A study is made of the utility of magnetic resonance imaging (MRI) in the diagnosis of benign pleomorphic adenomas of the parotid gland. Eighteen patients with parotid pleomorphic adenomas were studied using a 0.5T superconducting magnet; acquisitions were made with Spin Echo (SE) T1W axial and coronal sequences and SE T2W axial sequences (slice thickness 5 mm). A histopathological diagnosis was subsequently established in each case. MRI showed homogeneous images of low to intermediate signal intensity in SE T1W sequences, and high intensity signals with SE T2W sequences, allowing identification of the tumor mass and its intraglandular (facial nerve) and extraglandular relations (skull base and neck). All cases were confirmed histopathologically. MRI is presently the imaging diagnostic tool of choice in the study of parotid gland pleomorphic adenomas.
Key words: Magnetic resonance imaging. Pleomorphic adenoma. Imaging diagnosis. Mixed tumor.

Vera Sempere FJ, Navarro Hervás M. P53 suppressor gene overexpression in oral cancer. Medicina Oral 1997;2: 283-96.

SUMMARY

The p53 suppressor gene is one of the genes most commonly implicated in tumor genesis. p53 mutations have been described in over 50% of all human neoplasms. Under normal conditions, this gene exerts a negative regulatory influence upon cell proliferation. The mechanism involved is complex, for at the same time it functions as a transcription factor, cell cycle interruptor and inducer of apoptosis. p53 mutations may involve different molecular mechanisms. In this sense, immunohistochemical analysis of mutant p53 protein expression appears to constitute an indirect approach for the analysis of such mutations. However, different non-mutational actions including interactions with viral oncoproteins might stabilize the protein or functionally inactivate it. Consequently, analyses involving different molecular strategies (SSCP and cDNA nucleotide sequencing) could provide information complementary to that derived from immunohistochemical studies. Immunohistochemical expression of p53 has been reported in 11-73% of all squamous cell carcinomas of the oral cavity, with a nuclear labeling pattern related to the degree of tumor differentiation, cellular atypia and the level of in-depth infiltration. Controversy exists over the prognostic value of p53 overexpression in oral cancer, at least as an independent prognostic parameter. However, interest in this oncoprotein centers on its application to the biopsy diagnosis of precancerous or potentially malignant lesions, since the appearance of p53 mutations probably constitutes a very early event in oral carcinogenesis - often in association with tobacco smoking.
Key words: p53 gene. Immunohistochemistry. Oral cancer.

Silvestre FJ, Verdú MJ, Grau D. Prevention of bacterial endocarditis in dentistry. An update. Medicina Oral 1997;2:297-300.

SUMMARY

A presentation is made of the latest recommendations for the prevention of bacterial endocarditis in dental management. Special emphasis is placed on the 1997 recommendations of the American Heart Association, where oral amoxicillin is indicated as the drug of choice in both adults (2g 1h before intervention) and children (50 mg/kg 1 h before intervention). In patients with allergy to penicillins, the recommendations are clindamycin (600 mg 1 h before in adults, 20 mg/kg 1 h before in children), cefalexin (2g 1 h before in adults, 50 mg/kg 1 h before in children), and azithromycin or clarithromycin (500 mg 1 h before in adults, 15 mg/kg 1 h before in children).
Key words: Bacterial endocarditis. Prevention. Odontology.

De Vicente JC, Alonso D, Junquera LM, Santamaría J, Ferreras J, Madrigal B. Pleomorfic adenoma arising in heterotopic salivary gland tisue . Medicina Oral 1997;2: 301-8.

SUMMARY

Heterotopic salivary tumors in the neck and chest are rare. Salivary gland tissue located in sites different than those appropriate for normal anatomic distribution of the major and minor salivary glands is referred to as heterotopic (ectopic or choristoma) salivary gland tissue. Its embryogenesis is often unclear and is related to the anatomic site. The majority of heterotopic salivary gland tissue ha been seen to occur in the head and neck, but such tissue also has been found in remote areas of the body. Salivary gland tumors occasionally arise over this ectopic tissue. The majority of them are of the mucoepidermoid type. Other types found are: mixed tumor, Warthin´s tumor and other adenomas. Two patients with heterotopic salivary pleomorfic adenomas are presented. Local complete excision was successful. The literature concerning salivary heterotopias and salivary tumors arising from heterotopic salivary tissue is also reviewed. The embryologic basis for such finding and its clinical characteristics are discussed.
Key words: Heterotopic salivary tissue, heterotopic pleomorfic adenoma.

Camps M, Bagán JV, Cardona F, Lloria de Miguel E, Jiménez Y. Non-Hodgkin´s lymphoma presenting as an oral ulceration in an HIV negative patient. Medicina Oral 1997;2:309-14.

SUMMARY

We present a case of a non-Hodgkin´s lymphoma in an HIV negative patient in wich an oral ulceration was the only manifestation of the malignant disease. Treatment consisted of chemotherapy following a CHOP scheme, and a 40-Gray dose radiotherapy, after which the patient experienced a resolution of the initial lesion. As this disorder can be easily confused with other lesions in the oral cavity, it is important to highlight the need for an early diagnosis.
Key words: Non-Hodgkin´s lymphoma, oral.

Rodado C, González J, Huguet P, Ávila M, Raspall G. Lung adenocarcinoma presenting as an oral metastasis. Medicina Oral 1997;2:315-20.

SUMMARY

Most carcinomas diagnosed in the oral cavity and in the maxillary bones have their primary origin in the orofacial area, being the metastasis an unfrequent event. Even though that lung and breast neoplasms are the most frequent to metastatize, any malignancy can lead to oral metastasis. There are no pathognomonic signs or symptoms of a metastatic lesion, and they can appear in any moment of the natural history of the primary neoplasm. Both treatment and prognosis of these patients rely on theevolution of the general disease. Diagnosing an oral metastasis suggests an advanced stage of the disease, being a sign of poor prognosis. We present a case of lung adenocarcinoma whose first sign was a soft tissues mass in the lower jaw alveolar crest.
Keywords: Metastasis, Jawbones, Oral cancer.

Subscription to Medicina Oral

VOLUME 2. NUMBER 5. 1997