Endocrine Abstracts

Introduction: Pituitary stalk interruption syndrome is a congenital anomaly of the pituitary gland responsible for GH deficiency or global pituitary insufficiency, characterized by abnormalities visible on Magnetic Resonance Imaging (MRI) associating a thin or interrupted pituitary stalk, ectopic posterior pituitary, and hypoplastic anterior pituitary. Mutations in the HESX1 transcription factor or the LHX4 gene may be the cause of this anomaly, but a prenatal origin cannot be ruled out. This syndrome is often revealed during the neonatal period and childhood, but sometimes the symptoms can be overlooked and the diagnosis will therefore be delayed. We report a case of this syndrome diagnosed at a late stage.

Observation: 17-year-old patient admitted for failure to thrive and delayed puberty. Clinical examination reveals a harmonious dwarfism, a height of 156 cm (−2 standard deviation), a weight of 56 kg, the patient is classified G1P1 according to the Tanner classification, and the bone age was 13 years according to the Atlas of Greulich and Pyle. Hormonal assessment reveals a complete GH deficiency (following an insulin hypoglycaemia test), associated with hypogonadotropic hypogonadism. There was no corticotropic or thyrotropic deficit. Hypothalamohypophyseal MRI reveals a pituitary stalk interruption syndrome with ectopic posterior pituitary. Scrotal ultrasound concludes bilateral testicular hypotrophy. The patient is currently undergoing growth hormone replacement and regular monitoring.

Discussion: Pituitary stalk interruption syndrome is defined by morphological abnormalities on MRI: Pituitary stalk not visible, pituitary hypoplasia and ectopic post-pituitary. Stature prognosis remains pejorative if the diagnosis is late, hence the need for early detection of staturo-puberty delay.

Conclusion: Pituitary stalk interruption syndrome is a rare congenital malformation that must be considered in the presence of combined or isolated hypopituitarism. MRI is currently the most effective means of imaging for the diagnosis of this malformation.