Ronell Bologna-Molina

Comparison of the value of PCNA and Ki-67 as markers of cell proliferation in ameloblastic tumors

Objectives: The aim of this study was to compare among PCNAand Ki-67 as the most reliable immunohistochemical marker for evaluating cell proliferation in ameloblastic tumors. Study Design: Observational, retrospective, and descriptive study of a large series of ameloblastic tumors, composed of 161 ameloblastomas and four ameloblastic carcinomas, to determine and compare PCNA and Ki-67 expression using immunohistochemistry techniques. Results: When analyzing Ki-67 positivity, the desmoplastic ameloblastoma demonstrated a significantly lower proliferation rate (1.9%) compared with the solid/multicystic and unicystic ameloblastomas and ameloblastic carcinomas (p<0.05), whereas the ameloblastic carcinomas displayed a significantly higher rate compared with all of the other ameloblastomas (48.7%) (p<0.05). When analyzing cell proliferation with PCNA, we found significant differences only between the ameloblastic carcinomas (93.3%) and the desmoplastic ameloblastomas (p<0.05). When differences between the immunopositivity for PCNA and Ki-67 were compared, the percentages were higher for PCNA in all types of ameloblastomas and ameloblastic carcinomas. In all cases, the percentages were greater than 80%, whereas the immunopositivity for Ki-67 was significantly lower; for example, the ameloblastic carcinoma expressed the highest positivity and only reached 48.7%, compared to 93.3% when we used PCNA. Conclusions: In the present study, when we used the proliferation cell marker Ki-67, the percentages of positivity were more specific and varied among the different types of ameloblastomas, suggesting that Ki-67 is a more specific marker for the proliferation of ameloblastic tumor cells. Key words:Ameloblastomas, ameloblastic carcinoma, PCNA, Ki-67, cell proliferation markers.

An easy cell counting method for immunohistochemistry that does not use an image analysis program

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Papillary Thyroid Carcinoma: Differential Diagnosis and Prognostic Values of Its Different Variants: Review of the Literature

Papillary thyroid carcinoma is the most common thyroid malignancy, and has an excellent prognosis, even with cervical lymph node metastasis; however, histological variants are considered relevant, which may be associated with familial adenomatous polyposis and tumor aggressiveness. Histological features, such as vascular and/or lymphatic invasion, angiogenesis, multifocality, high cellular proliferation rate, neoplastic cell dissemination, and the histological varieties, are indicative of poor prognosis, together with associated clinical factors: age, sex, and tumor size.

Tumor-associated macrophages and angiogenesis: A statistical correlation that could reflect a critical relationship in ameloblastoma

Neoplasm growth is determined not only by the tumor cells themselves, but also by the tumor microenvironment. Increased densities of macrophages and activation of angiogenesis have been identified as common events in the progression of several neoplasms. Ameloblastoma is one of the most frequent odontogenic tumors and an excellent model for the study of neoplasm progression due to the different clinical variants that it exhibits. Here, by immunohistochemical studies using antibodies against CD68 and CD34, we evaluated the density of macrophages and microvessels associated to 45 paraffin-embedded ameloblastomas. In solid/multicystic ameloblastoma (SMA), we observed significantly higher densities of both macrophages and microvessels than in unicystic (UA) and desmoplastic (DA) ameloblastomas. Likewise, higher densities of macrophages and microvessels were found in UA than in DA. Furthermore, a predominance of intratumoral and peritumoral macrophage infiltrates was seen in SMA, while in UA, both macrophages and microvessels were also detected in the wall of the cysts. In contrast, DA had scant macrophages and microvessels, mainly situated distant from tumoral cells. In addition, a high correlation between macrophage and microvessel densities was observed in the samples (r=0.9623). Our results suggest that these two tumor microenvironmental elements could have an important role during ameloblastoma progression.

Total lower-eyelid reconstruction: Modified Fricke's cheek flap

The present work reviews a total lower-eyelid reconstruction technique that is currently not widely in use but which, in some cases, has proven to be of great utility in the field of reconstructive plastic surgery of the palpebral area. We performed an observational, longitudinal, descriptive and retrospective follow-up study. A total of 34 cases of non-melanoma skin cancer in which the lower eyelid was completely reconstructed using one flap taken from the cheek (modified Frickes cheek flap) were reviewed. The follow-up time for the patients ranged from several months to 5 years. Analysis was performed using the Pearsons chi-square statistical test in an effort to examine the association between the techniques range of functionality and aesthetic variables. Results were considered significant with a p<0.05. The functional result was regular for 91.2%, poor for 8.8% and excellent for 0% (p<0.05). The aesthetic result was regular for 88.2%, poor for 11.8% and excellent for 0% (p<0.05). The main complications were scleral exposure and temporary ocular chemosis. Frickes lower cheek flap is an easy-to-perform, important and often-necessary technique that, in some cases, has yielded positive functional and aesthetic results. This procedure is performed on an outpatient basis and is optimal for aged patients who present with skin cancer and who require total lower-eyelid reconstruction. The use of this technique is associated with a low complication rate and low morbidity.

Intravascular Papillary Endothelial Hyperplasia (Masson’s Tumor) of the Mouth – A Case Report

We report a rare case of intravascular papillary endothelial hyperplasia (IPEH) of the oral mucosa. This neoplasm, known as Masson’s tumor, is an unusual vascular lesion of proliferating endothelial cells. It is usually confined to the lumen of preexisting vessels or vascular malformations. The principal significance of IPEH is its microscopic resemblance to angiosarcoma and possible misdiagnosis as such. Achieving a correct diagnosis is essential to avoid subjecting a patient to unnecessarily aggressive therapy. For this reason, awareness of this lesion is very important for dermatologists and dentists. In this article, we discuss the clinical features, histopathological characteristics, and management of IPEH and review the pertinent literature.

Prognostic factors and treatment strategies for adult head and neck soft tissue sarcoma

Adult head and neck soft tissue sarcomas are rare and display a variety of histological types and clinical characteristics; they are also associated with a variety of mortality risks. The purpose of this study was to examine all patients treated at the Instituto Nacional de Cancerologia for head and neck sarcoma during a 5-year period. Fifty-one adult patients were examined and treated for head and neck sarcomas from 2004 to 2009. The 51 tumours were histologically re-evaluated by expert pathologists and classified as low, intermediate or high grade sarcomas. A multivariate analysis was performed to evaluate the surgical margins, histological grades, and clinical stages as prognostic factors for the disease. Adult head and neck soft tissue tumours are rare, and they are associated with poor prognosis for patients, especially at clinical stages III and IV. The average survival rate after 2 years is 45%, and most of these patients die because of disease progression and metastases.

Molecular markers of cell adhesion in ameloblastomas. An update.

Ameloblastoma is the most common odontogenic tumor of epithelial origin, and though it is of a benign nature, it frequently infiltrates the bone, has a high rate of recurrence and could potentially become malignant. Cellular adhesion potentially plays an important role in the manifestation of these characteristics and in the tumor biology of ameloblastomas. Losses of cell-cell and extracellular matrix adhesion and cohesion are among the first events that occur in the invasion and growth of tumors of epithelial origin. The present review includes a description of the molecules that are involved in cell adhesion as reported for various types of ameloblastomas and discusses the possible roles of these molecules in the biological behaviors of this odontogenic tumor. Knowledge of the complex mechanisms in which these molecules play a role is critical for the research and discovery of future therapeutic targets. Key words:Ameloblastoma, cellular adhesion, molecular markers, cell-cell adhesion, extracellular matrix-cell adhesion.

Association between Urine Fluoride and Dental Fluorosis as a Toxicity Factor in a Rural Community in the State of San Luis Potosi

Objective. The aim of this study is to investigate urine fluoride concentration as a toxicity factor in a rural community in the state of San Luis Potosi, Mexico. Materials and Methods. A sample of 111 children exposed to high concentrations of fluoride in drinking water (4.13 mg/L) was evaluated. Fluoride exposure was determined by measuring urine fluoride concentration using the potentiometric method with an ion selective electrode. The diagnosis of dental fluorosis was performed by clinical examination, and the severity of damage was determined using Deans index and the Thylstrup-Fejerskov (TF) index. Results. The range of exposure in the study population, evaluated through the fluoride content in urine, was 1.1 to 5.9 mg/L, with a mean of 3.14 ± 1.09 mg/L. Dental fluorosis was present in all subjects, of which 95% had severe cases. Higher urine fluoride levels and greater degrees of severity occurred in older children. Conclusions. The results show that dental fluorosis was determined by the presence of fluoride exposure finding a high positive correlation between the severity of fluorosis and urine fluoride concentration and the years of exposure suggested a cumulative effect.

Differential expression of glypican-1 in ameloblastoma variants.

Although benign, ameloblastomas are locally invasive and destructive tumors of the jawbones. The glypicans comprise a family of glycosylphosphatidylinositol-anchored proteoglycans that, by virtue of their cell-surface localization and heparin sulfate chain composition, might regulate the response of cells to numerous heparin-binding growth factors, cell adhesion molecules, and extracellular matrix components. The expression of glypican-1 is differentially altered among different types of malignancies, suggesting a possible role in the tumorigenesis and biological behavior of these neoplasms. The aim of this study was to determine the expression of glypican-1 and then hypothesize the possible role that this protein may play in the biological behavior of ameloblastomas. We assessed the presence of glypican-1 by immunohistochemical staining analyses in a series of 80 cases of different types of ameloblastomas. Desmoplastic ameloblastomas exhibited the highest expression of glypican-1 (100%), followed by the peripheral (66%), solid/multicystic (51.2%), and unicystic (47.2%) types, showing statistically significant differences among them (P<0.001). Differences detected in glypican-1 expression among different subtypes of ameloblastomas, could be suggesting a possible association with their different biological behavior.