ABSTRACT
Imaging Craniopharyngioma is one tumor in which plain skull films may be useful. Suprasellar calcification is seen in over 75% of children and in somewhat less than half of adults. Enlargement of the sella with erosion of the anterior clinoids and dorsum sellae is also common. In the absence of calcification, plain skull films may show sellar enlargement, falsely suggesting a pituitary rather than a suprasellar tumor. CT scans are also sometimes useful, showing contrast enhancement of the solid portion of the tumor as well as identifying the typical calcifications, which are sometimes hard to see on MR scan. On MR, the cystic portion of the tumor may be either hyper-or hypointense on the T1-weighted image (cholesterol and keratin are hypointense on T1, whereas hemorrhage is hyperintense). On the T2-weighted image, cholesterol and hemorrhage are hyperintense and keratin hypointense. The solid portion of the tumor is usually hypointense on T1, hyperintense on T2, and contrast enhances. An MR angiogram may help the surgeon identify the relationship of the tumor to major vessels passing near the suprasellar cistern. An unusual sign of craniopharyngioma is the so-called ‘mustache’ sign.71 This sign is related to vasogenic edema caused by increased permeability of the blood-brain barrier in the optic tracts and optic radiations (Fig. 10.6). Vasogenic edema is thought to result from leakage of the craniopharyngioma contents, causing swelling and blood-brain barrier breakdown in the optic pathways. It is usually asymptomatic but may be misinterpreted as representing an optic nerve tumor rather than a craniopharyngioma.
