Simple bone cyst of the mandibular condyle with severe osteoarthritis: report of a case.

A rare case of simple bone cyst in the mandibular condyle of a 33-year-old woman is reported. The condition was difficult to diagnose because the cyst was accompanied by severe osteoarthritis. T1-weighted magnetic resonance (MR) images revealed a cystic lesion with intermediate signal intensity within the condylar head and an irregular margin with intermediate signal intensity on the superior surface of the condyle. The patient was treated by high condylectomy, discectomy and reconstruction by sagittal split ramus osteotomy. Histopathological examination showed a simple bone cyst in the condylar head and erosion of the anterior articular surface due to degenerative changes.