Malignant transformation of craniopharyngioma: case report and review of the literature.

Craniopharyngioma is considered to be a benign intracranial tumor. Malignant transformation of craniopharyngioma has rarely been described. In this article, we report a case of ameloblastic carcinoma arising from a previously benign craniopharyngioma in a 42-year-old woman. The patient was diagnosed with craniopharyngioma in August 2004 and underwent surgical resection of a typical craniopharyngioma, the pathological result was craniopharyngioma, papillary and adamantinomatous types. During the subsequent 5 years, this patient experienced two recurrences, for which surgical resections were performed without radiotherapy. The last two pathologic diagnoses were malignant craniopharyngiomas and there was more apparent sign of malignancy in the third pathologic section. The exact pathogenesis and the biological behavior of malignant change in craniopharyngioma are not yet clear. We review the relevant literature of malignant craniopharyngioma. Histopathologic, clinical and imaging features of malignant craniopharyngioma and the possible effect of radiotherapy on the carcinogenesis are discussed.