Clinical Symptoms and Magnetic Resonance Imaging Findings in Patients with Pituitary Stalk Interruption Syndrome

Pituitary stalk interruption syndrome (PSIS) is a rare syndrome characterized by absent or hypoplastic anterior pituitary gland, thin or absent infundibulum, and ectopic posterior pituitary location, occurring in 0.5/100,000 live births (Nawaz A et al. Radiol Case Rep 2018; 13: 503−506). It was firstly reported after surgical resection of pituitary stalk in idiopathic pituitary dwarfism patients (Fujisawa I et al. Radiology 1987; 165: 478−479). During the last decade the incidence appears to be rising, since the usage of magnetic resonance imaging is more widespread. The mean age of PSIS diagnosis varies, with the earliest reported median age 3.6 years (Gascoin-Lachambre G et al. PLoS One 2011; 6: e16367) and mean 4.0 years (Pinto G et al. J Clin Endocrinol Metab 1997; 82: 3450−3454). It may be associated with midline defects, and also with breech presentation, difficult delivery or neonatal distress (Pinto G et al. J Clin Endocrinol Metab 1997; 82: 3450–3454). The main cause of PSIS is yet unknown. There are numerous factors and conditions associated with PSIS, such as perinatal injuries, defective organogenesis due to genetic or environmental factors during pregnancy, and rare genetic mutations such as mutations of HESX1, LH4, OTX3 and SOX3 (Butenandt O al. Klin Padiatr 1996; 208: 26−32). PSIS is considered to be generally of hypothalamic origin. According to the current view, mode of delivery and/or neonatal hypoxemia are shown to be in direct or indirect relation to the hypothalamic-pituitary lesion. Patients with PSIS initially usually present with growth hormone deficiency, but clinical picture may progress to panhypopituitarism, while the posterior pituitary function usually appears to be maintained (van der Linden et al. Radiology 2007; 243: 594−597). Previously reported prevalence of isolated deficiency in growth hormone (GH), gonadotropin, corticotropin, thyrotropin were 100, 97.2, 88.2, and 70.3% respectively in a group of 74 adult patients (Wang W et al. Clin Endocrinol (Oxf) 2015; 83: 369−376). On MRI, the anterior pituitary gland is hypoplastic or sometimes even absent (Kornreich L et al. AJNR Am J Neuroradiol 1998; 19: 1495−1499). Ectopic localization of the posterior pituitary gland in patients with PSIS was described at the median eminence (Fujisawa et al. Radiology 1987; 165: 478−479), posterior to optic chiasm (Nawaz A et al. Radiol Case Rep 2018; 13: 503−506), at various points along the pituitary stalk (Chen S et al. J Clin Endocrinol Metab 1999; 84: 2408−2413). In the literature, the only 2 constant findings are ectopic posterior pituitary and growth hormone deficiency, while the pituitary stalk is usually absent although truncated or very thin. The visibility of the pituitary stalk shown on MRI might be an indication of the severity of PSIS (Wang W et al. Clin Endocrinol (Oxf) 2015; 83: 369−376). Therefore, some authors roughly divided those patients into 2 groups; IGHD (isolated growth hormone deficiency) and MPHD (multiple anterior pituitary hormone deficiency) (Kornreich L et al. AJNR Am J Neuroradiol 1998; 19: 1495−1499. Chen et al. J Clin Endocrinol Metab 1999; 84: 2408−2413). IGHD patients are usually older, presenting with short stature, truncated or thin pituitary stalk and can progress in MPHD. MPHD patients are younger, presenting with more severe clinical status and with no visible pituitary stalk. Other findings such as corpus callosum agenesis, vermis atrophy, epiphyseal cyst, arachnoid cyst, hydrocephalus, Arnold-Chiari type I malformation, optic atrophy, and spina bifida were also reported (Tauber M et al. Horm Res 2005; 64: 266−273). We present a series of 6 patients with clinical and radiological picture of PSIS.

Publication History

Article published online:
09 November 2020