Specificity of paediatric jawbone lesions: tumours and pseudotumours.

INTRODUCTION: Characteristics and epidemiology of jaw tumours have been described mostly in adults. Compared with their adult counterparts, childhood jaw tumours show considerable differences. The aim of this study was to describe the different jaw tumours in children, define diagnostic tools to determine their specificity and describe optimal treatment. METHODS: All children patients with jaw lesions, excluding cysts, apical granuloma and osteitis were included in our study between 1999 and 2009. The medical records were analyzed for clinical, radiological, and pathological findings, treatments and recurrences. RESULTS: Mean patient age was 10.9 years old, ranging from 2 months to 18 years old. Of the 63 lesions, 18 were odontogenic and 45 non-odontogenic lesions. 6% of all cases were malignant tumours; the mean age of presentation was 7.25 years old, [ranging from 0.2 to 18 years old]. Approximately 80% of the tumours developed after 6 years of age. Odontogenic tumours occurred more often after the age of 6. CONCLUSION: Compared with their adult counterpart, childhood jaw tumours show considerable differences in their clinical behaviour and radiological and pathological characteristics. Clinical features of some tumours can be specific to children. Tumourigenesis is related to dental development and facial growth. Conservative treatment should be considered.

PTCH1 mutation and local aggressiveness of odontogenic keratocystic tumors in children: is there a relationship?

Keratocystic odontogenic tumors (KCOTs) are locally aggressive jaw lesions that may be related to PTCH1 mutations in isolation or in association with nevoid basal cell carcinoma syndrome. We sought to clarify the role of PTCH1 mutation in KCOT aggressiveness. We assessed cyst pathological characteristics, Ki-67 immunostaining, and somatic and germinal PTCH1 mutation in 16 KCOTs from 10 unrelated patients. Ten PTCH1 mutations were identified in 16 tumors. All tumors with PTCH1 mutations presented the criteria of pathological aggressiveness. We also noted the presence of a chorionic epithelial structure apparently acting as a secondary germinal center in these same tumors. Ki-67 immunostaining was not associated with PTCH1 mutation. KCOTs harboring the mutation display a chorionic epithelial structure that acts as a secondary germinal center. Genetic and microenvironmental factors might interact to propel tumor development.

Mandibular cuniculatum carcinoma: apropos of 3 cases and literature review.

BACKGROUND: Cuniculatum carcinoma is a well-differentiated form of squamous cell carcinoma that shares histologic characteristics with papillary squamous cell carcinoma and verrucous carcinoma. Cuniculatum carcinoma usually occurs on the plantar region, and only 16 cases involving the oral cavity have been described in the literature. METHODS: The authors have reported 3 cases of mandibular cuniculatum carcinoma. All of the patients were in a great deal of pain. Histologic diagnosis was difficult due to the presence of few cellular atypies. Clinical criteria, osseous lysis, and the coexistence of multiple intraosseous well-differentiated, hyperkeratotic papillomatous lesions with few cellular atypies sign the diagnosis. RESULTS: No local recurrence has been reported after treatment with radical surgery alone. CONCLUSION: The diagnosis is often delayed. Although cuniculatum carcinoma displays aggressive behavior locally, lymph node infiltration and metastasis are rare. The therapy of choice is surgical removal with free margins, after which the prognosis is excellent.

The effect of etidronate on the periodontium of ovariectomized rats.

BACKGROUND: Bisphosphonates are indicated for the treatment of osteoporosis. However, they could have an adverse effect on specific sites, such as the bisphosphonate-related osteonecrosis of the jaw. The aim of this study is to investigate the effect of etidronate on the resorption and apposition sides of the periodontium in ovariectomized rats. METHODS: Twenty-four female Wistar rats were randomly subjected to either ovariectomy or sham operation. After 8 weeks, six animals of each group were sacrificed. The other 12 rats received 5 mg/kg/day etidronate subcutaneously during 4 weeks. Tartrate-resistant acid phosphatase reaction and immunohistochemical staining for receptor activator of nuclear factor-κB (RANK), RANK-ligand (RANKL), osteoprotegerin (OPG), and osteocalcin was performed. Immunoreactivity was evaluated using a semiquantitative analysis. RESULTS: In ovariectomized rats, osteoclasts were noticed in the root socket of molars, including the apposition side of the periodontium, in which RANKL expression was significantly evidenced. In the etidronate-treated group, OPG expression was significantly expressed and osteoclasts that were noticed in the resorption side remained undetected in the apposition side even under ovariectomy. RANK was significantly expressed in ovariectomized rats treated with etidronate. Osteoid formation and osteocalcin expression were described on the alveolar bone surfaces in etidronate-treated rats, with or without ovariectomy. CONCLUSIONS: Etidronate has specific site and bone cell actions in the periodontium. It inhibits the osteoclast differentiation induced by ovariectomy in the apposition side of the periodontium but maintains bone formation over all the socket surfaces. Such specificity may be related to the pathogenesis of the bisphosphonate-induced osteonecrosis of the jaw.

A treatment algorithm for adult ameloblastomas according to the Pitié-Salpêtrière Hospital experience.

During a 13-year period (from 1994 to 2007), in the Oral and Maxillofacial Surgery Department of the Pitié-Salpêtrière Hospital, 116 new cases of adult ameloblastomas, were analyzed for treatment composed against radiographic presentation, size, histological type. Follow-up and recurrence were also analyzed. Treatment was surgical consisting of enucleations (82%), segmental mandibulectomy (8.3%) resections (24.7%) 85% of them underwent reconstruction. The follow-up was documented for 97%. More than two recurrences occurred in 21% of the patients after the first enucleation: 66% with a "follicular" histological diagnosis. Lenthly, a therapeutic algorithm is suggested for adult ameloblastomas that underlines the importance of the conservative enucleation treatment as far as possible.

Msx and dlx homeogene expression in epithelial odontogenic tumors.

Epithelial odontogenic tumors are rare jaw pathologies that raise clinical diagnosis and prognosis dilemmas notably between ameloblastomas and clear cell odontogenic carcinomas (CCOCs). In line with previous studies, the molecular determinants of tooth development-amelogenin, Msx1, Msx2, Dlx2, Dlx3, Bmp2, and Bmp4-were analyzed by RT-PCR, ISH, and immunolabeling in 12 recurrent ameloblastomas and in one case of CCOC. Although Msx1 expression imitates normal cell differentiation in these tumors, other genes showed a distinct pattern depending on the type of tumor and the tissue involved. In benign ameloblastomas, ISH localized Dlx3 transcripts and inconstantly detected Msx2 transcripts in epithelial cells. In the CCOC, ISH established a lack of both Dlx3 and Msx2 transcripts but allowed identification of the antisense transcript of Msx1, which imitates the same scheme of distribution between mesenchyme and epithelium as in the cup stage of tooth development. Furthermore, while exploring the expression pattern of signal molecules by RT-PCR, Bmp2 was shown to be completely inactivated in the CCOC and irregularly noticeable in ameloblastomas. Bmp4 was always expressed in all the tumors. Based on the established roles of Msx and Dlx transcription factors in dental cell fates, these data suggest that their altered expression is a proposed trail to explain the genesis and/or the progression of odontogenic tumors.

Histological features and management of a mandibular Gorham disease: a case report and review of maxillofacial cases in the literature.

Gorham disease (GD) is a rare osteolysis without sex, race, or age predilection, affecting bones in different regions. Based on clinical, histological, and molecular features, diagnosis is difficult and required exclusion of neoplastic, inflammatory, infectious, and endocrinologic disease. Etiology is still unknown. We report the case of a 36-year-old man suffering from severe progressive osteolysis located at the mandible. Histology showed massive osteolysis without malignant cells. Immunohistochemistry revealed thin-walled vessels and lymphatic ducts. These investigations lead to diagnosis of GD. Radical surgical treatment was followed by bisphophonate therapy. Recurrence occurred 4 months after surgery and alphaa-interferon therapy permitted remission. To support this case report, we reviewed the 41 maxillofacial cases published in the literature since 1928. Jaw is the main location; histology mostly shows hemangioma-like proliferation. Immune disorders are usually advanced as a cause although physiopathology is unknown. Therefore, appropriate treatment is controversial. Antiosteoclastic drugs are usually proposed in addition to surgery, but immunomodulating drugs and radiation therapy should also be considered in the treatment.