Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Objective. To describe the clinicopathologic, immunohistochemical, and scanning electron microscopic features of 19 cases of calcifying epithelial odontogenic tumor (CEOT) in comparison to 4 cases of dental follicles containing CEOT-like areas (DF-CEOT). Study Design. A collaborative Latin American retrospective study. Results. CEOT and DF-CEOT showed a slight predilection for females, mostly affecting the posterior mandible. CEOTs were classified as epithelium-rich (8 cases), amyloid-rich (4), and calcification-rich (3), and 4 cases showed similar proportion of the 3 components. DF-CEOTs contained odontogenic epithelium, amyloid, calcification, and clear cells. Epithelial cells were positive for cytokeratins CK5 and CK19, E-cadherin, and syndecan 1 (CD138), and focally for amyloid A. In CEOT, amyloid was positive for CD138 and amyloid A, and calcification for CK5, CD138, and amyloid A. In DF-CEOT, calcification was positive for amyloid A. CEOT showed higher Ki-67 protein and minichromosome maintenance complex component 2 (MCM-2) labeling indices than did DF-CEOT. In scanning electron microscopy, CEOT calcified material resembled bone in the 3 cases classified as calcification-rich. Conclusions. CEOT and DF-CEOT showed histomorphologic and immunohistochemical similarities, and the histogenetic significance of these features should be further studied.1166759768Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)