<h4>Background</h4>The rarity of juvenile psammomatoid ossifying fibroma (JPOF) and lack of cytogenetic studies prompted us to report a novel SETD2 gene mutation in a benign odontogenic tumour.<h4>Case presentation</h4>A 21-year-old man presented with a hard, expanded mandibular cortex. The gene discussed is SETD2; the disease is odontogenic neoplasm.