AIM: The aim of the present work was to analyze 20 cases of calcifying epithelial odontogenic tumour (CEOT), also known as "Pindborg tumour", and contrast the data with findings reported in the literature. MATERIALS AND METHODS: Twenty cases of CEOT filed in the archives of the Surgical Pathology Laboratory of the Oral Pathology Department, School of Dentistry, University of Buenos Aires, over a period of 63 years (1960-2023) were retrieved. Their histopathological, histochemical-immunohistochemical, and clinical-radiographic features were evaluated, and the obtained data were compared with those reported in the literature. RESULTS: CEOT accounted for 1% of odontogenic tumours and 0.02% of oral pathologies filed over the study period. Seventeen cases (85%) were intraosseous lesions (solid: 14 cases
cystic: three cases). Three cases (15%) were extraosseous (solid: two cases
cystic: one case). One case, an intraosseous tumour, was malignant. Three cases (15%) showed clear cells (intraosseous location: two cases
extraosseous location: one case), and two cases (10%) (intraosseous) had fusiform cells. All cases showed amyloid deposits and calcifications. Mean age was 36 years (10-71 years). A female predominance was observed (12 cases, 60%), and the prevalent location was the mandible (14 cases, 70%). CONCLUSIONS: CEOT is infrequent and presents a wide range of morphological features, making diagnosis challenging. Two cases in our series, intraosseous tumours, showed spindle cell epithelial proliferation, and one extraosseous case was cystic. To our knowledge, this is the first study to report these findings.