Giant Cell Tumor

Abstract

Giant cell tumor took the #12 position for ACF abnormalities as a “common” lytic, locally aggressive expansile tumor characterized by regular recurrence and sporadic metastasis. Although generally benign, 5–10% are malignant. Our Classic Clue describes a young adult female presenting with headache and cranial nerve deficits who is found to have an aggressive appearing, destructive, lytic skull base lesion exhibiting avid enhancement with fluid-fluid levels. Pertinent CT and MRI features are described including T1, T2, and T1 Gd. Multiple representative MRI images are provided for perusal. Treatment and prognosis are discussed. Incidence: Only in medicine would we call “common” a bone tumor which involves one person in a million. While 2% of giant cell tumors involve the head and neck, only 1% involve the skull. GCTs typically tend to be histologically benign but locally aggressive. However, 5–10% undergo malignant transformation. They may metastasize when both the primary and secondary lesions are “histologically benign”. Somewhat suggestive of the “Strange Case of Dr. Jekyll and Mr. Hyde,” GCTs present pathologists with “histologically benign” patterns while simultaneously parading malevolent manifestations before radiologists. GCTs regularly appear radiographically indistinguishable from malignant tumors. And, they may metastasize while the pathologist is still signing them off as being benign!