Ameloblastic fibrosarcoma or odontogenic carcinosarcoma: a matter of classification?

A biphasic odontogenic tumor with aggressive clinical behaviour is reported. The tumor arose posterior to the right mandibular third molar involving the angle of the mandible and the ascending ramus. Within a 5 years period the patient suffered from two episodes of local progression and final disease generalization occurred 6 years after initial surgical therapy. On histopathologic evaluation, both recurrences and the distant metastasis preserved the biphasic pattern seen in the primary tumor with both epithelial and mesenchymal components exhibiting clear cytological features of malignancy. There was no evidence of sarcomatous overgrowth within the progression of the tumor. By contrast, the proportion of the epithelial component was even enlarged in the second recurrence. Thus, both pathologic features and clinical behaviour clearly distinguishes this tumor from ameloblastic fibrosarcoma and demonstrates the clear morphological as well as clinical characteristics of a true malignant mixed type tumor with a definite sarcomatous and carcinomatous component. Thus, even though a very rare lesion, our case supports the consideration of the odontogenic carcinosarcoma as an individual entity.