Malignant behavior of a craniopharyngioma: A case report and open questions

Malignant craniopharyngioma is a rare sellar and suprasellar tumor characterized by high cellularity, marked atypias, and high mitotic index. It may develop de novo or by malignant transformation of a previously treated benign craniopharyngioma (usually after radiotherapy). The prognosis is extremely poor in all cases. We report a case of a 58-year-old man who presented with a 4-month history of visual disturbances, amnesia, and confusion. Brain magnetic resonance imaging (MRI) showed a large intrasellar and suprasellar lesion with solid and cystic components. The tumor was partially removed through a right pterional craniotomy; postoperative MRI revealed residual tumor in the interpeduncolar fossa. Histopathologic examination showed adamantinomatous craniopharyngioma. At 1 month after discharge, the patient experienced amnesia and disorientation. A new MRI showed an extraordinary increase of the residual suprasellar component. A second surgery through a transcallosal approach was performed but was complicated by significant bleeding from the tumor itself. The second histologic evaluation revealed neither significant cellular atypia nor necrosis but an elevated proliferative index. The patient never regained consciousness. A new brain MRI performed 5 weeks after the second surgery showed a regrowth of the tumor. The patient died from acute respiratory insufficiency 7 weeks after the second surgery. We report a case of a highly aggressive craniopharyngioma in which the clinical criteria, but not the histologic characteristics, were compatible with the diagnosis of malignant craniopharyngioma. The issue of the pathologic diagnosis and of the definition of malignancy will be reviewed and discussed.