Oslei Paes de Almeida

International collaborative study on ghost cell odontogenic tumours: calcifying cystic odontogenic tumour, dentinogenic ghost cell tumour and ghost cell odontogenic carcinoma.

BACKGROUND Calcifying odontogenic cyst was described first by Gorlin et al. in 1962; since then several hundreds of cases had been reported. In 1981, Praetorius et al. proposed a widely used classification. Afterwards, several authors proposed different classifications and discussed its neoplastic potential. The 2005 WHO Classification of Odontogenic Tumours re-named this entity as calcifying cystic odontogenic tumour (CCOT) and defined the clinico-pathological features of the ghost cell odontogenic tumours, the CCOT, the dentinogenic ghost cell tumour (DGCT) and the ghost cell odontogenic carcinoma (GCOC). METHODS The aim of this paper was to review the clinical-pathological features of 122 CCOT, DGCT and GCOC cases retrieved from the files of the oral pathology laboratories from 14 institutions in Mexico, South Africa, Denmark, the USA, Brazil, Guatemala and Peru. It attempts to clarify and to group the clinico-pathological features of the analysed cases and to propose an objective, comprehensive and useful classification under the 2005 WHO classification guidelines. RESULTS CCOT cases were divided into four sub-types: (i) simple cystic; (ii) odontoma associated; (iii) ameloblastomatous proliferating; and (iv) CCOT associated with benign odontogenic tumours other than odontomas. DGCT was separated into a central aggressive DGCT and a peripheral non-aggressive counterpart. For GCOC, three variants were identified. The first reported cases of a recurrent peripheral CCOT and a multiple synchronous, CCOT are included. CONCLUSIONS Our results suggest that ghost cell odontogenic tumours comprise a heterogeneous group of neoplasms which need further studies to define more precisely their biological behaviour.

Hereditary gingival fibromatosis: Report of an extensive four-generation pedigree

A Brazilian family with hereditary gingival fibromatosis is described with multiple affected subjects in four generations. A total of 50 (48%), of 105 at-risk offspring in a family of 132 members were affected, consistent with an autosomal dominant mode of inheritance. This family appears to represent the largest pedigree with this condition reported in the literature.

Paracoccidioidomycosis of the Mouth: an Emerging Deep Mycosis

Oral fungal infections (mycoses) have come into particular prominence since the advent of infection with Human Immunodeficiency Virus (HIV), and recognition of the Acquired Immune Deficiency Syndrome (AIDS), as well as the phenomenal increase in world travel with increased exposure to infections endemic in the tropics. Paracoccidioidomycosis is a rare mycosis worldwide but common in Brazil and some other areas in Latin America. It can be life-threatening and can manifest with a spectrum of clinical presentations, including frequent oral lesions. This paper reviews the more recent information on Paracoccidioidomycosis, emphasizing those areas most relevant in dental science.

Syndecan-1 (CD138) and Ki-67 expression in different subtypes of ameloblastomas

Ameloblastoma is the most frequent odontogenic tumor and is considered a benign, but locally invasive, neoplasm with variable clinico-pathological expression. Syndecan-1 is a cell surface proteoglycan that binds cells to the extracellular matrix and its expression is down-regulated in many cellular transformation models. The aims of this study were to examine the pattern of syndecan-1 expression, to evaluate the proliferating activity in a large series of solid/multicystic (SA) and unicystic ameloblastomas (UA), and to study its possible correlation to their biological behavior. Immunohistochemical studies were performed for syndecan-1 (clone MI15) and Ki-67 (clone MIB-1) in 120 ameloblastomas (75 SA and 45 UA). The salient finding was that expression of syndecan-1 was related to the histological subtype of tumors, as there was a lower expression in SA (40.2%) as compared to UA (49.7%) (p<0.05). These findings did not correlate with Ki-67 expression, as this was similar in both types of ameloblastomas. Our results suggest that the reduced expression of syndecan-1 supports the view that SA has a more aggressive biological behavior than the UA. The lack of correlation between reduction of the syndecan-1 and Ki-67 index may be due to the different histomorphologies of both types of ameloblastoma, and more studies are necessary to better understand the role of this protein in the biological behavior of these tumors.

Basaloid squamous carcinoma of oral cavity: a histologic and immunohistochemical study

Basaloid squamous carcinoma (BSC) is an aggressive variant of squamous cell carcinoma (SCC) with a predilection for the upper aerodigestive tract. In the English literature, approximately 40 cases of BSC have been described in the oral cavity. BSC has frequently been confused with adenoid cystic carcinoma (ACC), basal cell adenocarcinoma, and undifferentiated SCC. The purpose of the investigation was to examine the histological features and immunohistochemical expression of differentiation-related substances, including cytokeratin (CK) subtypes, vimentin, S-100, chromogranin, laminin, and type IV collagen, for the characterization of biological features of these tumours. We studied three cases of BSC of the oral cavity, three cases of ACC, and one case of basal cell adenocarcinoma. Well-differentiated and undifferentiated SCCs were also studied for comparison. The BSCs showed many histopathologic similarities to cases previously reported. Among the CK subtypes analyzed, CK14 was the only subtype expressed by all basaloid cells of BSC. Potentially useful for the differential diagnosis was the finding of CKs 7 and 19 expression in the basaloid cells of ACC, and CKs 7 and 8 in basal cell adenocarcinoma. In BSCs, laminin and type IV collagen were found in the microcystic spaces between basaloid cells, but neither ACCs nor basal cell adenocarcinoma showed this feature. These data suggest that immunohistochemical findings are helpful in distinguishing BSC of the oral cavity from other histopathologically similar tumours.

Oral manifestations of paracoccidioidomycosis (South American blastomycosis)

Paracoccidioidomycosis (South American blastomycosis) is an uncommon, progressive systemic mycosis, potentially fatal if untreated. It is virtually restricted to persons spending time in Latin America. Reports of oral lesions are extremely rare in the English-language literature. Three adults with oral lesions as the first sign of paracoccidioidomycosis are described; this appears to be the largest series in the dental literature. The oral lesions had a characteristic appearance with a granular purpuric surface. The upper gingiva was a typical site, but lesions were also seen in the palate, tongue, and buccal mucosa. Two of the patients proved to have detectable pulmonary involvement. Long-term systemic ketoconazole therapy produced resolution of oral lesions in all cases.

Dental Alterations Associated with X-Linked Hypophosphatemic Rickets

The X-linked hypophosphatemic rickets is a rare metabolic disorder characterized by low serum phosphate levels caused by a decreased renal tubular reabsorption of inorganic phosphates. The initial complaints are a delay in the development of walking caused by deformity of the legs. Oral findings include poorly mineralized dentin, enlarged pulp chambers and root canals, and periradicular abscesses in caries-free teeth. We present three patients from the same family with X-linked hypophosphatemic rickets showing bone and dental alterations.

Clinicopathologic analysis of 493 cases of salivary gland tumors in a Southern Brazilian population

OBJECTIVE The aim of this study was to determine the distribution and demographic features of salivary gland tumors (SGTs) in a large Brazilian population. STUDY DESIGN A total of 493 cases of SGTs diagnosed between 2001 and 2011 from a general pathology laboratory and an oral pathology service were reviewed with respect to their clinicopathologic features. RESULTS A total of 369 tumors were benign and 124 were malignant. The mean age of patients with benign tumors was 46.3 years and that of patients with malignancies was 54.0 years. The parotid gland was the most common location (42.3%). Pleomorphic adenoma (PA) and Warthins tumor were the most common benign neoplasias, whereas mucoepidermoid carcinoma (MEC) and adenocarcinoma, not otherwise specified, were the most frequent malignancies. CONCLUSIONS The present data confirm that PA and MEC are the most common benign and malignant SGTs. However, it is important to consider that differences in tumor types may be influenced by whether a tumor derives from a medical or a dental service.

Comparative expression of syndecan-1 and Ki-67 in peripheral and desmoplastic ameloblastomas and ameloblastic carcinoma

The aims of the present study were to examine whether the pattern of syndecan‐1 expression correlates with cellular proliferation index in desmoplastic ameloblastomas (DA), peripheral ameloblastomas (PA) and ameloblastic carcinomas (AC), and to compare with that previously reported for solid (SA) and unicystic (UA) variants of ameloblastoma. Immunohistochemistry was performed for syndecan‐1 and Ki‐67 in seven ameloblastomas (four DA and three PA) and three AC. Expression of syndecan‐1 was related to the histological subtype of tumors and, in the case of malignancy, to lower expression levels observed in AC (22.5%) than in PA (47.5%) or DA (77.5%) (P < 0.05). Syndecan‐1 expression correlated inversely with Ki‐67 proliferative index: the expression was lower in both types of ameloblastomas (1.5% in DA and 6.4% in PA) than in AC (41.2%; P < 0.05). The present results suggest that the decrease in syndecan‐1 expression and increase in the Ki‐67 index observed in AC is in accordance with its higher aggressiveness as compared to the rare DA and PA. Interestingly, DA had a lower proliferation index as well as the highest levels of syndecan‐1 expression. These data suggest that DA differ from the other types of intraosseous ameloblastomas but more studies are necessary to better understand the role of this protein as a marker in the biological behavior of the epithelial odontogenic neoplasms.

Erratum: Paracoccidioidomycosis of the Mouth: an Emerging Deep Mycosis:

Oral fungal infections (mycoses) have come into particular prominence since the advent of infection with Human Immunodeficiency Virus (HIV), and recognition of the Acquired Immune Deficiency Syndrome (AIDS), as well as the phenomenal increase in world travel with increased exposure to infections endemic in the tropics. Paracoccidioidomycosis is a rare mycosis worldwide but common in Brazil and some other areas in Latin America. It can be life-threatening and can manifest with a spectrum of clinical presentations, including frequent oral lesions. This paper reviews the more recent information on Paracoccidioidomycosis, emphasizing those areas most relevant in dental science.