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.

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.

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