What is the most likely diagnosis?
What is the main differential?
Hypothalamic-chiasmatic glioma, although enhancement is often present and involvement of the chiasm is common.
How do children with hypothalamic hamartomas present?
Gelastic seizures and central precocious puberty are the classical presenting features.
How are these lesions divided? Which one would this be?
Sessile or pedunculated. This mass is pedunculated, and it projects (hangs) down into the suprasellar cistern.
Selected images from an MRI of the brain demonstrate a rounded mass in the region of the hypothalamus, projecting inferiorly, behind the infundibulum of the pituitary gland. It is isointense to grey matter on T1 weighted images, does not enhance and is somewhat hyperintense of T2 weighted images.