Paediatric ImagingHypopituitarism
decreased or absent function of the
pituitary gland. In children hypopituitarism may be caused by the presence of tumours, such as
craniopharyngioma, optic chiasm or hypothalamic glioma, or germinoma. Unlike adults hypopituitarism secondary to
pituitary microadenoma or macroadenoma is rare in childhood. Hypopituitarism may also be seen after surgery particularly for lesions in the suprasellar cistern.
Congenital abnormalities, such as
pituitary hypoplasia or aplasia may also occur.
Pituitary aplasia is usually fatal at birth. Hypoplasia results in varying degrees of hypopituitarism including adenohypophyseal and neurohypophyseal deficiencies. Many of these patients are found to have a small
pituitary gland and fossa and the posterior
pituitary may be in an ectopic position, usually in the region of the
pituitary infundibulum or hypothalamus.
These anomalies may only be detected by high resolution coronal and sagittal MR imaging of the pituitary region. An ectopic pituitary is seen as a bright spot in the region of the tuber cinereum on sagittal T1-weighted sequences with concomitant absence of the normal posterior pituitary bright spot in the pituitary fossa. The pituitary fossa may be small and appear empty, an 'empty sella'. The condition may be associated with septo optic dysplasia and midline facial anomalies such as mid-facial cleft, and midline cerebral anomalies such as agenesis corpus callosum.
EP