Imaging description

A five-year-old girl presented to the emergency room with new onset of nausea, vomiting, and headaches. MRI showed a 36 × 26 × 30 mm multicystic suprasellar mass extending superior to the third ventricle (Fig. 3.1a, b) with areas of calcification and ventriculomegaly. An Ommaya device was placed in the right frontal lobe for cyst drainage. Pathology was consistent with craniopharyngioma. She was followed with serial MRI and CT scans. The imaging studies were stable for one and a half years when an MRI scan demonstrated further increase in the cystic and solid components of the suprasellar mass with increased ventriculomegaly. The patient underwent a right frontal endoscopic fenestration and partial resection of the suprasellar mass, with removal of the blocked Ommaya reservoir and placement of an external ventricular drainage system. Follow-up MRI showed increased size of the cystic mass and ventricles stable in size. However, there was evidence of mass compression of the optic chiasm. The patient underwent MRI-guided placement of a new right frontal Ommaya reservoir into the cystic portion of her tumor. Therapy with 32P (β emitter) colloid chromic phosphate was recommended by the treating physician. A diagnostic 99mTc sulphur colloid scan of the cystic tumor was performed to evaluate the distribution of the injected material on the inner surface of the tumor and to exclude the presence of a leak from the craniopharyngioma to the cerebrospinal fluid (CSF) space. The 99mTc sulphur colloid scan showed radiotracer migration from the Ommaya reservoir and coating of the suprasellar mass. However, uptake was also seen into the ventricular system, due to a leak (Fig. 3.1c, d). Due to this leak to the CSF space, the 32P chromic phosphate treatment was aborted in order to avoid excess radiation of normal central nervous system (CNS) structures.