The Common Vein Copyright 2010
A hypothalamic hamartoma is a congenital malformation characterized by the overgrowth of tissues including neurons and glial cells. It is thought to arise from a neuronal migrational error during embryologic development which generally presents in the first two decades of life.
Clinically patients can present with either precocious puberty secondary to the secretion of luteinizing hormone releasing hormone or gelastic seizure (fits of laughter).
Histologically, hypothalamic hamartomas contain both nerve cells and glial cells.
Hypothalamic hamartomas are best seen by MRI. They are located just anterior to the mamillary bodies. They match gray matter on T1 images and are slightly hyperintense to gray matter on T2 and otherwise match normal characteristics of gray matter without enhancement, fat, cystic change, or calcification.
There is no treatment necessary for the primary lesion in an asymptomatic patient. Hormonal therapy can be used to halt precocious puberty allowing the patient to grow.