A 7-year-old boy is being evaluated for growth retardation. Brain MRI shows a 4 cm multiloculated, cystic, suprasellar lesion, which is bulging into the floor of the third ventricle and base of the brain. Calcifications are present. From which of the following structures is this mass most likely derived?

Question

A 7-year-old boy is being evaluated for growth retardation.  Brain MRI shows a 4 cm multiloculated, cystic, suprasellar lesion, which is bulging into the floor of the third ventricle and base of the brain.  Calcifications are present.  From which of the following structures is this mass most likely derived?

Quizplus · Accepted Answer

Craniopharyngiomas are tumors arising from remnants of Rathke's pouch. The anterior pituitary is formed from an out-pouching of the pharyngeal roof and is called Rathke's pouch. The posterior pituitary gland arises from an extension of the hypothalamic neurons. Together, the anterior and posterior pituitary glands lie in the sella turcica at the skull base. During the time of pituitary development, remnants of Rathke's pouch cells can remain in the diencephalon (the posterior region of the forebrain). Neoplastic transformation of these "pouch cells" is called a craniopharyngioma. Typically, craniopharyngiomas have three components: solid, comprised of the actual tumor cells; cystic, filled with "machinery oil" liquid; and a calcified component. Any suprasellar mass with three components is highly suggestive of craniopharyngioma. Craniopharyngioma symptoms include headaches, visual field defects, and hypopituitarism, evidenced by the growth retardation of this child. Ultimately, compression of the pituitary stalk by craniopharyngioma leads to hyperprolactinemia by loss of dopaminergic inhibition. Craniopharyngiomas are usually tumors of childhood, being most frequently discovered between the ages of 5 and 10 years of age. (Choice A) Prolactinomas are uncommon in young children. They typically appear as a homogenous mass when imaged. (Choice C) Gliomas can occur in the suprasellar region if they arise from the optic apparatus, but do not appear on imaging with the three components described above. Gliomas typically presents with visual symptoms, hypothalamic dysfunction, and hypopituitarism. (Choice D) Meningiomas are tumors of the leptomeninges, which is the lining of the brain. Hence, meningiomas can occur in any "lined" part of the brain including sellar and suprasellar regions. Meningiomas are usually homogeneous appearance on MRI and can be seen "sticking" to leptomeninges. Educational Objective:

A 7-Year-Old Boy Is Being Evaluated for Growth Retardation