The fact that the identity of the cells that initiate metastasis in most human cancers is unknown hampers the development of antimetastatic therapies. Here we describe a subpopulation of CD44 cells in human oral carcinomas that do not overexpress mesenchymal genes, are slow-cycling, express high levels of the fatty acid receptor CD36 and lipid metabolism genes, and are unique in their ability to initiate metastasis. Palmitic acid or a high-fat diet specifically boosts the metastatic potential of CD36 metastasis-initiating cells in a CD36-dependent manner. The use of neutralizing antibodies to block CD36 causes almost complete inhibition of metastasis in immunodeficient or immunocompetent orthotopic mouse models of human oral cancer, with no side effects. Clinically, the presence of CD36 metastasis-initiating cells correlates with a poor prognosis for numerous types of carcinomas, and inhibition of CD36 also impairs metastasis, at least in human melanoma- and breast cancer-derived tumours. Together, our results indicate that metastasis-initiating cells particularly rely on dietary lipids to promote metastasis.

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a b s t r a c tThe use of CO 2 laser has become a routine procedure for the treatment of oral leukoplakia. In this retrospective study, we evaluated 65 patients with oral leukoplakia treated with CO 2 laser vaporization. The main location was the tongue (n ¼ 21/65, 32.3%). The initial biopsy showed mild/moderate dysplasia in almost half the patients (n ¼ 29, 44.6%) and hyperplasia without dysplasia in around a third of the patients (n ¼ 21, 32.3%). The recurrence and malignant transformation rates were 33.8% (n ¼ 22) and 15.4% (n ¼ 10), respectively. The follow-up mean (standard deviation) was 15.0 (10.6) months. The procedure-related complications rate was 7.7% (n ¼ 5). The KaplaneMeier curves for time to recurrence showed differences only for gingiva lesions compared to tongue lesions (log rank, p ¼ 0.032). Malignant leukoplakia transformation is independent of treatment, although it seems advisable to treat leukoplakia with or without dysplasia.

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a b s t r a c tWe conducted a systematic review of the literature to evaluate treatment of oral leukoplakia with the carbon dioxide (CO 2 ) laser.A comprehensive search of studies published between 1981 and 2015 and listed in the PubMed (National Library of Medicine, NCBI) database yielded 378 articles which were screened in detail. Relevant studies were selected according to predetermined inclusion and exclusion criteria. A total of 33 articles met the final inclusion criteria and were analysed in detail in accordance with the PRISMA-P statement. These full-text papers were classified as synopses (n ¼ 7), recurrence and malignant transformation studies (n ¼ 17), comparative studies between CO 2 laser and cold knife surgery (n ¼ 3) and studies evaluating the efficacy of CO 2 , Nd:YAG and KTP lasers.According to the literature the CO 2 laser is the workhorse of oral leukoplakia treatment due to its effectiveness and low associated morbidity. However, randomized clinical trials are needed to compare CO 2 laser with other lasers. The results of our systematic review showed that there is no consensus regarding the factors involved in higher recurrence and malignization rates, so further studies are needed.

BackgroundMyositis Ossificans is a rare heterotopic bone formation within a muscle being the masticatory muscles exceptionally involved. In most cases there is a previous trauma, bearing in mind that there may be many other etiologies. CT scan and panoramic radiographs along with histological findings are essential diagnostic aids.Case DesciptionWe report a rare case of MO of masseter muscle in 49 years-old woman after repetitive wisdom tooth infection with the discussion of clinical, radiological and histological features.Clinical ImplicationsMO is a rare disease of masticatory muscles being the masseter the most frequently affected. Wide surgical excision with free margins is the treatment of choice although close postoperative monitoring it’s essential to avoid relapses. Key words:Myositis ossificans, myositis ossificans traumatica, masticatory muscles, masseter muscle, trauma.

Oral squamous cell carcinoma (OSCC) is a very aggressive cancer, representing one of the most common malignancies worldwide. Oral potentially malignant disorders (OPMDs) regroup a variegate set of different histological lesions, characterized by the potential capacity to transform in OSCC. Most of the risk factors associated with OSCC are present also in OPMDs’ development; however, the molecular mechanisms and steps of malignant transformation are still unknown. Treatment of OSCC, including surgery, systemic therapy and radiotherapy (alone or in combination), has suffered a dramatic change in last years, especially with the introduction of immunotherapy. However, most cases are diagnosed during the advanced stage of the disease, decreasing drastically the survival rate of the patients. Hence, early diagnosis of premalignant conditions (OPMDs) is a priority in oral cancer, as well as a massive education about risk factors, the understanding of mechanisms involved in malignant progression and the development of specific and more efficient therapies. The aim of this article is to review epidemiological, clinical, morphological and molecular features of OPMDs, with the purpose to lay the foundation for an exhaustive comprehension of these lesions and their ability of malignant transformation and for the development of more effective and personalized treatments.

Objectives: Ghost cell odontogenic carcinoma is a rare condition characterized by ameloblastic-like islands of epithelial cells with aberrant keratinitation in the form of Ghost cell with varying amounts of dysplastic dentina. Material and Methods: We report a case of a 70 year-old woman with a rapid onset of painful swelling right maxillary tumor. Magnetic resonance showed a huge tumor dependent on the right half of the right hard palate with invasion of the pterygoid process and focally to the second branch of the trigeminal. Radiological stage was T4N0. The patient underwent a right subtotal maxillectomy with clear margins. Adjuvant radiotherapy was given. The patient was free of residual or recurrent disease 12 months after surgery. Results: The tumor was 3,9cm in diameter. It was spongy and whitish gray. Microscopically the tumor was arranged in nets and trabeculae, occasionally forming palisade. Tumoral cells had clear cytoplasm with vesicular nuclei. There was atipia and mitosi with vascular and perineural invasion. The excised tumor was diagnosed as a GCOC. Conclusions: Ghost cell carcinoma is a rare odontogenic carcinoma. Its course is unpredictable, ranging from locally invasive tumors of slow growth to highly aggressive and infiltrative ones. Wide surgical excision with clean margins is the treatment of choice although its combination with postoperative radiation therapy, with or without chemotherapy, remains controversial. Key words:Ameloblastic carcinoma, calcifying odontogenic cyst, Ghost cell carcinoma, keratinizing epithelial odontogenic cyst, maxillary tumor, odontogenic carcinoma.