[A case of metastatic suprasellar tumor with edema along the optic pathway]

A rare case in presented of a patient with edema formation along the optic pathway, which was caused by metastatic suprasellar tumor mimicking craniopharyngioma. A 63-year-old female with visual disturbance, diabetes insipidus, and symptomatic panhypopituitarism was admitted to our hospital. CT images showed a suprasellar mass lesion. MR images demonstrated a heterogeneously enhanced tumor and edema along the optic nerve and tract. Although no cystic component is shown in radiological findings, these features are commonly observed in cases of craniopharyngioma. The patient underwent removal of the tumor by the transcranial approach. Since histological examination revealed adenocarcinoma, the tumor was diagnosed as metastatic brain tumor originating from non-recurrent rectal cancer operated on eight years previously. Conventional radiotherapy with a dose of 50GY was performed for the residual tumor. The tumor size was unchanged, but the edema had disappeared 7 months after the operation. Edema spreading along the optic tract was reported as a characteristic MR finding for diagnosis of craniopharyngiomas as distinguished from other common parasellar tumors. However, it is suggested that edema of the optic pathway seems to be caused not only by craniopharyngioma but also other suprasellar lesions. Even if there was a characteristic radiological finding for some specific diseases, metastasis should be kept in mind as a differential diagnosis, because of its various appearance in neuroimages.