with the surface epithelium.

CONCLUSION

On the basis of this relatively limited series of cases, POH, to conceptualize a unified histogenetic source, are speculated to arise from the soft-tissue remnants of dental lamina. Gingival rests of Serres seem to retain the ability to pursue epithelial-ectomesenchymal interactions that are necessary leading to odontoma formation.

New proposal for T classification of gingival carcinomas arising in the maxilla

When the current T classification of the UICC (1987 and 1997) is used to stage carcinomas arising the upper alveolus and gingival and hard palate, most cases are classified as T4 because of their anatomic characteristics, similar to carcinomas arising in the lower alveolus and gingiva. This study compared the following two methods for classifying the T stage of maxillary carcinomas: (1) the original T classification criteria proposed by the UICC (1987 and 1997), and (2) a new T classification criteria, called the sinus and nasal floor (SNF) criteria. We found that the SNF criteria were more closely related to tumor control and survival than were the UICC criteria in patients with carcinomas arising in the upper alveolus and gingival and hard palate. Increased use of the SNF criteria is expected to improve staging of gingival tumors arising in the maxilla and increase the accuracy of diagnosis, especially of T4 tumors.

Aggressive, multifocal oral verrucous leukoplakia: proliferative verrucous leukoplakia or not?

BACKGROUND

Some oral verrucal lesions may constitute parts of the clinicopathological spectrum of proliferative verrucous leukoplakia (PVL). Because of its idiopathic yet sinister nature, it is possible that PVL may exist in other populations. The aim of this study was to review the clinicopathological features of persistent, multifocal, oral verrucal lesions in Malaysian population.

METHODS

Patients with multifocal oral verrucal lesions were selected from surgical and histopathological records.

RESULTS

Nine patients of diverse ethnicity with 43 biopsies were reviewed. The mean age at the presentation was 62 years. The most frequent sites affected were gum, sulci, cheek and tongue. Indulgence in risk habits was reported in about 70% of patients. Four cases developed multifocal carcinoma from multifocal leukoplakia.

CONCLUSIONS

In retrospect, none of the cases fulfilled the original PVL criteria, although three cases were suggestive of PVL. Nevertheless, these findings do not necessarily preclude the existence of PVL as a clinicopathological entity in Malaysian population.

Evaluation of T-classifications of upper gingival and hard palate carcinomas--a proposition for new criterion of T4

Most carcinomas of upper gingiva and hard palate are classified as T4 stage on the basis of the UICC criteria, since they easily invade the underlying bone tissue. We classified 43 patients with squamous cell carcinoma of the upper gingiva in terms of three criteria: (1) the original T-classification by UICC, (2) the classification by the Japan Society for Head and Neck Cancer (JSHNC), and (3) a new classification in which the maxillary sinus or nasal floor is used as the defining borderline for T4 (MSF classification). Our study demonstrated that the new classification was superior with regard to distribution of patients by T stage, correlation with prognosis and choice of treatment method.

Plasmablastic lymphomas of the oral cavity: a new entity associated with the human immunodeficiency virus infection

We report here a series of 16 highly malignant diffuse large B-cell lymphomas of the oral cavity with unique immunohistologic features. Fifteen of these developed in human immunodeficiency virus-positive patients. All cases displayed morphologic features of diffuse large-cell lymphomas but strikingly differed from them in that they showed a minimal or absent expression of the leukocyte common antigen as well as of the B-cell antigen CD20. Instead, the tumor cells showed a constant reaction with the plasma cell characteristic antibody VS38c and a frequent reaction with the CD79a antibody. This, in conjunction with a variable expression of cytoplasmic Ig and a monoclonal rearrangement of the Ig heavy chain gene in all of the three tested cases confirmed the B-cell nature, the clonal origin, and the plasmacellular differentiation of these neoplasms. The majority of these tumors were negative for the BCL-6 protein, with the remaining cases showing only a partial and weak expression of this antigen. An association with the Epstein-Barr virus (EBV) was found in 9 of 15 tested cases showing abundant EBV-encoded nuclear RNA transcripts in the absence of EBNA-2. Five of the EBV-positive cases variably expressed LMP-1. We propose to name these tumors plasmablastic lymphomas, in accordance with their morphologic and immunohistologic features. Knowledge of this lymphoma entity is important to avoid confusion with nonlymphoid malignancies due to the lack of commonly used lymphoid markers.

Mucosal condition of the oral cavity and sites of origin of squamous cell carcinoma

PURPOSE

This study investigated the clinical appearance of the affected mucosa in patients with squamous cell carcinoma (SCC) in the oral and oropharyngeal region.

PATIENTS AND METHODS

The mucosal conditions of 396 patients was classified into two types. Type A, showing ulcer formation and/or tumor formation, and type B, showing only mucosal enlargement without any other abnormality.

RESULTS

Type A was detected in the oral cavity and oropharynx, and type B was observed only in the upper and lower alveolus and gingiva. Of 14 type B patients histologically evaluated for the relationship between the tumor cells and surface oral epithelium, 10 showed a disconnection between the epithelium and the tumor cells, whereas in two the tumor cells extended into the epithelium.

CONCLUSION

It was concluded that SCC of type B is not of oral epithelial origin, but is of maxillary sinus epithelium or odontogenic cell origin. In the mandible, type B SCC originates from odontogenic epithelium (odontogenic carcinoma).

Peripheral adenomatoid odontogenic tumor: birth of a term

The terminology of adenomatoid odontogenic tumor had been reviewed and the different names for this lesion used over the course of time have been listed. A case of peripheral adenomatoid odontogenic tumor which occurred on the gingiva of the right maxillary central incisor of a 4-year-old girl is reported.

The histological nature of epulides in dogs

The histological characteristics of a series of 154 oral tumours with the clinical appearance of epulides in 129 dogs were reviewed. Diagnoses were based on current criteria in human oral pathology and compared with the original diagnoses. The histological findings suggested that the majority of epulides in the dog can be classified as focal fibrous hyperplasia (43.5 per cent), peripheral ameloblastoma (17.5 per cent), peripheral odontogenic fibroma (WHO type) (16.9 per cent) and pyogenic granuloma (1.95 per cent). In addition, a number of other odontogenic tumours (1.95 per cent) and non-odontogenic tumours (18.2 per cent) such as fibrosarcoma and squamous cell carcinoma, which are not traditionally associated with the clinical appearance of an epulis, were diagnosed. Of 74 lesions that were previously diagnosed as fibromatous and ossifying epulides, 50 (68 per cent) were reclassified as focal fibrous hyperplasia and 21 (28 per cent) as peripheral odontogenic fibroma (WHO type). The majority of lesions (76 per cent), which were originally classified as acanthomatous epulis, were found to be peripheral ameloblastoma. In addition, three squamous cell carcinomas, two rare odontogenic tumours and two cases of focal fibrous hyperplasia were diagnosed in this classification. It was concluded that, as in man, the term epulis is a clinically descriptive term and that the renal nature of these lesions should be determined histologically.

Classification and behaviour after surgery of canine 'epulides'

Seventy-five surgically excised canine gum neoplasms, which had previously been diagnosed as epulis or ameloblastoma, were reclassified on the basis of their presumed tissue of origin. They included 42 tumours of fibroblastic origin, which contained small foci of odontogenic epithelium and were classified as peripheral odontogenic fibroma, whilst 31 epithelial tumours were classified as basal cell carcinomas arising from the gum epithelium. Two epithelial tumours which apparently arose within the bone of the mandible and were not connected with the surface mucosa were classified as ameloblastomas. Follow-up studies after surgery revealed a recurrence rate of 17 per cent for the odontogenic fibromas and 50 per cent for basal cell carcinomas. Neither of the ameloblastomas, which were initially treated by radical excision, recurred locally and no metastases were detected from any of these tumours.

Sources of error in the registration of oral cancer

The names of 102 patients with histologically confirmed squamous cell carcinoma of the oral cavity were checked against Cancer Registry data for the Trent Region. The study was carried out to determine the accuracy of site recording and the failure rate of registration. Although 94 of the patients were registered, 38 per cent of these were incorrectly coded with respect to site. The way in which such errors may occur is discussed and the procedure for registration of oral cancer is explained.

Malignant tumours of the oral cavity. A study of 177 cases

An unselected material of 177 patients with malignant tumours of the oral cavity is presented and classified according to the TNM system. A therapeutic classification based on the TNM system is proposed. The material is analyzed regarding the 5-year survival rate and the frequency of recurrences in different therapeutic groups.