Imaging of the Pediatric Hypothalamic-Pituitary Axis:
How Embryology Sheds Light on Pathology
ASNR 2015 Annual Meeting
Jayant Boolchand, MD
Bruno P Soares, MD
Abstract No: eEdE-171
Submission Number:275
Department of Radiology and Imaging Sciences
Division of Neuroradiology
Disclosures
The authors have no relevant disclosures.
Pituitary embryology
 Adenohypophysis
 Derives from Rathke’s pouch, an ectodermal outpouching of stomodeum
and infundibulum, at approximately 24 days gestation

Rathke’s pouch consists of: anterior wall, a precursor of the anterior lobe and pars
tuberalis; posterior wall, which develops into the pars intermedia; and a central cleft
 Course and development of Rathke’s pouch:

Originates rostral to the oropharyngeal membrane

Migrates dorsally via a canal in the body of the sphenoid bone

Separates from the oral cavity in the 7th week of life

Craniopharyngeal canal regresses and normally becomes obliterated by six months
 Primitive pituitary cells undergo differentiation and produce hormones
(TSH, GH, prolactin, LH, FSH)
Schroeder JW, Vezina LG. Pediatric sellar and suprasellar lesions. Pediatr Radiol. 2011 Mar;41(3):287-98; quiz 404-5. doi: 10.1007/s00247-010-1968-0. Epub 2011 Jan 26. Review. PubMed PMID: 21267556.
Spampinato MV, Castillo M. Congenital pathology of the pituitary gland and parasellar region. Top Magn Reson Imaging. 2005 Jul;16(4):269-76. Review. PubMed PMID: 16785842.
Shields R, Mangla R, Almast J, Meyers S. Magnetic resonance imaging of sellar and juxtasellar abnormalities in the paediatric population: an imaging review. Insights Imaging. 2015 Apr;6(2):241-60. doi: 10.1007/s13244015-0401-5. Epub 2015 Mar 21. PubMed PMID: 25794595.
Pituitary embryology
 Adenohypophysis
 Consists of:

Pars tuberalis – surrounds the infundibulum

Pars intermedia – portion of midline cells in Rathke’s pouch; separates adenohypophysis from
neurohypophysis

Pars distalis – enlarges and becomes the anterior lobe; extends superiorly along the anterior
aspect of infundibulum
 Neurohypophysis
 As Rathke’s pouch is developing, the posterior lobe originates from
neuroectodermal evagination of tissue from the hypothalamus/floor of the third
ventricle/diencephalon
 Functionally composed of: posterior lobe, the infundibulum and the medial
eminence of the hypothalamus
 Secretes oxytocin and vasopressin synthetized in the hypothalamus
Schroeder JW, Vezina LG. Pediatric sellar and suprasellar lesions. Pediatr Radiol. 2011 Mar;41(3):287-98; quiz 404-5. doi: 10.1007/s00247-010-1968-0. Epub 2011 Jan 26. Review. PubMed PMID: 21267556.
Castillo M. Pituitary gland: development, normal appearances, and magnetic resonance imaging protocols. Top Magn Reson Imaging. 2005 Jul;16(4):259-68. Review. PubMed PMID: 16785841
Hamilton BE, Salzman KL, Osborn AG. Anatomic and pathologic spectrum of pituitary infundibulum lesions. AJR Am J Roentgenol. 2007 Mar;188(3):W223-32. PubMed PMID: 17312027.
Pituitary embryology
 Pituitary Stalk
 Variably hollow tube that arises from the ventromedial
hypothalamus and is contiguous with the infundibular recess of
the third ventricle
 Though the most distal aspect of the infundibulum differentiates
into the neurohypophysis, the pituitary stalk has components of
both the anterior and posterior lobes, which explains the
presence of adenomas arising in the stalk
 Pars tuberalis encircles the infundibulum as it enters the
adenohypophysis
Castillo M. Pituitary gland: development, normal appearances, and magnetic resonance imaging protocols. Top Magn Reson Imaging. 2005 Jul;16(4):259-68. Review.
PubMed PMID: 16785841
Hamilton BE, Salzman KL, Osborn AG. Anatomic and pathologic spectrum of pituitary infundibulum lesions. AJR Am J Roentgenol. 2007 Mar;188(3):W223-32.
PubMed PMID: 17312027.
Normal development of the
pituitary gland
Shields R, Mangla R, Almast J, Meyers S. Magnetic resonance imaging of sellar and juxtasellar abnormalities in the paediatric population: an imaging review.
Insights Imaging. 2015 Apr;6(2):241-60. doi: 10.1007/s13244-015-0401-5. Epub 2015 Mar 21. PubMed PMID: 25794595.
Normal pituitary anatomy
Shields R, Mangla R, Almast J, Meyers S. Magnetic resonance imaging of sellar and juxtasellar abnormalities in the paediatric population: an imaging review.
Insights Imaging. 2015 Apr;6(2):241-60. doi: 10.1007/s13244-015-0401-5. Epub 2015 Mar 21. PubMed PMID: 25794595.
Normal pituitary anatomy
Delman BN. Imaging of pediatric pituitary abnormalities. Endocrinol Metab Clin North Am. 2009 Dec;38(4):673-98. doi: 10.1016/j.ecl.2009.09.001. Review.
PubMed PMID: 19944287.
Normal pituitary anatomy
Delman BN. Imaging of pediatric pituitary abnormalities. Endocrinol Metab Clin North Am. 2009 Dec;38(4):673-98. doi: 10.1016/j.ecl.2009.09.001. Review.
PubMed PMID: 19944287.
Imaging appearance of neonatal
gland

Adenohypophysis

In newborns T1 hyperintense, gradually becomes T1 isointense to the pons by 6-8 weeks

Signal intensity reflects the newborn’s postnatal age and not the gestational age at birth

At birth, the gland is physiologically enlarged with a concave superior margin; then flattens,
and takes a more globular shape

Height of gland decreases in the first 8 weeks

In preterm infants the gland is taller than in normal-term infants, thought to be due to
reduced IGF-1 and higher levels of growth hormone in premature infants

Neurohypophysis


T1 hyperintense
Infundibulum

Usually midline, but may insert off center in up to 46% of patients

Should be no larger than 2.6 mm

May be seen by MRI after fetus is 25 weeks
Schroeder JW, Vezina LG. Pediatric sellar and suprasellar lesions. Pediatr Radiol. 2011 Mar;41(3):287-98; quiz 404-5. doi: 10.1007/s00247-010-1968-0. Epub 2011 Jan 26. Review. PubMed PMID: 21267556.
Castillo M. Pituitary gland: development, normal appearances, and magnetic resonance imaging protocols. Top Magn Reson Imaging. 2005 Jul;16(4):259-68. Review. PubMed PMID: 16785841
Shields R, Mangla R, Almast J, Meyers S. Magnetic resonance imaging of sellar and juxtasellar abnormalities in the paediatric population: an imaging review. Insights Imaging. 2015 Apr;6(2):241-60. doi: 10.1007/s13244-015-04015. Epub 2015 Mar 21. PubMed PMID: 25794595.
Normal T1 hyperintense
appearance of the neonatal gland
Normal globular appearance of
the neonatal gland
Imaging appearance of
childhood and adolescent gland
 Experiences linear and constant growth, reaching a
height of approximately 6 mm
 At puberty, the gland enlarges, and tends to be slightly
larger in height in girls (10 mm) than in boys (8 mm)
 In girls, it is not uncommon for the gland to convex
superiorly; the size of the gland may also vary with the
menses, becoming slightly larger just before
menstruation; generally does not measure more than
10 to 12 mm in height
Castillo M. Pituitary gland: development, normal appearances, and magnetic resonance imaging protocols. Top Magn Reson Imaging. 2005 Jul;16(4):259-68.
Review. PubMed PMID: 16785841
Normal physiologic prepubertal
pituitary hyperplasia
Gland during pregnancy
 Increase in gland size from 30-100%, particularly in the third
trimester; upwardly convex border
 Occasionally, the adenohypophysis becomes somewhat T1
bright
 Reaches it maximum size a few days after birth and gradually
returns to normal (regardless of breast-feeding choices)
 May cause bitemporal hemianopsia
 Histologically, the number of lactotrophs increases until it
compromises nearly 60% of total cell population of the gland
Castillo M. Pituitary gland: development, normal appearances, and magnetic resonance imaging protocols. Top Magn Reson Imaging. 2005 Jul;16(4):259-68.
Review. PubMed PMID: 16785841.
Normal postpartum gland
Imaging appearance of pituitary
infundibulum

Tapers from superior to inferior

3.45 +/- 0.56 mm at the level of the optic chiasm and narrows to 1.91 +/- 0.4 mm at its
insertion

Signal intensity on T1 usually less than optic chiasm

Lacks blood brain barrier and thus normally enhances

Deviation is common and does not necessarily imply underlying disease, especially
in cases where the floor of the sella may slope normally to one side

Insertion of intersphenoid septum at the floor of the sella may result in artifacts that
may be confusing. Magnetic susceptibility-induced signal loss in the gland at the
level of the septal insertion must not be confused with an adenoma
Hamilton BE, Salzman KL, Osborn AG. Anatomic and pathologic spectrum of pituitary infundibulum lesions. AJR Am J Roentgenol. 2007 Mar;188(3):W223-32.
PubMed PMID: 17312027.
Castillo M. Pituitary gland: development, normal appearances, and magnetic resonance imaging protocols. Top Magn Reson Imaging. 2005 Jul;16(4):259-68.
Review. PubMed PMID: 16785841.
Imaging appearance of the
neurohypophysis

Etiology of increased T1 signal (“bright spot”) is controversial–
believed to be related to vasopressin neurosecretory granules
(neurophysin); lipoid bodies in pituicytes; presence of phospholipid
vesicles

If the stalk is anatomically and functionally normal, an intrasellar bright
spot is present. Functional damage to the stalk results in absence of
the bright spot

Dehydration results in a smaller bright spot, due to active secretion of
ADH

Overhydration results in a larger bright spot, due to accumulation of
the hormone in the posterior lobe
Castillo M. Pituitary gland: development, normal appearances, and magnetic resonance imaging protocols. Top Magn Reson Imaging. 2005 Jul;16(4):259-68.
Review. PubMed PMID: 16785841.
Persistent craniopharyngeal
canal

Skull base midline defect at the level of the sphenoid, connecting the
floor of the sella with the superior wall of the nasopharynx; usually
measures less than 1.5 cm

Lack of involution of the craniopharyngeal canal can contain pituitary
tissue

Pathway of Rathke’s pouch is the craniopharyngeal canal, which
progressively normally involutes by 6-7 weeks of gestation

In cases where the canal persists, can be associated trans-sphenoidal
meningoencephaloceles, ectopic pituitary tissue, sphenoid teratoma and
infrasellar craniopharyngiomas

Insult during 42-45 days of gestational life can lead to persistence of
canal
Spampinato MV, Castillo M. Congenital pathology of the pituitary gland and parasellar region. Top Magn Reson Imaging. 2005 Jul;16(4):269-76. Review. PubMed PMID:
16785842.
Shields R, Mangla R, Almast J, Meyers S. Magnetic resonance imaging of sellar and juxtasellar abnormalities in the paediatric population: an imaging review. Insights
Imaging. 2015 Apr;6(2):241-60. doi: 10.1007/s13244-015-0401-5. Epub 2015 Mar 21. PubMed PMID: 25794595.
Ectopic pituitary tissue within a persistent
craniopharyngeal canal
Ectopic pituitary tissue within a persistent
craniopharyngeal canal
Transsphenoidal encephalocele

Wide spectrum of congenital abnormalities affects the skull base in the region of the sella
turcica, ranging from persistent craniopharyngeal canal to transsphenoidal and
sphenoethmoidal cephalocele

Congenital malformation involving the lack of separation of neuroectoderm from surface
ectoderm results in failure of localized bone formation or from failed fusion of ossification
centers

Herniation of CSF filled sac containing neural and vascular tissue

Content may include the hypothalamus, pituitary gland, third ventricle, anterior cerebral
arteries, optic nerves and chiasm

May present with feeding and nasal obstruction in the first year, and potential for CSF leaks
and meningitis

Associated with agenesis of the corpus callosum, hypertelorism, craniofacial midline defects,
dysfunction of the hypothalamopituitary axis, and optic pathway abnormalities
Spampinato MV, Castillo M. Congenital pathology of the pituitary gland and parasellar region. Top Magn Reson Imaging. 2005 Jul;16(4):269-76. Review. PubMed PMID:
16785842.
Shields R, Mangla R, Almast J, Meyers S. Magnetic resonance imaging of sellar and juxtasellar abnormalities in the paediatric population: an imaging review. Insights
Imaging. 2015 Apr;6(2):241-60. doi: 10.1007/s13244-015-0401-5. Epub 2015 Mar 21. PubMed PMID: 25794595.
Ectopic neurohypophysis

When ectopic usually located along the ventral aspect of the hypothalamus
(median eminence)

Absent, truncated, or thread-like pituitary stalk; small adenohypophysis

Almost always accompanied by decreased hypothalamic – pituitary function

Most common imaging finding in children with growth retardation

Can be isolated finding or associated with other midline anomalies, such as lobar
holoprosencephaly, septic-optic dysplasia, pituitary dwarfism, delayed skeletal
maturation, Kallman syndrome, dysgenesis of the corpus callosum

May also develop following trauma

If stalk transected at the proximal aspect, axons from the hypothalamus may reorganize to
store and release vasopressin
Schroeder JW, Vezina LG. Pediatric sellar and suprasellar lesions. Pediatr Radiol. 2011 Mar;41(3):287-98; quiz 404-5. doi: 10.1007/s00247-010-1968-0. Epub 2011 Jan
26. Review. PubMed PMID: 21267556.
Shields R, Mangla R, Almast J, Meyers S. Magnetic resonance imaging of sellar and juxtasellar abnormalities in the paediatric population: an imaging review.
Insights Imaging. 2015 Apr;6(2):241-60. doi: 10.1007/s13244-015-0401-5. Epub 2015 Mar 21. PubMed PMID: 25794595.
Ectopic neurohypophysis
Rathke cleft cyst

Nonneoplastic cysts arising from failure of obliteration of the embryonic cleft of Rathke pouch;
arise from epithelial rests of the craniopharyngeal canal; usually between the anterior and
posterior lobes in the region of the pars intermedia

Walls of cyst lined with columnar or cuboidal epithelium; contains fluid and variable amounts of
protein, mucopolysaccharides and/or cholesterol

May be intrasellar only, but most are intra- and suprasellar (87%)

2-3 times more common in women

May be symptomatically related to compression of adjacent structures

Most are stable in size, some may disappear spontaneously; may slowly increase in size
because of imbalance between secretion and reabsorption of cyst contents

Cyst growth and/or intracystic hemorrhage or infection can occasionally cause visual
disturbances, headaches, diabetes inspidus, or pituitary dysfunction
Schroeder JW, Vezina LG. Pediatric sellar and suprasellar lesions. Pediatr Radiol. 2011 Mar;41(3):287-98; quiz 404-5. doi: 10.1007/s00247-010-1968-0. Epub 2011 Jan 26.
Review. PubMed PMID: 21267556.
Spampinato MV, Castillo M. Congenital pathology of the pituitary gland and parasellar region. Top Magn Reson Imaging. 2005 Jul;16(4):269-76. Review. PubMed PMID:
16785842.
Shields R, Mangla R, Almast J, Meyers S. Magnetic resonance imaging of sellar and juxtasellar abnormalities in the paediatric population: an imaging review. Insights
Imaging. 2015 Apr;6(2):241-60. doi: 10.1007/s13244-015-0401-5. Epub 2015 Mar 21. PubMed PMID: 25794595.
Rathke cleft cyst

Intermediate or high signal intensity on T1 and T2; signal characteristics vary
based on protein content

Thin peripheral enhancement of the wall; no central or solid enhancement

Intracystic nodules – no enhancement; low signal intensity on T2


Mucinous mixed cholesterol and protein
ADC increased compared to cystic components of craniopharyngiomas and
hemorrhagic pituitary adenomas

May have mass effect on the infundibulum, pituitary gland or infundibulum

Pars intermedia cysts – less than 3 mm, asymptomatic, incidental and difficult to
distinguish from Rathke cleft cyst
Schroeder JW, Vezina LG. Pediatric sellar and suprasellar lesions. Pediatr Radiol. 2011 Mar;41(3):287-98; quiz 404-5. doi: 10.1007/s00247-010-1968-0. Epub
2011 Jan 26. Review. PubMed PMID: 21267556.
Sellar/Suprasellar Rathke cleft
cyst
Pars intermedia cyst
Craniopharyngioma
 50% of pediatric suprasellar tumors; 3% of all intracranial tumors
 Histologically benign, locally aggressive; occur in bimodal
distribution in children (<10 years) and adults (>40 years)
 Two types: adamantinomatous type (all age groups) and papillary
type (almost always adults)
 Suprasellar component in 95% of cases
 Extension in middle cranial fossae in up to 30% of cases
 Frequently contain proteinaceous fluid (bright on T1), cysts, lipid
components and calcifications
Schroeder JW, Vezina LG. Pediatric sellar and suprasellar lesions. Pediatr Radiol. 2011 Mar;41(3):287-98; quiz 404-5. doi: 10.1007/s00247-010-1968-0. Epub
2011 Jan 26. Review. PubMed PMID: 21267556.
Craniopharyngioma
 Intermediate and/or high signal on T1 and T2 with or without
nodular or rim enhancement
 Adamantinomatous (bimodal in children and adults)
 Hyperintense cystic components (T1), lobulated shape and vascular
encasement
 Squamous – papillary subtype (adults)
 Hypointense cysts (T1), enhancing solid components- results in flip flop of T1
signal between cystic and solid portions comparing pre and post imaging
 Mets may occur via tumor transplantation during surgery or
CSF dissemination
Schroeder JW, Vezina LG. Pediatric sellar and suprasellar lesions. Pediatr Radiol. 2011 Mar;41(3):287-98; quiz 404-5. doi: 10.1007/s00247-010-1968-0. Epub
2011 Jan 26. Review. PubMed PMID: 21267556.
Craniopharyngioma

Two hypotheses for development:

Embryogenetic theory: adamantinomatous subtype comes from remnants of Rathke pouch
or craniopharyngeal duct – the duct and pouch are derived from the stomadeum, which form
(among other things) teeth primordia

Metaplastic theory: squamous papillary subtype occurs from neoplasia of squamous cell
rests – remnants of the part of the stomadeum that contribute to the buccal mucosa


Classified by size and relationship to the optic chiasm

Sellar CP

Prechiasmatic suprasellar CP

Retrochiasmatic CP

Giant CP (anterior, middle, or posterior cranial fossae)
Neurosurgeon needs to be aware of relationship to hypothalamus, third
ventricle and arteries of the Circle of Willis
Schroeder JW, Vezina LG. Pediatric sellar and suprasellar lesions. Pediatr Radiol. 2011 Mar;41(3):287-98; quiz 404-5. doi: 10.1007/s00247-010-1968-0. Epub
2011 Jan 26. Review. PubMed PMID: 21267556.
Craniopharyngioma
 50% suprasellar tumors
 Adamantinous
 90% have Ca++
 90% cystic
 90% enhance
 May expand sella! (arises
along path of Rathke’s pouch)
Pituitary hyperplasia
 May enlarge from stimulation by the hypothalamus and
mimic true mass
 Homogeneous appearance on all pulse sequences
 May be physiological – can reach 10 mm or even
higher, especially in females
 Thyrotrophs will enlarge in the setting of chronic hypothyroidism
 Somatotrophs will enlarge in the setting of pheochromocytomas
 Lactotrophs will enlarge during pregnancy
Schroeder JW, Vezina LG. Pediatric sellar and suprasellar lesions. Pediatr Radiol. 2011 Mar;41(3):287-98; quiz 404-5. doi: 10.1007/s00247-010-1968-0. Epub
2011 Jan 26. Review. PubMed PMID: 21267556.
Empty sella

Pituitary gland measuring 2 mm or less

Can result from weakened or fenestrated diaphragma sella allowing
CSF pulsations to flatten the pituitary gland

Associated with elevated intracranial pressure, a posteriorly placed optic chiasm, and
considered a normal variant or termed “primary empty sella turcica” in the absence of
surgery, radiation therapy or medically treated intrasellar tumor

CSF occupying more than half of the sella

Found in just over 1% of patients but in almost 11% of those with
possible hypothalamic – pituitary abnormalities

Possible etiologies: congenital abnormalities as well as adverse
perinatal events
Shields R, Mangla R, Almast J, Meyers S. Magnetic resonance imaging of sellar and juxtasellar abnormalities in the paediatric population: an imaging review. Insights Imaging. 2015 Apr;6(2):241-60. doi:
10.1007/s13244-015-0401-5. Epub 2015 Mar 21. PubMed PMID: 25794595.
Schroeder JW, Vezina LG. Pediatric sellar and suprasellar lesions. Pediatr Radiol. 2011 Mar;41(3):287-98; quiz 404-5. doi: 10.1007/s00247-010-1968-0. Epub 2011 Jan 26. Review. PubMed PMID: 21267556.
Agenesis and hypoplasia of the
pituitary gland
 Rare
 Newborn with jaundice, metabolic acidosis, liver
dysfunction, adrenal and thyroid insufficiency,
severe hypoglycemia
 Associated with developmental disorders of the
midline forebrain and craniofacial structures
 Can survive with hormone replacement therapy
Spampinato MV, Castillo M. Congenital pathology of the pituitary gland and parasellar region. Top Magn Reson Imaging. 2005 Jul;16(4):269-76. Review. PubMed
PMID: 16785842.
Pituitary dwarfism

Heterogeneous group of diseases caused by isolated GH deficiency or
deficiency of multiple pituitary hormones


Imaging does not always correlate

Normal to hypoplastic to absent

Pathogenesis of MRI abnormalities is uncertain
Higher frequency in difficult deliveries (breech, perinatal asphyxia, low
Apgar)

Traumatic transection of the pituitary stalk, hypoxic injury of the hypothalamus could
result in hypoplasia of adenohypophysis, whereas regenerated hypothalamic axons
would reconstitute the neurohypophysis in a more proximal insult

Genetic causes of an abnormal interaction between the Rathke pouch and the
diencephalon have been postulated
Spampinato MV, Castillo M. Congenital pathology of the pituitary gland and parasellar region. Top Magn Reson Imaging. 2005 Jul;16(4):269-76. Review. PubMed
PMID: 16785842.
Duplicated pituitary gland
 Very rare
 Frequently accompanied by duplication of stalk
 Enlargement of the hypothalamus with fusion of the
mammillary bodies and tuber cinereum or hamartoma of the
tuber cinereum can be seen
 May result from abnormal splitting of the anterior end of the
notochord and prechordal plate due to teratogenic factors
during early embryogenesis
 May represent a variant of the median cleft face syndrome
Spampinato MV, Castillo M. Congenital pathology of the pituitary gland and parasellar region. Top Magn Reson Imaging. 2005 Jul;16(4):269-76. Review. PubMed
PMID: 16785842.
Duplicated pituitary gland
 Associated with:
 Dysgenesis of the corpus callosum
 Duplication of the anterior third ventricle
 Absence of the olfactory bulbs and tracts
 Duplication of the optic chiasm, hypothalamic hamartoma
 Hypertelorism
 Fenestration or complete duplication of the basilar artery
 Dandy-Walker spectrum
 Cleft of the basisphenoid
 Craniofacial clefting, oral midline tumors (teratomas and dermoids)
 Malformations of the spine (diplomyelia, Klippel-Feil anomaly, and clefting of
cervical posterior elements, and duplicated cervical or thoracic vertebral
bodies
Spampinato MV, Castillo M. Congenital pathology of the pituitary gland and parasellar region. Top Magn Reson Imaging. 2005 Jul;16(4):269-76. Review. PubMed
PMID: 16785842.
Duplicated pituitary gland

Duplicated pituitary glands

Duplicated pituitary stalks

Hypothalamic hamartoma
Hypothalamic hamartoma

Congenital developmental non-neoplastic grey matter heterotopia involving the
tuber cinereum, inferior hypothalamus and/or mammillary bodies which are
composed of small neuronal cells within a neutrophil-like stroma and scattered
fibrillary astrocytes

Nonenhancing hypothalamic mass contiguous with the tuber cinerum

Sessile or pedunculated

Large sessile lesions  seizures

Small pedunculated lesions  central precocious puberty

Mass located between mammillary bodies and infindibulum

On MR spectroscopy, there may be an elevated myoinositol peak
Spampinato MV, Castillo M. Congenital pathology of the pituitary gland and parasellar region. Top Magn Reson Imaging. 2005 Jul;16(4):269-76. Review. PubMed
PMID: 16785842.
Li CD, Luo SQ, Tang J, Jia G, Ma ZY, Zhang YQ. Classification of hypothalamic hamartoma and prognostic factors for surgical outcome. Acta Neurol Scand. 2014
Jul;130(1):18-26. doi: 10.1111/ane.12209. Epub 2014 Jan 2. PubMed PMID: 24382157.
Shields R, Mangla R, Almast J, Meyers S. Magnetic resonance imaging of sellar and juxtasellar abnormalities in the paediatric population: an imaging review. Insights
Imaging. 2015 Apr;6(2):241-60. doi: 10.1007/s13244-015-0401-5. Epub 2015 Mar 21. PubMed PMID: 25794595.
Hypothalamic Hamartoma
 Sessile or Pedunculated
 More common in boys
 Associated with:
Gelastic Seizures or Precocious Puberty
Hypothalamic Hamartoma
Septo-optic dysplasia
 Hypoplasia of the optic nerves, hypoplasia or absence
of the septum pellucidum, and in two thirds of cases
hypothalamic-pituitary dysfunction
 Squared appearance of the frontal horns of the lateral
ventricles and low position of the fornices on sagittal
images
 Ectopia of the posterior pituitary lobe and thin
infundibulum
Spampinato MV, Castillo M. Congenital pathology of the pituitary gland and parasellar region. Top Magn Reson Imaging. 2005
Jul;16(4):269-76. Review. PubMed PMID: 16785842.
Pediatric Neuroimaging. A. James Barkovich, Charles Raybaud. Edition 5. Lippincott Williams & Wilkins, 2012
Septo-optic dysplasia
 Hypoplasic anterior pituitary, pituitary stalk, optic chiasm, hypothalamus
 Ectopic neurohypophysis
 Absent septum pellucidum
Germ cell tumors

Divided into germinomas and nongerminomatous germ cell tumors
(70%)

Pineal region most common in males

Suprasellar region most common females

In the suprasellar cistern, most commonly centered in the stalk, with or without
involvement of the hypothalamus

Presence of basal ganglia infiltration in the setting of abnormal thickening of the
infundibulum and hypothalamus is characteristic

Variable signal characteristics; solid components enhance

T2 signal of solid components is usually iso- to hypointense compared
to gray matter
Schroeder JW, Vezina LG. Pediatric sellar and suprasellar lesions. Pediatr Radiol. 2011 Mar;41(3):287-98; quiz 404-5. doi: 10.1007/s00247-010-1968-0. Epub
2011 Jan 26. Review. PubMed PMID: 21267556.
Germ cell tumor
Suprasellar and Pineal
5-10% Synchronous suprasellar and pineal involvement
Germ cell tumor
 High risk of CSF spread: MRI of entire neuroaxis
 Isolated Diabetes Insipidus: Suspect stalk involvement
Infundibular Lesions

Classically present with diabetes inspidus

Diabetes insipidus occurs due to dysfunction of supraoptic or paraventricular nuclei of the
hypothalamus. Infiltration of these nuclei can occur at a time when the infundibulum is still
normal in size.

At the time a child presents with diabetes insipidus, a pituitary stalk lesion such as a germ cell
tumor, granuloma or lymphocytic infiltration may not be visible yet by imaging, and in such
patients repeat imaging should be obtained in 3 to 6 months and, if still negative, a second
repeat examination should be obtained.


Three most common etiologies:

Langerhans histiocytosis (LCH)

Germ cell tumor (GCT)

Lymphocytic hypophysitis
Isolated thickening:

Sarcoidosis

Granulomatous infections, such as TB
Pediatric Neuroimaging. A. James Barkovich, Charles Raybaud. Edition 5. Lippincott Williams & Wilkins, 2012
Schroeder JW, Vezina LG. Pediatric sellar and suprasellar lesions. Pediatr Radiol. 2011 Mar;41(3):287-98; quiz 404-5. doi: 10.1007/s00247-010-1968-0. Epub 2011 Jan 26. Review. PubMed PMID: 21267556.
Infundibular mass differential

Germinoma

Lymphocytic hypophysitis

Langerhans cell histiocytosis

Adenoma or nonadenomatous pituitary tumors

Granulomatous disease (sarcoid, wegner granulomatosis, tuberculosis)

Lymphoma

Metastatic disease

Other infiltration disease: Erdheim-Chester, Rosai Dorfman
Langerhans cell histiocytosis

LCH involves CNS in 4% of cases

In nearly all cases of LCH, the normal T1 hyperintensity of the neurohypophysis is absent

Hypothalamus and infundibulum are infiltrated in up to 20% (most common location in CNS)

When only neurohypophysis and infundibulum involved there is classically thickening of the
pituitary stalk greater than 3.5 mm with loss of the pituitary bright spot

When entire gland is involved, diffuse inflammatory changes may be present which may
involve optic chiasm or cavernous sinuses

Multiple CNS findings have been described:

White and gray matter lesions

Demyelination

Calvarial lesions

Partially empty sella

Extraparenchymal masses

Cerebellar degeneration
Schroeder JW, Vezina LG. Pediatric sellar and suprasellar lesions. Pediatr Radiol. 2011 Mar;41(3):287-98; quiz 404-5. doi: 10.1007/s00247-010-1968-0. Epub
2011 Jan 26. Review. PubMed PMID: 21267556.
Thickening of the pituitary stalk
in LCH
Lymphocytic hypophysitis
 Classified by anatomical location
 Adenophyophysis
 Infundibulum
 Neurohypophysis
 When infundibulum and neurohypophysis are involved
diabetes insipidus is the most common symptom
 In children – 50% of cases involve anterior and
posterior pituitary lobes
Schroeder JW, Vezina LG. Pediatric sellar and suprasellar lesions. Pediatr Radiol. 2011 Mar;41(3):287-98; quiz 404-5. doi: 10.1007/s00247-010-1968-0. Epub
2011 Jan 26. Review. PubMed PMID: 21267556.
Sarcoidosis
 Prevalence in children is unknown
 Prepubertal children with neurosarcoid may
demonstrate seizure and hypothalamic
dysfunction
Schroeder JW, Vezina LG. Pediatric sellar and suprasellar lesions. Pediatr Radiol. 2011 Mar;41(3):287-98; quiz 404-5. doi: 10.1007/s00247-010-1968-0. Epub
2011 Jan 26. Review. PubMed PMID: 21267556.
Thickening of the pituitary stalk
in sarcoidosis
Conclusions

The normal neonatal, pubertal and young adult pituitary gland have their own
distinct appearances that should not be confused with congenital pathology

Knowledge of normal embryology of the pituitary gland, particularly the
development of adenohypophysis from the Rathke pouch and of the
neurohypophysis from the diencephalon, is central to the understanding of
congenital pathology

When a child presents with diabetes insipidus, a pituitary stalk lesion may not be
visible yet by imaging, and in such patients repeat imaging should be obtained in
3 to 6 months and, if still negative, a second repeat examination should be
obtained

Interpretation of imaging features of acquired disorders also is enhanced by
grasping basic concepts of hypothalamic-pituitary axis embryology and function