= single lesion of altered vascular + reactive response within bone

Age:<30 years (75%); in girls + young women

• painless swelling, tenderness on palpation

Location: mandible÷maxilla = 2÷1

Site: anterior to 1^st molar (= deciduous teeth); propensity for crossing midline (especially in maxilla)

• small unilocular area of lucency (early)
• multilocular honeycomb with wispy internal septa (later)
• expansion of bone + erosion / remodeling of cortex
• displacement of teeth + root resorption
• usually well-defined border

DDx: brown tumor of HPT (histologically similar)