Pituitary stalk interruption syndrome, also known as pituitary stalk transection syndrome, is a syndrome characterised by an absent or hypoplastic anterior pituitary gland, thin or absent infundibulum, and ectopic posterior pituitary location.

Terminology

The term pituitary stalk interruption syndrome should not be used interchangeably with ectopic posterior pituitary, which is only one of the features of pituitary stalk interruption syndrome.

Epidemiology

Pituitary stalk interruption syndrome is rare, with an estimated incidence of 0.5 in 100,000 births ⁵. 

Clinical presentation

Patients with pituitary stalk interruption usually present early in life, either in the first decade of life with a deficiency of growth hormones resulting in short stature or during puberty due to a lack of developing secondary sexual characteristics ^1,6. This may progress to multiple pituitary hormone deficiencies with the eventual development of panhypopituitarism with preservation of posterior pituitary function ^2,4.

The combination of hyperprolactinaemia and hypothyroidism is known as Pickardt syndrome ⁴.  

In addition to endocrinological manifestations, there appears to be an increased incidence of breech presentation and difficult delivery ⁴. A number of additional features may be encountered later in childhood, including learning difficulties and seizures ^4,7. 

Pathology

Various hypotheses have been proposed to explain the syndrome such as defective migration of the pituitary gland during intrauterine life or ischaemia with subsequent reorganisation of the infundibular axons and development of an ectopic posterior pituitary ¹.

Radiographic features

MRI

MRI is required for the diagnosis and demonstrates ⁴: 

• absent/hypoplastic anterior pituitary gland

• thin or absent infundibulum

• ectopic posterior pituitary

Additional features include optic nerve hypoplasia ⁷.

Treatment and prognosis

Treatment consists of hormonal replacement ³.