Pigmented ameloblastic fibro-odontoma: clinical, histological, and immunohistochemical profile.

Ameloblastic fibro-odontoma (AFO) is a slow-growing, expansive, benign odontogenic tumor, composed of ameloblastic epithelium embedded in an ectomesenchymal stroma resembling dental papilla, containing hard dental tissue in variable degrees of maturation, including enamel, dentin, and sometimes cementum. AFO typically affects the posterior mandible, causing bony expansion. We report a case of pigmented AFO in a 5-year-old boy, comprising clinical and histological features illustrated by immunohistochemistry using a large panel of antibodies, polarized light microscopy and scanning electron microscopy.

Ectomesenchymal chondromyxoid tumor: histopathologic and immunohistochemical study of two cases without a chondroid component.

Ectomesenchymal chondromyxoid tumor (ECT) is a rare benign neoplasm usually affecting the anterior dorsum of the tongue. Histopathologically, it is formed by spindle, round and/or polygonal cells embedded in a chondromyxoid matrix. Immunohistochemical positivity for vimentin, S-100 protein, glial fibrillary acid protein and neuron-specific enolase are helpful to confirm the diagnosis. There are 42 cases of ECT of the tongue reported in the English language literature, three of them showing no chondroid matrix. We describe two additional cases of ECT lacking the chondroid component, exhibiting areas of reticulated myxoid and cellular pattern. Considering the microscopical features, ECT can be classified in classic and 'chondroid-free' variants, the latter including the reticulated myxoid and cellular patterns. It is important to consider that the cellular ECT usually exhibits predominance of an infiltrative atypical cellular component that may mimic a malignant tumor.

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.

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.

Tumores odontogénicos en Puebla / Odontogenic tumors in Puebla

Los tumores de origen odontogénico representan un conjunto de entidades patológicas exclusivas de los huesos de la región maxilomandibular. La importancia de su diagnóstico clínico, radiográfico y microscópico radica en las serias implicaciones de su tratamiento y pronóstico. Se presenta un estudio retrospectivo sobre estas entidades a partir del análisis de 2.859 biopsias vistas en la Unidad de Diagnóstico de la ciudad de Puebla, México. En el presente estudio, estas entidades representaron el 0.24 por ciento, siendo el ameloblastoma de tipo quístico la lesión más frecuentemente hallada y representó el 57.1 por ciento de los tumores odontogénicos estudiados. Se discuten los aspectos antomoclínicos, de tratamiento y pronóstico y se hace énfasis en la importancia del diagnóstico preciso para estas lesiones, ya que como se reporta en la literatura, este grupo de entidades tienden a producir una gran destrucción del hueso y presentan complicaciones importantes