Case Report
Brahim El Mostarchid, Najia El Abbadi, Fouad Bellakhdar
Methods: We report the case of a 34-year-old Moroccan woman who developed progressive history of decreasing vision in both eyes. The skull films showed diffuse pneumatisation of the ethmoid and sphenoid sinuses. The CT scan showed a mass occupying the planum sphenoidale and evident pneumosinus dilatans with so-called “blistering”. CT scan on bone views showed diffuse pneumatisation of the fronto-ethmoidal and sphenoid sinuses. MR imaging confirmed the diagnosis. The patient underwent a right frontal craniotomy. There was a meningioma of planum sphenoidale that was totally excised.
Results: This case provides further evidence that pneumosinus dilatans is a sign of intracranial meningioma.
Keywords: Pneumosinus dilatans, CT scan, MR imaging and planum sphenoidale meningioma
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INTRODUCTION
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Pneumosinus dilatans consists of an abnormal dilatation of the paranasal
air sinuses, which contain only air and are lined by normal epithelium.
Pneumosinus dilatans affecting the sphenoid and posterior ethmoid sinuses
has been reported in association with spheno-orbital meningiomas and is
believed by some authors to be a sign of an adjacent meningioma.(1-6)
A case of pneumosinus dilatans associated with planum sphenoidale meningioma
is reported.
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CASE
REPORTS
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A 34-year-old Moroccan woman was admitted to our Neurosurgery Department
with a six-month history of decreasing vision in both eyes. She was in
excellent general health and neurological examination was normal. On neuro-ophthalmology
evaluation, her visual acuity was 2/10 in the right eye and 8/10 in the
left eye. The rest of examination was normal. The fundus showed optic
atrophy in left eye and papilloedema in right eye. Visual fields showed
constriction. The skull films showed diffuse pneumatisation of the ethmoid
and sphenoid sinuses. The CT scan showed a mass occupying space of the
planum sphenoidale and evident pneumosinus dilatans with so-called “blistering”
(Fig. 1 and 2). CT scan with bone windows showed diffuse pneumatisation
of fronto-ethmoidal, sphenoid and maxillary sinuses (Fig. 3). MR imaging
confirmed the diagnosis. The mass was hypointense in T1-weighted image
and hyperintense on T2-weighted image. The mass homogenously enhanced
with gadolinium (Fig. 4). The patient underwent a right frontal craniotomy.
The meningioma arising from planum sphenoidale was totally excised. Histological
examination confirmed the operative finding. Post-operatively, the patient’s
visual fields and acuity were not changed over a 10 months follow-up period.
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| Figure 1 - CT scan sagittal view with infusion of contrast showing abnormal dilatation of sphenoidale and ethmoidal sinuses extending to a planum sphenoidale meningioma. Pneumosinus dilatans associated with planum sphenoidale meningioma | Figure 2 - CT scan sagittal view with bone window showing abnormal dilatation of sphenoidale and ethmoidal sinus. |
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| Figure 2 — Case 1: CT scan shows the foreign body in the superior orbital fissure and extending to the medial aspect of the temporal lobe lateral to the pons. | Figure 3 — Case 1: Carotid angiogram revealed the proximity of the pencil to the parasellar region with normal filling of the vasculature. |
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DISCUSSION
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Pneumosinus dilatans is a rare condition characterised by enlargement
of the paranasal sinuses without evidence of localised bone or mucus-membrane
changes.(1,2)
Pneumosinus dilatans affecting the sphenoid and posterior ethmoid sinuses
has been reported in association with spheno-orbital meningiomas and is
believed by some authors to be an early sign of an adjacent meningioma.
The condition is most commonly observed when it affects the sphenoid sinus
as a response to a local meningioma of the tuberculum sellae or planum
sphenoidale.(3,4) Pneumosinus dilatans is often associated with hyperostosis
and blistering. Blistering phenomena is abnormal convexity of the planum
sphenoidale. Pneumosinus dilatans is known to be an early sign of meningioma
of the anterior chiasmatic angle.
Pneumosinus dilatans is a rare condition that is capable of causing progressive
optic atrophy and bitemporal field defects. Although it may involve the
maxillary, ethmoid or sphenoid sinuses, the extent to which it represents
a true pathological entity, rather than an anatomical variant of normal
sinus architecture. Many previous cases of progressive optic neuropathy
associated with pneumosinus dilatans affecting the sphenoid and posterior
ethmoid sinuses have been found to be caused by adjacent optic nerve sheath
meningiomas.
Meningiomas that arise at the intracranial end of the optic canal may
originate from the dural covering of the optic nerve and are therefore
contiguous with the optic nerve sheath. The visual dysfunction and abnormality
of field loss in these patients result in direct compression or ischaemia
of the optic nerves. The mechanism of the optic nerve involvement and
progressive optic atrophy in case of meningioma of planum sphenoidale
without contact with optic nerve is unclear. Due to the normal optic nerve
vasculature and absence of direct compression by meningioma, the optic
nerve involvement in this case is probably caused by increased pressure
within the sphenoid sinus transmitted to the optic nerve through defect
in the pneumatised optic canal.(1)
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CONCLUSION
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The importance of recognising this condition is to alert the radiologist
for possible presence of an occult meningioma requiring soft-tissue imaging
techniques (computed tomography or magnetic resonance imaging). The presence
of fibroosseous disease can usually be recognised by plain radiography.
This case provides further evidence that pneumosinus dilatans is a sign
of intracranial meningioma.(2-6 )
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REFERENCES
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| 1. | Hirst LW, Miller NR, Allen GS: Sphenoidal pneumosinus dilatans with bilateral optic nerve meningiomas. Case report. J Neurosurg 1979, 51(3): 402-407 |
| 2. | Hirst LW, Miller NR, Hodges FJ, Corbett JJ, Thompson: Sphenoid pneumosinus dilatans. A sign of meningioma originating in the optic canal. Neuro-Radiol 1982, 22(4): 207-210 |
| 3. | Leonardi M, Fabris G: A direct radiological sign of meningioma of the anterior angle of the chiasma: “Pneumosinus dilatans.” Ann Radiol (Paris) 1976, 19(8): 803-806 |
| 4. | 803-806 4. Lloyd GA: Orbital pneumosinus dilatans. Clin Radiol 1985, 36(4): 381-386 |
| 5. | Miller NR, Golnik KC, Zeidman SM, North RB: Pneumosinus dilatans: A sign of intracranial meningioma. Surg Neurol 1996, 46(5): 471-474 |
| 6. | Seutin B, Cornelis G, Vandresse JH. Early signs of meningiomas of the anterior chiasmatic angle: “Pneumosinus dilatans and hyperostosis” and “blistering”. J Belge Radiol 1979, 62(6): 587-595 |
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