(21.01) Pituitary Stalk Interruption Syndrome, presenting as Micropenis and Short Stature

Pituitary stalk interruption syndrome (PSIS) is a rare entity with an estimated incidence rate of 0.5/1,000,000 births. PSIS is characterized by the presence of a thin or absent pituitary stalk, associated hypoplastic or aplastic anterior pituitary and ectopic posterior pituitary on MRI. The endocrine outcome is usually the progressive onset of hormone deficiencies leading to panhypopituitarism, but posterior pituitary function is usually maintained. The clinical presentation in terms of severity and timing of presentation depends on the hormones affected and associated deformities; they can present immediately after birth, early childhood, adolescent or in adult with varying severity of endocrine deficiencies.

We present a case of PSIS in an eight-year-old male child who is brought to medical attention because of micropenis but is also found to have clinical characteristics of multiple anterior pituitary hormone deficiency, as manifested by short stature, Central hypothyroidism, Micropenis, cryptorchidism.

Case(s) Description :

An eight-year-old male child brought to medical attention by his parents with small genitalia and underdeveloped scrotum since birth. He was born full term without complication. Early neonatal period within first 12 hours of life was significant in terms of episodes of severe hypoglycemia, hypothermia with seizures, hyponatremia and hyperkalemia. Underdeveloped genitalia with bilateral cryptorchidism was also noted. Karyotyping showed 46, XY, Hormonal profiles in early neonatal periods were normal. He was treated with hydrocortisone and fludrocortisone and was tapered and stopped subsequently within 2-3 weeks. He has been well with no chronic medical problems or hospitalizations since then. He weighed 15 kg and was 107 cm in height (< 3^rd percentile). Penile length was 3 cm consistent with micropenis.
Basic metabolic panel was normal. He had low fT4, serum cortisol and IGF-1 level suggesting Central hypothyroidism, adrenal insufficiency and GH deficiency. A plain X-ray hand left hand was consistent with bone age of 5.8 years. Pituitary MRI confirmed the diagnosis of PSIS.

Discussion :

Pituitary stalk interruption syndrome is primarily encountered in infancy and childhood but is often overlooked due to subtle clinical signs. PSIS is a heterogeneous, multigenic disorder with high phenotypic variability. The spectrum of clinical presentation depends on the severity of the defect, pituitary hormonal deficiencies present, and associated malformations. Early identification of the conditions, confirmation of the hormonal deficiency, and timely and appropriate substitution of the missing hormones as soon as possible will have a better prognosis and quality of life. Patients’ follow-up through life is essential for early identification of hormonal deficiency since there is progressive development of endocrine deficiency.