Benign osteoblastoma of the mandible.

Benign osteoblastoma is a rare osteoblastic tumour with osteoid and bone deposition. A rapidly growing osteoblastoma involving the area of the mandibular first and second molar of a 20-year-old female is described. Investigation of the collagenous components of the tumour by immunofluorescence was suggestive of a normal collagen synthesis by the tumour osteoblasts. The lesion is discussed with particular emphasis on its differential diagnosis and matrix constituents.