MR imaging of pineocytoma: report of two cases.

The patient was a 36-year-old woman who manifested no remarkable abnormalities except headache, which suggested elevated intracranial pressure. Serum human chorionic gonadotropin and alphafetoprotein values were normal. CT and MR examinations were performed (Figs. 1 A-1 D). CT revealed a solid tumor with punctate calcification on the pineal region. MR distinctly marked the presence of the tumor on the pineal region extending to the posterior part of the third ventricle. By angiography, only a mass effect was seen without visualization of tumor vessels or tumor stain . As radiation therapy (30 Gy) had no effect in reducing the size of the tumor, surgery was performed. The tumor was solid . Light microscopy showed medullary cell proliferation with rosette formation and incomplete lobulation, which is identical histologically to pineocytoma. Electron microscopic examination (Fig . 1 E) confirmed that this tumor was a pineocytoma with neuronal differentiation [2).