The tuber cinereum is a part of the hypothalamus located between the mamillary bodies and the optic chiasma. A hamartoma is a focal malformation that resembles a neoplasm; it is not a malignant tumor and it is composed of tissue elements normally found at that site that grow in a disorganized mass.

Hypothalamic hamartoma in the brain typically occurs in the hypothalamus and presents as a discrete mass isointense to cortex on both T1 and T2, without contrast enhancement (notice that this picture is a post-contrast T1). This lesion may cause gelastic seizures, visual problems or early onset of puberty. The symptoms often begin in early infancy and are progressive, often with general cognitive and/or functional disability.

Curiously: tuber cinereum is named after its color in fact, being gray matter it is called “cinereum” - the color of the ash.

The word “hamartoma” derives from the greek “hamartia”: in Greek tragedy, the concept of “hamartia” is an error in judgment or unwitting mistake, normally applied to the actions of the hero…in the same view, in medicine, hamartoma is considered an error of development.

“Gelastic” is a term often used in medical terminology to indicate an association of a symptom or syndrome with laughter. The word originates from the Greek “gelaein” that means “to laugh”.

Case courtesy of Dr Eytan Raz.