Presentation
Confusion, falls and fatigue. Hypogonadotropic hypogonadism.
Patient Data
A large rounded mass of similar density to the adjacent brain is located in the anterior third ventricle, associated with hydrocephalus. No calcification. no extension into the pituitary fossa.
The rounded, somewhat heterogeneous, mass is located within the third ventricle, best seen on sagittal T1 imaging where the depression of the floor of the third ventricle and relationship to the optic chiasm can be clearly seen.
The mass is of somewhat lower T1 signal, high T2 signal and vividly enhancement with facilitated diffusion and no calcification, but speckled blood product at the periphery.
Conclusion:
The third ventricular mass has a differential diagnosis of papillary craniopharyngioma, chordoid glioma, choroid plexus papilloma (unusual location) and ependymoma (unusual location).
Case Discussion
The patient went on to have craniotomy with an interhemispheric transcallosal approach.
Histology:
Sections show anastomosing cords and sheets of squamous epithelium, which show peripheral palisading, surrounding loose fibrovascular cores containing foamy macrophages. No calcification or keratin are seen. No mitoses are identified.
On immunohistochemistry, the atypical cells are positive for BRAF V600E and show membranous Beta-catenin staining. Nuclear Beta-Catenin staining is not seen. CK7 shows patchy staining, predominantly in the superficial layer of squamous cells. Ki-67 is 2%.
FINAL DIAGNOSIS: papillary craniopharyngioma (WHO grade I)
Discussion:
Although craniopharyngiomas are thought of as suprasellar tumors, they can be entirely within the third ventricle. This is, admittedly rare. In such instances, they arise from the floor of the third ventricle and are usually of the papillary type in adults 1.