Pediatric Ectopic Posterior Pituitary

  • Etiology: Disruption of normal embryogenesis of the posterior pituitary
  • Imaging MRI:
    — Adenohypophysis and sella are small
    — Posterior pituitary bright spot not in neurohypophysis but instead is along median eminence of hypothalamus or along pituitary infundibulum or stalk which may be tiny or absent
    — Associated midline CNS abnormalities: septo-optic dysplasia, lobar holoprosencephaly, olfactory bulb anomalies
  • DDX:
  • Complications: Associated adenohypophysis dysfunction may be related to absent infundibulum
  • Treatment:
  • Clinical: Frequently associated with growth hormone deficiency (pituitary dwarfism) leading to short stature and diabetes insipidus

Radiology Cases of Ectopic Posterior Pituitary

MRI of ectopic posterior pituitary gland
Sagittal T1 MRI without (above) and with contrast (below) of the sella shows the high signal intensity posterior pituitary bright spot, which should be located posteriorly in the sella turcica, is instead located in the superior aspect of the pituitary stalk / inferior aspect of the hypothalamus. The pituitary gland is otherwise unremarkable.
MRI of pituitary interrupted stalk syndrome
Sagittal (above) and coronal (below) T1 MRI without contrast of the sella shows absence of the pituitary stalk between the sella and the hypothlamus. In addition, the high signal intensity posterior pituitary bright spot, which should be located posteriorly in the sella turcica, is instead located in the inferior aspect of the hypothalamus.