Primordial odontogenic tumour: clinicopathological analysis of six cases of a previously undescribed entity.

AIM: To describe the clinicopathological and immuno-histochemical features of six tumours that do not fulfil the criteria of any of the currently classified odontogenic tumours. METHODS AND RESULTS: The patients were three males and three females, whose ages ranged from 3 years to 18 years (mean, 11.05 years). In all cases there were well-defined radiolucencies associated with unerupted teeth apparently showing a pericoronal relationship. Microscopically, all tumours were composed of variably cellular loose fibrous tissue with areas similar to dental papilla, entirely surrounded by cuboidal to columnar epithelium resembling the internal epithelium of the enamel organ. Mesenchymal tissue was positive only for vimentin, and Ki67 expression was very low (<2%). The epithelium was positive for CK AE1/AE3, CK5, CK14, and CK19, but negative for CK18 and CK20. All cases showed clear demarcation from the surrounding bone, and were surgically removed, with no recurrences after follow-up ranging from 6 months to 20 years. CONCLUSIONS: These findings differ from those observed in other odontogenic lesions, such as ameloblastic fibroma, odontogenic myxoma, odontogenic fibroma, and hyperplastic dental follicles. The term primordial odontogenic tumour is proposed to describe this novel lesion.

Peripheral developing odontoma in newborn. Report of two cases and literature review.

Extra-osseous odontogenic tumors are rarely observed. However, it is widely accepted that the remains of odontogenic epithelium entrapped in the oral soft tissues may be a possible source for peripheral odontogenic tumors differentiation. Peripheral developing odontoma is considered exceptionally rare, since few similar cases are described in the English-related literature under diverse nomenclature, such as irregular eruption, ectopic tooth, ectopic soft-tissue mesiodens, ectopic odontoma and extra-osseous tooth germ. Previously reported cases invariably affected children and surgical exploration revealed tooth germs exclusively embedded in the soft tissue without bone involvement. Microscopically, all these cases exhibited developing tooth germs composed of ameloblasts, enamel matrix, odontoblastic layer, dentin and dental papilla and the morphological findings seem to depend on the developmental stage of each tooth germ at discovery. Thus, we believe that it is relevant to report two additional cases that were recently diagnosed in Brazil and Guatemala, focusing on their nomenclature, correct diagnosis and further treatment.

Odontogenic myxoma: clinico-pathological, immunohistochemical and ultrastructural findings of a multicentric series.

The aim of this study was to analyze the clinico-pathological and immunohistochemical features of 62 cases of odontogenic myxoma (OM) diagnosed in three Oral Pathology Diagnostic Services in Latin America, as well as to describe the ultrastructural features of three of these cases. OM showed a wide age range (9-71 years), with a mean of 27.97 yr (SD: 11.01) and a male to female ratio of 1:2.2. Mandible was affected in 37 cases (59.6%) and maxilla in 25 (40.4%), with 61.3% located in the posterior region. Thirty-nine cases (62.9%) were multilocular and 23 (37.1%) unilocular. Size ranged from 1 to 13 cm, (mean: 5.2 cm). Thirty-seven multilocular (54.8%) and 6 unilocular lesions (26%) were larger than 4 cm (p<0.05). Epithelial islands were identified in 5 cases (8%) on H&E stained sections, but AE1/AE3 and CK14 disclosed these structures in 15 cases each (24.2%); CK5 was positive in 8 (12.9%); CK7 in 2 (3.2%) and CK19 in only 3 cases (4.8%). All cases were negative for CKs 8 and 18, S-100 protein, NSE and CD68, and showed a low index of expression of Bcl2 and ki-67 proteins (<1%). Mast cell antibodies showed these cells in 45 cases (72.6%). Myofibroblastic differentiation evidenced by myofilaments and fibronexi was found in one case out of the three studied by TEM and 29 cases (46.7%) were positive by immunohistochemistry for alpha actin. In conclusion, only a minority of OM had epithelial islands, and only 3 cases expressed CK 19, indicating an odontogenic epithelium origin. Immunohistochemical and ultrastructural findings suggest that OM is a mesenchymal neoplasm in which several factors may contribute to its pathogenesis, including myofibroblastic differentiation and the participation of mast cell products. However, further investigations are needed to better understand the participation of these elements in this particular neoplasm.

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.

Acinic cell carcinoma of the oral and maxillofacial region: an international multicenter study

Abstract The aim of this study was to describe the prevalence, clinicopathological, and prognostic features of acinic cell carcinoma (AciCC) of the oral and maxillofacial region. AciCC cases were retrospectively retrieved from 11 pathology centers of three different countries. Medical records were examined to extract demographic, clinical, pathologic, and follow-up information. A total of 75 cases were included. Females (65.33%) with a mean age of 45.51 years were mostly affected. The lesions usually presented as an asymptomatic (64.28%) nodule (95.66%) in the parotid gland (70.68%). The association of two histopathological patterns was the most common finding (48.93%) and the tumors presented mainly conventional histopathological grades (86.11%). Surgical treatment was performed in the majority of the cases (59.19%). Local recurrence was observed in 20% of the informed cases, regional metastasis in 30.43%, and distant metastasis in 12.50%. The statistical analysis showed that the cases with a solid histopathological pattern (p=0.01), high-grade transformation (p=0.008), recurrence (p=0.007), and regional metastasis (p=0.03) were associated with poor survival. In conclusion, high histopathological transformation, presence of nodal metastasis, and recurrence were prognostic factors for AciCC of the oral and maxillofacial region.

Oral melanoacanthoma and oral melanotic macule: a report of 8 cases, review of the literature, and immunohistochemical analysis.

Oral melanoacanthoma (MA) is a rare, benign pigmented lesion, similar to cutaneous MA, characterized by hyperplasia of spinous keratinocytes and dendritic melanocytes. The pathogenesis of oral MA remains uncertain, although its clinical behavior is suggestive of a reactive origin. The most common intraoral sites are the buccal mucosa, lip, palate and gingiva. The average age of presentation is 28 years, mainly in blacks, with a strong female predilection. The oral melanotic macule (MM) is a small, well-circumscribed brown-to-black macule that occurs on the lips and mucous membranes. The etiology is not clear and it may represent a physiologic or reactive process. The average age of presentation is 43 years, with a female predilection. A biopsy is recommended to distinguish these lesions from each other and from other oral melanocytic lesions. We depict four cases each of oral MA and MM, affecting Caucasian and Latin American mestizo patients. The clinicopathological features of these cases reflect its ample spectrum, and to the best of our knowledge, it is the first example of oral MA affecting a Caucasian boy reported in the English literature. Therefore oral MA and MM should be considered in the differential diagnosis of pigmented lesions in the oral mucosa in these populations.

Clinicopathological and immunohistochemical study of 39 cases of Adenomatoid Odontogenic Tumour: a multicentric study.

Adenomatoid Odontogenic Tumour (AOT) is a relatively uncommon odontogenic lesion and few studies describing its cytokeratin profile have been reported in the English-language literature. Thirty-nine cases of AOT from three Oral Diagnosis services (Brazil, Mexico and Guatemala) were studied, considering their clinical, radiographic, and histological features and immunohistochemical expression of cytokeratins (AE1/AE3, 34betaE12, CK1, CK5, CK6, CK7, CK8, CK10, CK13, CK14, CK16, CK18, and CK19), vimentin and Ki-67. Sixty five percent of cases affected women, anterior maxilla was the preferred site and radiographically most cases showed unilocular radiolucency with well defined sclerotic borders. Calcifying epithelial odontogenic tumour (CEOT)-like areas were found in 36 out of 39 cases, and 10 cases showed positivity for Congo red in polarized light. All cases were positive for AE1/AE3, 34betaE12, CK5, CK14 and CK19. CEOT-like areas were negative for CK 19. Vimentin was also expressed in 27 cases and this profile may indicate the existence of a variable phenotype in certain areas of the tumour. There were no recurrences after surgical treatment, and this can be related to the low proliferative activity observed in all cases with Ki-67 marker.

Odontoameloblastoma. Clinico-pathologic study of three cases and critical review of the literature.

The odontoameloblastoma (OA), is an infrequent neoplasm. To date, there are less than 50 cases reported as OA or ameloblastic odontoma in the English dental literature, but only 14 (including three of our own material), fulfill the histological criteria of the current WHO histological classification of odontogenic tumours. Nine occurred in men and five in women (male to female ratio 1.8:1). Age ranged from 2 to 50 years (mean 20.2 years), and nine cases (64.2%) were diagnosed during the first two decades. Maxilla and mandible were equally involved, and most cases occurred posterior to the canines (71.4%). Follow-up ranged from 6 months to 8 years (mean: 25.5 months). Of the 12 cases with informed follow-up, two recurred once (at 24 and 18 months, respectively), and one case had two documented recurrences, at 6 and 49 months. Although OA tends to occur at an earlier age than conventional ameloblastoma, it has practically the same potential to produce bone expansion, root resorption and recurrence. For these reasons OA should be treated in a similar fashion, with wide surgical excision and close follow-up for at least 5 years.

Kohlschütter-Tönz Syndrome - Report of an additional case.

Kohlschütter-Tönz Syndrome is a rare disorder clinically characterized by amelogenesis imperfecta, epilepsy and progressive mental deterioration. We present an additional case of this syndrome of a nine year-old boy who was referred by pigmented teeth. The mental deterioration was associated with speech delay, impulsive behavior, attention-deficit/hyperactivity disorder, and learning problems. The physical examination revealed a reduction of lower third, slightly palpebral fissures, low ear and hair implantation, coarse hair and hypertrichosis. The intraoral examination showed alteration in teeth pigmentation diagnosed as amelogenesis imperfecta. Although rare, the present case report illustrates a syndrome that has dental anomalies and systemic alterations. It is important to recognize this syndrome as early as possible and paediatric dentist may contribute to the diagnosis and consequently to better manage the patients. Key words:Kohlschütter-Tönz syndrome, amelogenesis imperfecta, seizures, mental deterioration.

Central odontogenic fibroma: new findings and report of a multicentric collaborative study.

OBJECTIVE: The aim of this study was to describe the clinicopathologic and immunohistochemical characteristics of 14 cases of central odontogenic fibroma (COF), and the ultrastructural features of 2 of them. STUDY DESIGN: Collaborative retrospective study based on the records of 4 oral pathology diagnostic services in Latin America based on the current World Health Organization classification. RESULTS: There were 7 male and 7 female patients (mean age 31.8 years). Eight tumors occurred in the maxilla and 6 in the mandible. Thirteen cases were epithelium-rich and 1 epithelium-poor COF. Three were classified as hybrid COF with giant cell lesion. Mean size of the hybrid lesions were larger than pure COF (3.8 vs. 2.4 cm). Odontogenic epithelial islands were immunoreactive for cytokeratin (CK) AE1/AE3, CK5, CK14, CK19, and 34BE12 and negative for CK1 and CK18. Langerhans cells positive for S-100 and CD1a were found within the epithelial islands in 6/6 tested cases. CD68 was expressed in the giant cells of the hybrid lesions and in a few mononuclear cells of 2 cases of COF. Ki-67 index was <1% in all cases. In 6 tumors (42.8%), there were small globular eosinophilic droplets within the epithelial islands, which were positive for collagen type IV, and 9/13 cases (69.2%) were focally positive for smooth muscle actin. In addition to fibroblasts, myofibroblastic differentiation was found in the 2 cases studied ultrastructurally. CONCLUSIONS: Immunohistochemistry was useful to confirm the presence of epithelium and to exclude other central fibrous tumors. COF also contains a variable number of mast cells, Langerhans cells, and myofibroblasts, and further studies are needed to better understand the participation of these cells in COF histogenesis.

Primary intraosseous adenoid cystic carcinoma of the mandible: histopathological and immunohistochemical analysis.

Primary intraosseous salivary gland tumors of the mandible are rare, with mucopidermoid carcinoma being the most frequent, followed by adenoid cystic carcinoma (ACC). We present a case of a central ACC involving the mandible of a 46-year-old man. He presented an indurated swelling on the vestibular aspect of the left mandibular body and ipsilateral paraesthesia of the lower lip. A panoramic radiography revealed a large radiolucent area, with irregular margins, involving the body and ramus of the left mandible, and CT scan confirmed that the lesion was confined within the mandibular bone. The histopathological features were of an ACC. CT scan also revealed multiple nodular lesions in both lungs suggestive of metastases. The patient was surgically treated by hemi-mandibulectomy. The patient is well with no evidences of recurrences in the mandible. The present case shows that the clinical and immunohistochemical profile of primary intraosseous ACC is similar to what is found in ACC involving the salivary glands.

Epithelioid osteosarcoma of the mandible: a rare case with unusual immunoprofile.

A 42-year-old woman presented a large, nontender, quickly progressive mass in the left mandible. Radiograph showed extensive destruction of the angle, posterior body, and ramus of the left side of the mandible. The patient was surgically treated by hemimandibulectomy. Microscopically, the tumor was composed of large epithelioid cells, many of them showing polarized nuclei, and evident eosinophilic cytoplasm. The predominant pattern was trabecular, and rosette-like structures were also observed. Typical osteoid-containing cells surrounded by malignant cells were found in a few areas. Immunohistochemistry for a large panel of antibodies showed positivity for osteocalcin, osteonectin, osteopontin, VS38c, and S-100. CD34 saliented the hemangiopericytoma-like distribution of the blood vessels. Collagen I was focally positive for the extracellular matrix and malignant osteoid. All other markers were negative, including vimentin and cytokeratins. To the best of our knowledge, this is the first case of epithelioid osteosarcoma affecting the mandible and the second case affecting the jaws that has been reported in the literature.

An updated clinical and epidemiological profile of the adenomatoid odontogenic tumour: a collaborative retrospective study.

BACKGROUND: Adenomatoid odontogenic tumour (AOT) is a benign odontogenic jaw lesion. The aim of this study was to update the biological profile of AOT. MATERIAL AND METHODS: Cases published in the literature and cases in files of co-authors were included. RESULTS: 550 new cases were retrieved, and of a total of 1082 cases analysed, 87.2% were found in the second and third decades. The M:F ratio was 1:1.9. 70.8% were of the follicular variant (extrafollicular: 26.9%, peripheral: 2.3%). 64.3% occurred in the maxilla. 60% of follicular AOTs were associated with unerupted canines. Nineteen cases of AOT (2.8%, M:F ratio was 1:1.4) were associated with embedded third molars. Twenty-two peripheral AOTs (2.3%, M:F ratio was 1:5.3) were recorded. The relative frequency (RF) of AOT ranged between 0.6% and 38.5%, revealing a considerably wider AOT/RF range than hitherto reported (2.2-7.1%). CONCLUSIONS: This updated review based on the largest number of AOT cases ever presented, confirms the distinctive, although not pathognomonic clinicopathological profile of the AOT, its worldwide occurrence, and its consistently benign behaviour.