statdx/docs_md/articles/absent-thin-infundibular-stalk_28acc91f-2d29-40b9-8a91-b02f16fe1284.md

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title: "Absent/Thin Infundibular Stalk" docid: "28acc91f-2d29-40b9-8a91-b02f16fe1284" authors:

• key: "d19354f3-7ff2-495a-ad3f-064122e45602" value: "Bernadette L. Koch, MD"
• key: "f184750a-90b4-47a7-907b-23b05d70357a" value: "Chang Yueh Ho, MD"
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• "Brain"
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ESSENTIAL INFORMATION

• Key Differential Diagnosis Issues

  • Congenital or acquired
  • History of trauma or sellar/suprasellar surgery

• Helpful Clues for Common Diagnoses

  • Pituitary Stalk Transection, Posttraumatic - Usually occurs following motor vehicle accident - Can occur with closed head injury - ± accompanying basilar skull fracture
  • **Pituitary Stalk Transection,**Postsurgical - Children: Commonly after craniopharyngioma resection - Adults: Commonly after macroadenoma resection

• Helpful Clues for Less Common Diagnoses

  • Septo-Optic Dysplasia - Optic nerve hypoplasia, often asymmetric - ± absent septum pellucidum, sometimes partial - ± ectopic posterior pituitary - Pituitary dysfunction in most patients, even if normal-appearing pituitary - ± polymicrogyria &/or schizencephaly
  • Holoprosencephaly - Failure of prosencephalon cleavage - 70% with diabetes insipidus from hypothalamic fusion
  • Pituitary Stalk Anomalies - Ectopic posterior pituitary - Posterior pituitary T1 "bright spot" in hypothalamus - Rarely partial ectopia: 1 bright spot in normal location & 1 ectopic - Stalk thin or absent, shallow sella, small pituitary - Associated with septo-optic dysplasia - Duplicated stalk - 2 separate, thinned stalks seen on coronal view - Associated with 2 pituitary glands and basilar arteries - Tuber cinereum thickened, often fused with mammary bodies - Craniofacial anomalies - Theorized from splitting of rostral notochord during blastogenesis - Persistent embryonic infundibular recess - Proposed from failure of closure of embryonal infundibular recess - Tubular cyst of stalk connecting 3rd ventricle and sella - Best seen on sagittal views
  • Pituitary Stalk Interruption Syndrome - Pickardt-Fahlbusch syndrome - Most likely multigenic origin and inheritance pattern - Whole exome sequencing potential genes related to the Wnt, Notch, & sonic hedgehog signaling pathways that regulate pituitary embryogenesis - Thin, interrupted, attenuated or absent pituitary stalk - Aplasia or hypoplasia of anterior pituitary - Absent or ectopic posterior pituitary - Hormonal deficiencies except for hyperprolactinemia - Most patients referred later in childhood for growth retardation - Viewed as mild form of holoprosencephaly spectrum

• Helpful Clues for Rare Diagnoses

  • Meningitis - Children with group B streptococcus - Diencephalic infarction - Secondary atrophy of optic chiasm, pituitary stalk
  • Neurocysticercosis - Racemose neurocysticercosis cysts stretch infundibular stalk

References

Selected References

1. Huang J et al: Noncontrast MRI protocol for selected pediatric pituitary endocrinopathies: a procedure with high diagnostic yield and potential to reduce anesthesia and gadolinium-based contrast exposure. AJNR Am J Neuroradiol. 42(10):1884-90, 2021
2. Voutetakis A: Pituitary stalk interruption syndrome. Handb Clin Neurol. 181:9-27, 2021
3. Brauner R et al: Pituitary stalk interruption syndrome is characterized by genetic heterogeneity. PLoS One. 15(12):e0242358, 2020
4. Ybarra M et al: A new imaging entity consistent with partial ectopic posterior pituitary gland: report of six cases. Pediatr Radiol. 50(1):107-15, 2020
5. Sen D et al: Duplication of the pituitary gland - plus syndrome. Indian J Radiol Imaging. 26(1):126-30, 2016
6. Voutetakis A et al: Pituitary stalk interruption syndrome: cause, clinical manifestations, diagnosis, and management. Curr Opin Pediatr. 28(4):545-50, 2016
7. Glastonbury CM et al: Masses and malformations of the third ventricle: normal anatomic relationships and differential diagnoses. Radiographics. 31(7):1889-905, 2011
8. Reynaud R et al: Pituitary stalk interruption syndrome in 83 patients: novel HESX1 mutation and severe hormonal prognosis in malformative forms. Eur J Endocrinol. 164(4):457-65, 2011
9. Steno A et al: Persisting embryonal infundibular recess. J Neurosurg 110: 359-62, 2009

Images

Selected Images

Pituitary Stalk Transection, Posttraumatic Sagittal T1 C+ MR shows surgical absence of the pituitary stalk and hypothalamus from a transsphenoidal approach. Postsurgical changes are seen in the sphenoid sinus and nasal cavity .

Pituitary Stalk Transection, Posttraumatic Sagittal T1 C+ MR shows surgical absence of the pituitary stalk and hypothalamus from a transsphenoidal approach. Postsurgical changes are seen in the sphenoid sinus and nasal cavity .

Septo-Optic Dysplasia Coronal T2 MR shows absence of the septum pellucidum and thinning of the pituitary infundibulum . Other midline defects of septo-optic dysplasia not shown here include optic nerve hypoplasia and ectopic posterior pituitary.

Septo-Optic Dysplasia Coronal T1 MR shows absence of the septum pellucidum and nodular T1 hyperintensity in the hypothalamus , consistent with ectopic posterior pituitary. The infundibulum is not visualized.

Holoprosencephaly Sagittal T1 MR shows ectopic posterior pituitary , absent infundibulum, and shallow sella with hypoplastic pituitary gland . Additionally, there is dysplasia of the callosal genu with thickening around the anterior commissure from fusion of the caudate nuclei in this case of semilobar holoprosencephaly.

Pituitary Stalk Anomalies Sagittal T1 MR in a child with short stature and growth hormone deficiency shows a lack of normal posterior pituitary bright spot in the dorsal aspect of the sella. Instead, there is an ectopic posterior pituitary bright spot and absent pituitary stalk .

Pituitary Stalk Interruption Syndrome T1 C+ MR shows a T1-hyperintense mass of the hypothalamus , which was hyperintense prior to contrast. There is a lack of normal enhancing infundibulum. Ectopic posterior pituitary and absent stalk is a potential radiographic finding for stalk interruption syndrome.

Pituitary Stalk Anomalies Coronal T1 C+ FS MR in an 8-year-old child with multiple congenital anomalies demonstrates duplicated infundibular stalks and adenohypophyses and thickening of the hypothalamus .

Pituitary Stalk Anomalies Axial T2 MR shows a persistent infundibular recess . There is additional cleft lip and hydrocephalus with medial atrial diverticulum .

Additional Images

Pituitary Stalk Anomalies Sagittal T1 MR shows enlarged CSF space communicating from a displaced 3rd ventricle into a persistent infundibular recess . Note fat within a persistent craniopharyngeal canal , cleft palate , and downward herniation of the cerebellum due to hydrocephalus from aqueductal stenosis.

Pituitary Stalk Anomalies .Coronal T1 MR shows thinned, duplicated infundibular stalks and thickening of the tuber cinereum .

Pituitary Stalk Transection, Posttraumatic Sagittal T1 MR in a patient with hypopituitarism following transsphenoidal hypophysectomy shows an empty sella and a very thin, attenuated infundibular stalk .

Pituitary Stalk Transection, Postsurgical Sagittal T1 C+ FS MR following transsphenoidal hypophysectomy shows that the thinned stalk is stretched and retracted inferiorly into the partially empty sella .

Pituitary Stalk Transection, Posttraumatic Coronal T1 MR in a child with remote head trauma who subsequently developed pituitary insufficiency shows traumatic cephalocele and absent/inapparent pituitary stalk .

Pituitary Stalk Transection, Postsurgical Sagittal T1WI MR after transsphenoidal hypophysectomy shows a very thin infundibular stalk along with secondary empty sella .

Pituitary Stalk Anomalies Sagittal T1 MR in a 2-year-old child with short stature and abnormally low bone age shows an absent infundibular stalk , ectopic posterior pituitary bright spot , and small pituitary gland .

Pituitary Stalk Anomalies Coronal T1 MR shows absent stalk and ectopic posterior pituitary bright spot in the hypothalamus .

Pituitary Stalk Anomalies Sagittal T1 MR shows 2 small-sized pituitary stalks in this case of duplicated pituitary stalks. Note abnormal configuration of posterior pituitary .

Septo-Optic Dysplasia Coronal T2 MR shows classic SOD with thin stalk , inferiorly "pointed" frontal horns , and absent septum pellucidum with squared-off appearance of lateral ventricles .

Neurocysticercosis Sagittal T1 C+ MR shows racemose neurocysticercosis cysts surrounding and stretching the infundibular stalk , extending into the sella and flattening the pituitary gland against the floor .