The Retromolar Trigone: Anatomy, Cancer Treatment Modalities, Reconstruction, and a Classification System.

BACKGROUND: Retromolar trigone (RMT) tumors are rare and aggressive malignancies, spreading rapidly into surrounding structures. In reviewing the literature, there is lack of information and quality evidence pertaining to their management and high heterogeneity in treatment modalities. METHODS: A systematic Medline search was performed to gather all reports of articles related to retromolar trigone in tle last 10 years (2005-2015). Papers were excluded if they were related to oral cavity cancer but not specific for the RMT. RESULTS: Results were divided into 5 sections: anatomy and lymphatic drainage; etiology and diagnosis; cancer treatment modalities; reconstructive options; proposal of a classifications system. A clinical patient exemplification was also included. Various treatment modalities have been tried in the past including surgery, radiotherapy, and combination therapy using chemoradiation. All these modalities have intrinsic risks. There is also controversy regarding the extent of surgery. Reconstructive options differ with the size of the defects. The ability of the propeller lingual flap to rotate any angle up to 180 degrees allows it to reconstruct small-to-medium sized defects. If bulkier reconstructions are needed to separate oral and nasal cavities, a free flap (radial forearm, anterolateral thigh, medial sural) should be planned. CONCLUSIONS: In view of the rarity of the tumor and heterogeneity of treatment, there is limited information available pertaining to retromolar trigone tumors. A better understanding of RMT amatomy, cancer treatment modalities, and reconstructive options can improve the surgeon decision capacity and clinical results, when dealing with such uncommon and challenging tumors.

[Principles and therapeutic elements of lesions of the oral mucosa]. / Principes et éléments thérapeutiques des lésions de la muqueuse orale.

The management of lesions of the oral mucosa requires precise knowledges and expertise in clinical care. This review article summarise the principles of the most validated therapeutical features about lesions of the oral mucosa. Global management procedures are described. Therapeutic modalities involving drugs, surgery, radiotherapy, chemotherapy, immunotherapy, electrotherapy, gene therapy and photodynamic therapy are detailed as well.

Oral mucosal lesions associated with betel quid, areca nut and tobacco chewing habits: consensus from a workshop held in Kuala Lumpur, Malaysia, November 25-27, 1996.

A variety of betel/areca nut/tobacco habits have been reviewed and categorized because of their possible causal association with oral cancer and various oral precancerous lesions and conditions, and on account of their widespread occurrence in different parts of the world. At a recent workshop in Kuala Lumpur it was recommended that "quid" be defined as "a substance, or mixture of substances, placed in the mouth or chewed and remaining in contact with the mucosa, usually containing one or both of the two basic ingredients, tobacco and/or areca nut, in raw or any manufactured or processed form." Clear delineations on contents of the quid (areca nut quid, tobacco quid, and tobacco and areca nut quid) are recommended as absolute criteria with finer subdivisions to be added if necessary. The betel quid refers to any quid wrapped in betel leaf and is therefore a specific variety of quid. The workshop proposed that quid-related lesions should be categorized conceptually into two categories: first, those that are diffusely outlined and second, those localized at the site where a quid is regularly placed. Additional or expanded criteria and guidelines were proposed to define, describe or identify lesions such as chewer's mucosa, areca nut chewer's lesion, oral submucous fibrosis and other quid-related lesions. A new clinical entity, betel-quid lichenoid lesion, was also proposed to describe an oral lichen planus-like lesion associated with the betel quid habit.

Co-overexpression of p53 and c-myc proteins linked with advanced stages of betel- and tobacco-related oral squamous cell carcinomas from eastern India.

Epidemiological evidence suggests that heavy consumption of betel quid and tobacco with areca nuts is the cause of high incidence of oral cancer in eastern part of Indian population, which is distinctly different from the etiology of oral squamous cell carcinomas (SCCs) in western countries. Here, expression of p53 and c-myc protein was studied in oral SCCs from this etiologically distinct population by immunohistochemistry. Out of 48 specimens of oral SCCs, 22 (45.8%) exhibited p53 positivity and 27 (56.3%) showed immunoreactivity with c-myc antibody. Considering the p53/c-myc expression pattern, either alone or in combination, the population was divided into four groups, i.e., both p53 and c-myc positive; p53 positive-c-myc negative; c-myc positive - p53 negative; and both p53 and c-myc negative. Tumours with both p53 and c-myc positivity were in advanced stages of the disease (poorly differentiated, tumour stage 3, nuclear grade III), whereas earliest stage of oral SCCs was detected in tumours with neither p53 nor c-myc immunoreactivity. Tumours of remaining two groups were generally restricted to early to moderate stages. These observations suggest that rapid progression of the betel- and tobacco-related oral SCCs may be associated with a simultaneous involvement of these two oncoproteins. The study also attempted to find out the relationship of p53/c-myc expression with spontaneous apoptosis. More apoptotic cells were found in c-myc positive but p53 negative tumours. This preliminary observation requires further molecular investigation of the role of p53 and c-myc genes for the progression of this epidemiologically distinct oral carcinogenesis.

Expression of hMSH2 correlates with in vitro chemosensitivity to CDDP cytotoxicity in oral and oropharyngeal carcinoma.

We investigated the expression of hMSH2, a human mutS homologue from chromosome 2p, in oral and oropharyngeal squamous cell carcinoma (SCC) by an immunohistochemical technique and performed tumor in vitro chemosensitivity testing. In 58 oral and oropharyngeal SCC, the hMSH2 positive score was inversely associated with tumor size, but not with other clinical parameters. Among five anticancer drugs (cisplatin (CDDP), 5-FU, peplomycin, mitomycin C and doxorubicin), only for CDDP was sensitivity to cytotoxicity correlated with the hMSH2 positive score. The susceptibility of hMSH2-positive tumors to CDDP killing was significantly higher than that of hMSH2-negative tumors. Immunohistochemical results regarding hMSH2 are promising in the evaluation of the sensitivity of cancer cells to CDDP cytotoxicity and enable one to select patients for adjuvant chemotherapy for oral and oropharyngeal SCC.