Growth Hormone Deficiency with Ectopic Neurohypophysis: Anatomical Variations and Relationship between the Visibility of the Pituitary Stalk Asserted by Magnetic Resonance Imaging and Anterior Pituitary Function

Abstract

In GH-deficient children showing ectopic posterior pituitary hyperintense signal (EPP), the anatomical details of the pituitary-hypothalamic region and the relationship between the visibility of the pituitary stalk and anterior pituitary function were studied by magnetic resonance imaging (MRI). The absence or presence of the pituitary stalk was recorded by MRI before and after the injection of gadolinium in 25 children with GH deficiency and EPP at the age of 8.7+/-5.0 yr (16 males and 9 females). Patients were classified into 2 groups according to the presence (group 1; n = 14), or the absence (group 2; n = 11) of pituitary stalk visibility after gadolinium injection. Most patients in group 1 (12 of 14) demonstrated isolated GH deficiency, whereas all but 1 patient in group 2 showed multiple anterior pituitary hormone deficiency. The prevalence of a normally sized adenohypophysis was higher in group 1 than in group 2 (50% vs. 9%; P<0.05). Although the EPP was found at the median eminence in all group 2 patients, it was visualized in group 1 at different levels of the pituitary stalk in 60% of cases (8 of 14; at the proximal end of the pituitary stalk, n = 4; in the middle of the pituitary stalk, n = 2; at the distal end of the pituitary stalk, n = 2). This demonstrates that the ectopic posterior pituitary migration abnormality may be complete or partial. In conclusion, although the pathogenesis of GH deficiency with EPP remains unclear, these results suggest that in cases of GH deficiency associated with ectopic posterior pituitary hyperintense signal, patients with no visible pituitary stalk on MRI after gadolinium injection present a more severe form of the disease in childhood associated with multiple anterior pituitary hormone deficiency, whereas visibility of the pituitary stalk is related to isolated GH deficiency. Nevertheless, careful follow-up of these latter patients is necessary, as the natural history of the disease is not established until adulthood.

Gonadotrophic status in adolescents with pituitary stalk interruption syndrome

“…As described in previous series of patients with PSIS 3,9,12 only a few patients (2/27) had high PRL levels. This observation is surprising as pituitary stalk lesions are most commonly associated with 'disconnection' hyperprolactinaemia (i.e.…”

“…1,2 Anomalies of the hypothalamopituitary region revealed by MRI have been correlated in many patients with the degree of anterior pituitary dysfunction. [3][4][5][6][7][8][9][10][11][12] These anomalies include decreased height of the anterior pituitary gland, an absent or thin pituitary stalk and ectopic location of the posterior pituitary (EPP), and have been termed the pituitary stalk interruption syndrome (PSIS). Its association with GH deficiency is well appreciated.…”

“…14 Anatomo-clinical correlations were described by some authors: among patients with EPP, an inability to visualize the stalk after Gadolinium injection was predictive of multiple PHDs and not of isolated GH deficiency. 4,9,15 The first proposed pathophysiological mechanism leading to PSIS was birth trauma, owing to the high frequency of obstetric complications and perinatal anoxia observed in these children. 16 However, additional evidence argues for a developmental defect (disordered embryogenesis leading to anatomical anomalies).…”

Interruption Syndrome Pituitary Stalk: About 8O Cases

“…Only the severe nature of hypoplasia less than 2 mm is predictive of multiple pituitary deficits as found Bozzola (1996), Chen (1999), and Cacciari (1990). These findings were verified in this study.…”

“…In the literature this percentage varies between 4 and 52%. Therefore, it cannot explain the SITP in all cases (Chen, 1999;Kandemir et al, 2000). The breech is 5 to 10 times more frequent in the GH deficiency (BH et al, 1997).…”