Craniopharyngiomas are benign epithelial tumors that arise along the craniopharyngeal duct, commonly located in the sellar or suprasellar region. Infrasellar extension is a rare variant and may involve the nasopharynx, sphenoid sinus, clivus, and pterygopalatine fossa. A 66-year-old male patient is presented to the otorhinolaryngology service due to a complaint of left ear obstruction for the past 4 months. After no response to clinical treatment, investigation with computed tomography and magnetic resonance imaging showed a heterogeneous lesion with areas of calcification and bone destruction located in the sphenoid sinus region, which projected inferiorly and laterally invading the clivus in its entirety, the petrous apex, middle fossa, pterygopalatine, and infratemporal fossae with no involvement of the sellar/suprasellar region. The patient was referred to a multidisciplinary skull base surgery group that performed an extended transpterygoid endoscopic endonasal approach with gross total resection. The anatomopathological study was consistent with adamantinomatous craniopharyngioma. We present a rare case of a giant infrasellar craniopharyngioma with extensive invasion of the skull base without involvement of the sella or the pituitary gland.