Hamartoma of the Tuber Cinereum
Findings:
Multiple MR images demonstrate a nonenhancing mass within the posterior aspect of the suprasellar cistern which is contiguous with the floor of the third ventricle. The mass demonstrates slight T2 and FLAIR hyperintensity. It arises from the region of the tuber cinereum.
Differential Diagnosis:
Chiasmatic astrocytoma is the main differential diagnosis, but enhancement would be expected in this location. The other considerations of craniopharyngioma and germinoma are less applicable due to the expected cystic and/or enhancing nature of craniopharyngioma and enhancement of germinoma.
Discussion:
These lesions may present clinically as precocious puberty or gelastic seizures (laughing and/or crying spells). The location and signal characteristics are fairly characteristic, isointense to grey matter on T1 and isointense to hyperintense on T2 with no enhancement. The presence of cysts or fat are very rare and should suggest an alternate diagnosis. Pathologically, it is considered a migrational anomaly and may secrete or stimulate LHRH accounting for central precocious puberty. Larger size seems to correlate with risk for seizures and the seizures may progress to more typical tonic-clonic or partial complex types. Treatment is directed at seizure control and hormonal suppression with surgery considered for tumor growth or inability to medically control symptoms.