Persistent hypophyseal canal

Magnetic
resonance imaging of sellar and juxtasellar abnormalities in the paediatric population: an imaging review. Persistent craniopharyngeal canal. Axial (a) and sagittal (b) CT shows a markedly enlarged persistent craniopharyngeal canal. Coronal fat-suppressed T1WI shows inferior extension of enhancing pituitary tissue within the abnormally enlarged craniopharyngeal canal (c)
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A rare case
of persistent hypophyseal canal with ectopic pituitary teratoma. Conventional radiograph shows vertically elongated sella and obliteration of nasopharyngeal air-column.
www.eurorad.org • CC by-nc-sa-4.0
A rare case
of persistent hypophyseal canal with ectopic pituitary teratoma. Sagittal CT image shows a well-corticated persistent craniopharyngeal canal associated with a mass in nasopharynx.
www.eurorad.org • CC by-nc-sa-4.0
A rare case
of persistent hypophyseal canal with ectopic pituitary teratoma. Coronal contrast-enhanced CT image shows mass in nasopharynx containing enhancing soft tissue, osseous and lipomatous components.
www.eurorad.org • CC by-nc-sa-4.0
A rare case
of persistent hypophyseal canal with ectopic pituitary teratoma. Sagittal contrast-enhanced CT image shows pituitary stalk extending into the persistent craniopharyngeal canal.
www.eurorad.org • CC by-nc-sa-4.0
A rare case
of persistent hypophyseal canal with ectopic pituitary teratoma. Sagittal T1-weighted image shows hyperintense lipomatous component within the mass in nasopharynx.
www.eurorad.org • CC by-nc-sa-4.0
A rare case
of persistent hypophyseal canal with ectopic pituitary teratoma. Axial T2-weighted image shows hyperintense lipomatous and hypointense calcific components within the mass in nasopharynx.
www.eurorad.org • CC by-nc-sa-4.0
A rare case
of persistent hypophyseal canal with ectopic pituitary teratoma. Sagittal T2-weighted 3D DRIVE CLEAR image shows mass in nasopharynx and cerebrospinal fluid filled craniopharyngeal canal with infundibulum extending from the hypothalamus and into the persistent canal.
www.eurorad.org • CC by-nc-sa-4.0
Radiopaedia • CC-by-nc-sa 3.0 • de

Persistent hypophyseal canal, also known as the craniopharyngeal canal when larger than 1.5 mm in diameter, is a rare congenital defect characterized by a communication through the central skull base between the nasopharynx and the pituitary fossa.

Terminology

There are a number of terms which refer to this abnormality and some authors distinguish between canals based on whether they are larger or smaller than 1.5 mm in diameter. To avoid confusion:

  • a canal less than 1.5 mm in diameter
    • persistent hypophyseal canal
  • a canal greater than 1.5 mm in diameter
    • craniopharyngeal canal
    • large craniopharyngeal canal
    • transphenoidal canal

The remainder of this article will refer to the defect as a persistent hypophyseal canal, keeping in mind that when large, alternative terms are preferable.

Additionally, the larger defects are possibly more closely related to transsphenoidal meningoencephaloceles than to persistent hypophyseal canals .

Epidemiology

The prevalence of persistent hypophyseal canals has been reported to be as high as 0.42% .

Clinical presentation

In most cases, individuals with a persistent canal are asymptomatic. Possible presentations include :

In addition, many craniofacial anomalies have been reported, especially with the larger defects, including :

Pathology

The exact cause of these defects is uncertain, as is whether or not they all share the same underlying etiology. Two theories have been proposed:

  • persistence of Rathke's pouch
  • persistence of a vascular channel

    • Radiographic features

    Persistent hypophyseal canals, as well as the larger craniopharyngeal canals, are found in the midline, oriented vertically and extending form the floor of the pituitary fossa to the posterior wall of the nasopharynx, passing behind the sphenoid sinus.

    CT

    They are best appreciated on thin slice bone filter CT, and appear as a sharply circumscribed corticated canal.

    Differential diagnosis

    Siehe auch:
    Assoziationen und Differentialdiagnosen zu persistierender Canalis craniopharyngealis:
    Canalis
    basilaris medianus
    Wikipedia • CC BY-SA 4.0
    kongenitale
    Anomalien der Sellaregion
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