Figure 1
MRI of the pituitary gland
Ectopic neurohypophysis in a child with anterior hypopituitarism
SectionNeuroradiology
Case TypeClinical Cases
AuthorsParth S Patel, I D Desai
Connected authors
8 years, male
Clinical History
Eight-year-old child presented with short stature and recurrent seizures. Clinical examination showed growth retardation, micro penis and undescended testes. Laboratory examination revealed low insulin-like growth factor 1, poor cortisol response to hypoglycaemia and delayed thyrotropin secreting response. MRI brain and sella was performed.
Imaging Findings
MRI revealed hyperintense signal at median eminence on T1 weighted images suggestive of ectopic posterior pituitary. Pituitary stalk was not visualized and anterior pituitary gland was hypoplastic.
Discussion
Neurophysin-vasopressin complex or lipid-rich wall of secretory vesicle has been responsible for T1 hyperintense signal of neurohypophysis. [1]
Ectopic signal suggests disruption of the normal axonal pathway leading into neurohypophysis. When the stalk is transacted, a high signal may be identified ectopically above normal level neurohypophysis. [2]
Breech deliveries, perinatal asphyxia and postnatal trauma have been associated with hypopituitarism secondary to transaction of pituitary stalk. [3]
HESX1 gene plays a role in development of pituitary gland. Heterozygous mutations in this gene has been associated with pituitary anomalies including ectopic neurohypophysis. [4]
Pituitary stalk interruption syndrome is characterized by the absence of normal pituitary stalk and an ectopic neurohypophysis. Non-visualization of stalk is associated with lack of anterior pituitary function. Ectopic neurohypophysis functions normally as there is no posterior pituitary hormone deficiency. [5]
MRI can show characteristic pituitary anatomic abnormality in patients with hypopituitarism. An ectopic hyperintense T1 signal is associated with absent or thin pituitary stalk and absent or small anterior pituitary gland. Fat suppression images help to differentiate ectopic neurohypophysis from hypothalamic lipoma. [6]
MRI is the modality of choice in evaluation of pituitary–hypothalamic morphology and associated anomalies.
Ectopic signal suggests disruption of the normal axonal pathway leading into neurohypophysis. When the stalk is transacted, a high signal may be identified ectopically above normal level neurohypophysis. [2]
Breech deliveries, perinatal asphyxia and postnatal trauma have been associated with hypopituitarism secondary to transaction of pituitary stalk. [3]
HESX1 gene plays a role in development of pituitary gland. Heterozygous mutations in this gene has been associated with pituitary anomalies including ectopic neurohypophysis. [4]
Pituitary stalk interruption syndrome is characterized by the absence of normal pituitary stalk and an ectopic neurohypophysis. Non-visualization of stalk is associated with lack of anterior pituitary function. Ectopic neurohypophysis functions normally as there is no posterior pituitary hormone deficiency. [5]
MRI can show characteristic pituitary anatomic abnormality in patients with hypopituitarism. An ectopic hyperintense T1 signal is associated with absent or thin pituitary stalk and absent or small anterior pituitary gland. Fat suppression images help to differentiate ectopic neurohypophysis from hypothalamic lipoma. [6]
MRI is the modality of choice in evaluation of pituitary–hypothalamic morphology and associated anomalies.
Differential Diagnosis List
Pituitary stalk transaction syndrome
Hypothalamic lipoma
-
Final Diagnosis
Pituitary stalk transaction syndrome
References
[1] Kucharczyk J, Kucharczyk W, Berry I, de Groot J, Kelly W, Norman D, Newton TH (1989) Histochemical characterisation and functional significance of hyperintense signal on MR images of the posterior pituitary. AJR Am J Roentgenol Jan; 152:1, 153-157 (PMID: 2783270)
[2] Fujisawa I (2004) Magnetic resonance imaging of the hypothalamic-neurohypophyseal system. J Neuroendocrinol Apr;16(4):297-302 (PMID: 15089965)
[3] Ultmann MC, Siegel SF, Hirsch WL, Finegold DN, Foley TP Jr (1993) Pituitary stalk and ectopic hyperintense T1 signal on magnetic resonance imaging. Implications for anterior pituitary dysfunction. Am J Dis Child Jun;147(6):647-52 (PMID: 8506833)
[4] Corneli G, Vivenza D, Prodam F, Di Dio G, Vottero A, Rapa A, Bellone S, Bernasconi S, Bona G (2008) Heterozygous mutation of HESX1 causing hypopituitarism and multiple anatomical malformations without features of septo-optic dysplasia. J Endocrinol Invest Aug;31(8):689-93 (PMID: 18852528)
[5] Sorkin JA, Davis PC, Meacham LR, Parks JS, Drack AV, Lambert SR (1996) Optic nerve hypoplasia: absence of posterior pituitary bright signal on magnetic resonance imaging correlates with diabetes insipidus. Am J Ophthalmol Nov;122(5):717-23 (PMID: 8909213)
[6] Chaudhary V, Bano S (2012) Imaging of pediatric pituitary endocrinopathies. Indian J Endocrinol Metab Sep;16(5):682-91 (PMID: 23087850)
Case information
| URL: | https://www.eurorad.org/case/14075 |
| DOI: | 10.1594/EURORAD/CASE.14075 |
| ISSN: | 1563-4086 |
License
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Figure 2
MRI brain
MRI brain axial and sagittal images showing pineal cyst.
MRI of the pituitary gland
MRI of the pituitary gland T1 weighted sagittal image showing ectopic neurohypophysis, hypoplastic anterior pituitary gland and absent pituitary stalk.
Parth Patel, Department of Radio diagnosis, Civil Hospital, Ahmedabad, Gujarat, India.
Parth Patel, Department of Radio diagnosis, Civil Hospital, Ahmedabad, Gujarat, India.
T1 fat saturation image showing hyperintense signal of ectopic neurohypophysis differentiating from lipoma.
Parth Patel, Department of Radio diagnosis, Civil Hospital, Ahmedabad, Gujarat, India.
Parth Patel, Department of Radio diagnosis, Civil Hospital, Ahmedabad, Gujarat, India.
MRI brain
MRI brain axial and sagittal images showing pineal cyst.
Parth Patel, Department of radio diagnosis, Civil Hospital, Ahmedabad, Gujarat, India.
Parth Patel, Department of radio diagnosis, Civil Hospital, Ahmedabad, Gujarat, India.