<prompt> A 42-year-old man complains of headache when he wakes up in the morning. It lasts into the afternoon and then subsides. Headache has been present for a few months. CT scan shows a frontal lobe mass with focal areas of calcification. You strongly suspect the patient hasAn astrocytomaA pinealomaA meningiomaAn oligodendroglioma  <response>: A frontal headache when waking up in the morning and a computerized tomography CT scan showing a frontal lobe mass with focal areas of calcification are characteristic findings in oligodendrogliomas, which commonly involve the frontal lobe. These are tumors derived from oligodendrocytes that frequently locate in the cerebral hemispheres of adults 30 to 50 years of age. Calcifications are visible on routine skull films or CT in 90 of cases. They commonly have an admixture with other types of glial tumors, such as an astrocytoma 50. Overall, oligodendrogliomas have a good prognosis but a high recurrence rate. 