Abstract
Giant cell tumor (GCT) of the skull is an extremely rare condition, accounting for less than one percent of all bone GCTs. Clival GCT is even rarer, with only 25 cases documented to date. It generally follows a benign course; however, due to its location and vascularity, it can be locally aggressive. Complete resection of GCT in this location may be challenging, resulting in residual tumors. In this paper, we report a case of a 19-year-old male who presented with a chronic headache later accompanied by diplopia and was noted to have a mass spanning the sella and the clivus on cranial imaging. The histopathology report of the excised mass revealed findings compatible with GCT of the bone. Most GCTs remain stable in the first two years after initial treatment. However, four months after its partial excision, the clival GCT continued to progress. The patient underwent adjuvant radiation therapy, yet symptoms persisted. This profile highlights the crucial role of long-term surveillance and prompt adjuvant radiation therapy and chemotherapy.