A wolf in sheep’s clothing: malignant transformation of Ameloblastic Fibroma

With just over 100 cases reported to date, ameloblastic fibrosarcoma (AFS) is a rare and aggressive malignant odontogenic tumour that can arise de novo or develop from the malignant transformation of Ameloblastic Fibroma (AF). We report the case of a 28-year-old Malay lady who presented with a progressively enlarging, painless swelling over the left mandible, causing facial asymmetry and masticatory difficulties. Radiographic investigation revealed an expansile lesion with thin remaining cortical bone at the lower border of mandible. An incisional biopsy suggested AF, leading to surgical enucleation with peripheral ostectomy and Carnoy’s solution application. Postoperative histopathological examination, however, unexpectedly revealed areas of AFS within the lesion. Following a multidisciplinary consultation, close surveillance was recommended in view of clear surgical margins with no residual disease. The patient has completed 6 months of follow-up to date with no signs of recurrence. This case illustrates the difficulty of distinguishing AF from early-stage AFS and the need for long-term monitoring due to its malignancy potential. While radical surgery is typically the go-to treatment for AFS, this case suggests a more conservative approach with close monitoring may sometimes be appropriate. Nevertheless, further research is needed to develop clear guidelines for managing this rare malignancy.