novo, they found that more than half the re ported cases arose from a previously existing benign amelo blastic fibroma. Among cases that underwent malignant transformation, a history of multiple surgical procedures was a prominent feature. The average patient age was 26 years, and the male-to-female ratio was 1.6:1. The mandible was involved in 73% of the cases and the maxilla in 27%. A melo blastic fibrosarcoma tends to recur, especially when by curettage or local excision. Metastases also have been reported. RADIOLOGY (Figs. 11-23 to 11-20 The findings of Trodahl (1972) shed some light on the value of routine radiologic examinations in the dental office be- cause 17% of their cases were detected as incidental radio logic with many lesions, the radio characteristics of this tumor have been described poorly. The following is a summary 1. In patients younger than 20 years, cases are found in the posterior mandible 2. An impacted is present, but not alway This large and e t because an unerupted a tooth is invo radiologically