DOI:10.2214/AJR.07.2849
AJR 2008; 190:W77
© American Roentgen Ray Society
Pituitary Duplication or Suprasellar Encephalocele?
Fabrice Bonneville
Hôpital Pitié-Salpêtrière, Paris,
France
WEB—This is a Web exclusive article.
Note—I am grateful to Jean-François Bonneville for his
critical review of the manuscript.
We read with interest the article by Hamilton et al.
[1] nicely reporting on the
spectrum of pituitary infundibulum lesions. We wanted, however, to make a
short comment. We think that the reported abnormality incidentally observed in
a 69-year-old man in Figure 6 of the article illustrates a case of a
suprasellar encephalocele (or ventriculocele) rather than a hypophyseal
duplication, as suggested by the authors.
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Fig. 1A —33-year-old woman with partial anterior pituitary lobe insufficiency
and intrasellar encephalocele. Sagittal T2-weighted (A) gland sagittal
T1-weighted gadolinium-enhanced (B) images reveal cystic
intrasellar-suprasellar lesion in continuation with third ventricle. Floor of
third ventricle is displaced downward in sella, whereas enhancing stalk and
pituitary gland are laminated anteriorly.
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View larger version (167K):
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Fig. 1B —33-year-old woman with partial anterior pituitary lobe insufficiency
and intrasellar encephalocele. Sagittal T2-weighted (A) gland sagittal
T1-weighted gadolinium-enhanced (B) images reveal cystic
intrasellar-suprasellar lesion in continuation with third ventricle. Floor of
third ventricle is displaced downward in sella, whereas enhancing stalk and
pituitary gland are laminated anteriorly.
|
|
Hypophyseal duplication is usually diagnosed in childhood in association
with partial twinning or median cleft facial syndrome
[2]. Its exact origin is not
completely elucidated, but it might result from the splitting of both the
developing adenohypophysis and the neurohypophysis related to a median
clefting, with subsequent development of two separate pituitary glands and
stalks visible only on a coronal plane
[3]. The hypothalamus is
reported to be either normal or thick but not discontinuous
[3]. However, in Figure 6 of
the Hamilton et al. [1]
article, the anterior pituitary gland looks normal and a defect is observed in
the sagittal plane at the anterior aspect of the floor of the third ventricle,
enlarging the infundibular recess. Such small encephaloceles are usually
asymptomatic. If larger, with an intrasellar or even a transsellar component,
they can lead to nasopharynx mass; cerebrospinal fluid rhinorrhea; or, rarely,
hypophyseal deficiency [4,
5]. For reinforcement, we
illustrate the case of a 33-year-old woman with partial anterior pituitary
lobe dysfunction caused by a large intrasellar encephalocele mimicking a
cystic adenoma (Fig. 1A,
1B).
We think that a clear distinction between hypophyseal duplication and
intrasellar encephalocele should be determined because the latter may
erroneously mimic cystic adenoma, as seen in the previous case, whereas the
former most commonly occurs in association with complicated midline and skull
base anomalies in childhood.
References
- Hamilton BE, Salzman KL, Osborn AG. Anatomic and pathologic
spectrum of pituitary infundibulum lesions. AJR2007; 188: 715;
[web]W223-232
- Shroff M, Blaser S, Jay V, Chitayat D, Armstrong D. Basilar artery
duplication associated with pituitary duplication: a new finding.
Am J Neuroradiol 2003;24
: 956-961[Abstract/Free Full Text]
- Ryals BD, Brown DC, Levin SW. Duplication of the pituitary gland as
shown by MR. Am J Neuroradiol 1993;14
: 137-139[Abstract]
- Herman P, Sauvaget E, Guichard JP, Tran Ba Huy P. Intrasphenoidal
transsellar encephalocele repaired by endoscopic approach. Ann Otol
Rhinol Laryngol 2003; 112:890
-893[Medline]
- Ellyin F, Khatir AH, Singh SP. Hypothalamic-pituitary functions in
patients with transsphenoidal encephalocele and midfacial anomalies.
J Clin Endocrinol Metab 1980;51
: 854-856[Abstract/Free Full Text]
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