Giant Cell Tumor of the Central Skull Base.

Giant cell tumor (GCT) of bone is an uncommon indolent tumor, typically occurring in the meta-epiphysis of long bones in young adults. GCT arising in the clivus is exceedingly rare, and even more uncommon in the pediatric population. We present a case of a 13-year-old patient diagnosed with a large GCT in the clivus. Initial clinical and radiographic findings were suspicious for a GCT, although other more common skull base tumors were also considered in the differential diagnosis. Certain key radiographic features suggested the diagnosis of a GCT, including the low T2 signal within the mass on MRI and the T2 hypointense rim corresponding with a cortical shell present on CT. An endoscopic biopsy confirmed the diagnosis. This report highlights the unique diagnostic challenges and broad differential in this case while underscoring the role of imaging in detection and precise anatomic delineation that helps guide therapeutic decisions and improve patient prognosis.